项目文件结构

项目运行效果

项目详细代码

JDBCUtils.java

package jdbc;import java.sql.*;
import com.mysql.jdbc.Driver;public class JDBCUtils {private static final String connectionURL="jdbc:mysql://localhost:3306/books?useSSL=false&useUnicode=true&characterEncoding=UTF8";private static final String username="root";private static final String password="1234";public  static Connection getConnection(){try {Class.forName("com.mysql.jdbc.Driver");return DriverManager.getConnection(connectionURL,username, password);} catch (Exception e) {e.printStackTrace();}return null;}public  static void  close(ResultSet rs,Statement stmt,Connection conn){try {if(rs!=null)rs.close();} catch (SQLException e) {e.printStackTrace();}try {if(stmt!=null)stmt.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(conn!=null)conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}
}

Register.java

package jdbc;import java.util.Scanner;public class Register {String[] Username = new String[20]; String[] Password = new String[20]; public  void loginfirst(){Scanner input=new Scanner(System.in);int num=0;boolean sign = false;do{ System.out.println("   温馨提示：请先注册！！！ ");System.out.println("            1.注册帐号                                 "); System.out.println("            2.登录系统                                 "); System.out.println("            3.退出系统                                 ");String a = input.next(); switch(a){ case "1": do{	System.out.println("请输入想要注册的用户名"); Username[num] = input.next(); System.out.println("请输入想要注册的密码"); String passwordfirst = input.next(); System.out.println("请再次输入密码"); String passwordsecond = input.next(); if(passwordfirst.equals(passwordsecond)){ Password[num] = passwordfirst; System.out.println("新用户："+Username[num]+"创建成功"); sign = true;                      }else{ System.out.println("两次输入的密码不一致"); sign = false; } }while(!sign); num++; continue;case "2": sign = false; break; case "3": System.exit(-1); } }while(sign);}		  public void loginsecond(){boolean  flag=true;Scanner in=new Scanner(System.in); do{ System.out.println("请输入登陆账号"); String username = in.next(); System.out.println("请输入密码"); String password = in.next();for(int i=0;i<Username.length;i++){ if(username.equals(Username[i])&&password.equals(Password[i])){ System.out.println("登陆中"); try {Thread.sleep(1500);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("登陆成功");flag= false; break; }   } if(flag==true){ System.out.println("账号或者密码错误，请重新登录"); flag = true; }   }while(flag); }	}

Test.java

package jdbc;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;public class Test {public static void main(String[] args) {}public static void selectAll()
{Connection con=null;Statement stmt=null;ResultSet rs=null;try {con=JDBCUtils.getConnection();stmt=con.createStatement();rs=stmt.executeQuery("select * from book,bookmagic where book.bno=bookmagic.bno");System.out.println(" 编号                   书籍名               主人              页码                价格                 作者  ");while(rs.next()){int bno=rs.getInt("bno");String name=rs.getString("name");String owner=rs.getString("owner");int page=rs.getInt("page");int price=rs.getInt("price");String article=rs.getString("article");System.out.println(" "+bno+"         "+name+"               "+owner+"              "+page+"          "+price+"           "+ article);System.out.println("                               ");}  } catch (Exception e) {e.printStackTrace();} finally{JDBCUtils.close(rs, stmt, con);}
}public static void  selectUserByPage(int  pageNumber,int pageCount){Connection con=null;	PreparedStatement stmt=null;ResultSet rs=null;try {con=JDBCUtils.getConnection();stmt=con.prepareStatement("select* from book limit ?,?");//mysql中 使用limit查询的参数第一个为  起始记录数; 第二个为 每页的数量stmt.setInt(1, (pageNumber-1)*pageCount);stmt.setInt(2, pageCount);rs=stmt.executeQuery();while(rs.next()){int bno=rs.getInt("bno");String name=rs.getString("name");String owner=rs.getString("owner");int page=rs.getInt("page");int price=rs.getInt("price");System.out.println("-----------------------------");System.out.println(" 编号   书籍名  主人  页码   价格   ");System.out.println("  "+bno+"    "+name+"  "+owner+"    "+page+"   "+price);System.out.println("-----------------------------");}  } catch (Exception e) {e.printStackTrace();} finally{ JDBCUtils.close(rs, stmt, con);}}public static void insert(int number,String passname,String own,int pages,int prices)
{Connection con=null;PreparedStatement stmt=null;ResultSet rs=null;try {con=JDBCUtils.getConnection();String sql="insert into book  values(?,?,?,?,?)";stmt=con.prepareStatement(sql);stmt.setInt(1, number);;stmt.setString(2, passname);stmt.setString(3, own);stmt.setInt(4, pages);stmt.setInt(5, prices);int result =stmt.executeUpdate();//返回值代表收到影响的行列} catch (Exception e) {e.printStackTrace();} finally{System.out.println("添加成功！！");JDBCUtils.close(rs, stmt, con);}	
}public  static  void delete (int price)
{Connection con=null;PreparedStatement stmt=null;ResultSet rs=null;try {con=JDBCUtils.getConnection();String sql="delete from book where price= ?";stmt=con.prepareStatement(sql);stmt.setInt(1, price);;int result =stmt.executeUpdate();//返回值代表收到影响的行列if(result>0){System.out.println("删除成功！"); }else{System.out.println("删除失败！");}} catch (Exception e) {e.printStackTrace();} finally{	JDBCUtils.close(rs, stmt, con);}		
}public static  void update(int number,String passname,String own,int pages,int prices){Connection con=null;PreparedStatement stmt=null;ResultSet rs=null;try {con=JDBCUtils.getConnection();String sql="update book set price=?,name=?,owner=?,page=? where bno=? ";stmt=con.prepareStatement(sql);stmt.setInt(1, prices);stmt.setString(2, passname);stmt.setString(3, own);stmt.setInt(4, pages);stmt.setInt(5, number);int result =stmt.executeUpdate();//返回值代表收到影响的行列if(result>0){System.out.println("更新成功！"); }else{System.out.println("更新失败！");}} catch (Exception e) {e.printStackTrace();} finally{	JDBCUtils.close(rs, stmt, con);}		
}
}

CURD.java

package jdbc;import java.util.Scanner;public class CURD {public static void main(String[] args) {Register t=new Register();t.loginfirst();t.loginsecond();Test te=new Test();Scanner input = new Scanner(System.in);while(true){menu();int a = input.nextInt();switch(a) {case 1:     te.selectAll();break;case 2:     System.out.println("请输入起始记录数：");int pageNumber = input.nextInt();System.out.println("每页的数量");int  pageCount= input.nextInt();te.selectUserByPage(pageNumber,pageCount); break; case  3: System.out.println("请输入添加的书籍编号：");int number = input.nextInt();System.out.println("请输入添加的书籍名字：");String passname = input.next();System.out.println("请输入添加的书籍主人：");String own = input.next();System.out.println("请输入添加的书籍页码：");int pages = input.nextInt();System.out.println("请输入添加的书籍价格：");int prices = input.nextInt();te.insert(number,passname,own,pages,prices);  break;case 4:  System.out.println("请输入你要删除的书籍的对应的价格：");int prices1=input.nextInt();te.delete(prices1);break;case 5:System.out.println("请根据需求进行书籍信息的修改：");System.out.println("                             ");System.out.println("你要更新书籍编号：");int number2 = input.nextInt();System.out.println("你要更新书籍名字：");String passname2 = input.next();System.out.println("你要更新书籍主人：");String own2 = input.next();System.out.println("你要更新书籍页码：");int pages2 = input.nextInt();System.out.println("你要更新书籍的价格：");int prices3 = input.nextInt();te.update(number2,passname2,own2,pages2,prices3);break;case 6 :System.out.println("操作结束");System.exit(-1);}}}public  static void menu()  {System.out.println(" ---------- ∮ 书籍管理系统 ∮   -------------");System.out.println("                                          ");System.out.println("          》 1.  查询所有书籍信息                   ");System.out.println("          》 2.  分页查询书籍信息                     ");System.out.println("          》 3.  增加书籍信息                   ");System.out.println("          》 4.  删除书籍信息                     ");System.out.println("          》 5.  修改书籍信息                     ");System.out.println("-----------------------------------------");System.out.println("          》 6.  操作结束                                     ");System.out.println("         ∮ 请输入你要输入的编号 :           ");}} 

项目文件下载

点击下载源码

相关案例

案例一

package hello;
import java.sql.*;
import java.awt.AWTException;
import java.awt.Robot;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.util.Scanner;
public class 实验 {static void clear() throws AWTException  //清屏{        Robot r = new Robot();        r.mousePress(InputEvent.BUTTON3_MASK);       // 按下鼠标右键        r.mouseRelease(InputEvent.BUTTON3_MASK);    // 释放鼠标右键        r.keyPress(KeyEvent.VK_CONTROL);             // 按下Ctrl键        r.keyPress(KeyEvent.VK_R);                    // 按下R键        r.keyRelease(KeyEvent.VK_R);                  // 释放R键        r.keyRelease(KeyEvent.VK_CONTROL);            // 释放Ctrl键        r.delay(100);            }static void jumplong() throws InterruptedException	//跳转暂停{System.out.println("五秒后自动跳转");Thread.sleep(5000);}static void jumpshort() throws InterruptedException	//跳转暂停{System.out.println("两秒后自动跳转");Thread.sleep(2000);}public static void add() throws Exception                                           //增加学生信息{Connection con = null;PreparedStatement ps=null;try {Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");Scanner a=new Scanner(System.in);while(true){System.out.print("输入学生姓名：");String name=a.next();System.out.print("输入学生性别：");String sex=a.next();System.out.print("输入学生地址：");String site=a.next();System.out.print("输入学生专业：");String major=a.next();System.out.print("输入学生专业成绩：");Float maiorgrade=a.nextFloat();String sql="insert into student(name,sex,site,major,majorgrade)values(?,?,?,?,?)";ps = con.prepareStatement(sql);ps.setString(1,name);ps.setString(2,sex);ps.setString(3,site);ps.setString(4,major);ps.setFloat(5,maiorgrade);ps.execute();System.out.println("是否继续输入学生信息\t请输入yes/no");String no="no";String choose=a.next();clear();if(no.equals(choose))break;}} catch (Exception e) {// TODO 自动生成的 catch 块e.printStackTrace();}finally {ps.close();con.close();}}public static void alldata() throws Exception{Connection con = null;Statement sta = null;ResultSet rs = null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");sta = con.createStatement();String sql="select * from student";rs=sta.executeQuery(sql);//执行sql语句System.out.println("学生姓名\t学生性别\t学生地址\t学生专业\t学生专业成绩");while(rs.next()){System.out.println(rs.getString(1)+"\t"+rs.getString(2)+"\t"+rs.getString(3)+"\t"+rs.getString(4)+"\t"+rs.getString(5));}}public static void delete() throws Exception				   //删除{Connection con = null;Statement sta = null;ResultSet rs = null;PreparedStatement ps=null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");boolean n=true;int y=0;while(n){System.out.print("请输入要删除的学生姓名：");Scanner a=new Scanner(System.in);String name=a.next();sta = con.createStatement();String sql="select * from student",Sql;rs=sta.executeQuery(sql);//执行sql语句while(rs.next()){int m=name.compareTo(rs.getString(1));if(m==0){y=1;}}if(y==0){System.out.println("该用户名不存在，请重新输入");continue;}Sql="delete from student where name = ? ";ps = con.prepareStatement(Sql);ps.setObject(1, name);ps.execute();n=false;System.out.println("删除成功！");}}public static void updata() throws Exception				   //更新{Connection con = null;Statement sta = null;ResultSet rs = null;PreparedStatement ps=null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");boolean n=true;int y=0;while(n){System.out.print("请输入要更改的学生姓名：");Scanner a=new Scanner(System.in);String name=a.next();sta = con.createStatement();String sql="select * from student";rs=sta.executeQuery(sql);//执行sql语句while(rs.next()){int m=name.compareTo(rs.getString(1));if(m==0){y=1;}}if(y==0){System.out.println("该用户名不存在，请重新输入");continue;}System.out.println("您要修改该学生的");System.out.println("1.姓名");System.out.println("2.性别");System.out.println("3.地址");System.out.println("4.专业");System.out.println("5.专业成绩");int choose=a.nextInt();String Sql;if(choose==1){System.out.print("将姓名修改为：");String news=a.next();Sql="update student 9 as 9 set name = ? where name = ? ";ps = con.prepareStatement(Sql);ps.setObject(1, news);ps.setObject(2, name);ps.execute();n=false;System.out.println("修改成功！");}else if(choose==2){System.out.print("将性别修改为：");String news=a.next();Sql="update student set sex=? where name=?";ps = con.prepareStatement(Sql);ps.setObject(1, news);ps.setObject(2, name);ps.execute();n=false;System.out.println("修改成功！");}else if(choose==3){System.out.print("将地址修改为：");String news=a.next();Sql="update student set site=? where name=?";ps = con.prepareStatement(Sql);ps.setObject(1, news);ps.setObject(2, name);ps.execute();n=false;System.out.println("修改成功！");}else if(choose==4){System.out.print("将专业修改为：");String news=a.next();Sql="update student set major=? where name=?";ps = con.prepareStatement(Sql);ps.setObject(1, news);ps.setObject(2, name);ps.execute();n=false;System.out.println("修改成功！");}else if(choose==5){System.out.print("将专业成绩修改为：");float news=a.nextFloat();Sql="update student set majorgrade=? where name=?";ps = con.prepareStatement(Sql);ps.setObject(1, news);ps.setObject(2, name);ps.execute();n=false;System.out.println("修改成功！");}}}public static void group() throws Exception					  //降序查询成绩{Connection con = null;Statement sta = null;ResultSet rs = null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");sta = con.createStatement();System.out.println("1.查看全部学生信息");System.out.println("2.查看前三名学生信息");String Sql=null;Scanner a=new Scanner(System.in);int choose=a.nextInt();if(choose==1)Sql="select * from student ORDER BY majorgrade DESC";if(choose==2)Sql="select * from student order by majorgrade asc limit 0,3";rs=sta.executeQuery(Sql);//执行sql语句System.out.println("学生姓名\t学生性别\t学生专业成绩");while(rs.next()){System.out.println(rs.getString(1)+"\t"+rs.getString(2)+"\t"+rs.getString(5));}}public static void go() throws Exception                       //进入系统{while(true){clear();System.out.println("1.增加学生信息");System.out.println("2.删除学生信息");System.out.println("3.修改学生信息");System.out.println("4.学生成绩表");System.out.println("0.查看学生信息");System.out.println("5.退出程序");int choose;Scanner a=new Scanner(System.in);clear();switch(choose=a.nextInt()){case 1:add();break;case 2:delete();break;case 3:updata();break;case 4:group();break;case 0:alldata();break;case 5:System.exit(-1);default:System.out.println("未找到该功能，请重新输入");break;}jumplong();}}public static int get(String username,String password) throws Exception//账号密码核对{Connection con = null;Statement sta = null;ResultSet rs = null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");sta = con.createStatement();String sql="select * from register";rs=sta.executeQuery(sql);//执行sql语句while(rs.next()){int a=username.compareTo(rs.getString(1));int b=password.compareTo(rs.getString(2));if(a==0&&b==0)return 1;else if(a==0&&b!=0)return 2;}return 0;}public static void enroll() throws Exception                      //登录{Scanner s=new Scanner(System.in);System.out.print("请输入账号：");String user=s.next();System.out.print("请输入密码：");String word=s.next();int w=get(user,word);if(w==1){System.out.println("登录成功！");jumpshort();go();}else if(w==2)System.out.println("密码有误，请重新输入");elseSystem.out.println("该用户不存在");}public static boolean check1(String name1) throws Exception	       //用户姓名查重{Connection con = null;Statement sta = null;ResultSet rs = null;Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");sta = con.createStatement();String sql="select * from register";rs=sta.executeQuery(sql);//执行sql语句while(rs.next()){int a=name1.compareTo(rs.getString(1));if(a==0){System.out.println("该用户名已存在，请重新输入");return true;}}return false;}public static void logon() throws Exception                        //注册{Connection con = null;Statement sta = null;PreparedStatement ps=null;try {Class.forName("com.mysql.cj.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sys?&useSSL=false&serverTimezone=UTC","root","zck12121");Scanner a=new Scanner(System.in);boolean n=true;String newname = null;while(n){System.out.print("请输入您的ID：");newname=a.next();n=check1(newname);}System.out.print("请输入您的密码：");String newword=a.next();String sql="insert into register(username,password)values(?,?)";ps = con.prepareStatement(sql);ps.setString(1,newname);ps.setString(2,newword);ps.execute();} catch (Exception e) {// TODO 自动生成的 catch 块e.printStackTrace();}finally {ps.close();con.close();}System.out.println("注册成功！");}public static void welcome() throws Exception					  //初始界面{System.out.println("欢迎进入学生管理系统");jumplong();clear();while(true){System.out.println("1.登录");System.out.println("2.注册");Scanner a=new Scanner(System.in);int choose=a.nextInt();if(choose==1)enroll();else if(choose==2)logon();elseSystem.out.println("没有该选项，请重新输入");jumplong();clear();}}public static void main(String[] args) throws Exception{welcome();}
}

案例二

package Demo04;import java.sql.*;
import java.util.*;public class mainconnection {public static void main(String[] args) {System.out.println("   ---------------------");System.out.println("    --数据库连接成功！！--");System.out.println("   ---------------------");menu();}//数据库连接public static Connection TheSqlconnection() {Connection con=null;try {//加载驱动程序Class.forName("com.mysql.jdbc.Driver");//连接MySQLcon = DriverManager.getConnection("jdbc:mysql://localhost:3306/demo02?serverTimezone=GMT","root","748294");} catch (ClassNotFoundException e) {e.printStackTrace();			} catch (SQLException e) {e.printStackTrace();}return con;}//登录private static void register() {Scanner sc = new Scanner(System.in);System.out.println("******************************");System.out.println("*        1.注册              *");System.out.println("*        2.登录              *");System.out.println("*        0.返回              *");System.out.println("******************************");System.out.println("                              ");System.out.println("请输入你的选择：              ");int num=sc.nextInt();sc.nextLine();if(num==1){System.out.println("请输入用户名：  ");String a=sc.nextLine(); System.out.println("请输入密码：    ");String b=sc.nextLine();System.out.println("注册成功！！！");System.out.println("---------------");while(true){System.out.println("**********************");System.out.println("*      1.登录        *");System.out.println("*      0.返回        *");System.out.println("**********************");System.out.println("请输入你的选择： ");int x=sc.nextInt();sc.nextLine();if(x==1){System.out.println("请输入用户名：  ");String c=sc.nextLine();if(a.equals(c)){System.out.println("请输入密码：    ");String d=sc.nextLine();if(b.equals(d)){System.out.println("密码正确！！！");}else{System.out.println("密码错误！！！");System.out.println("请重新输入密码： ");d=sc.nextLine();if(b.equals(d)){System.out.println("密码正确！！！");}else{System.out.println("密码再次错误  即将离开该页面！！！");System.exit(0); }}}else{System.out.println("用户名输入错误！！     已离开该页面");System.out.println("---------------");menu(); }	}if(x==0){System.out.println("成功返回！！"); System.out.println("---------------");menu();}break;	} 	}else if(num==2){System.out.println("尚未注册  无法登录！！！");System.out.println("如想登陆  请前往注册！！！");System.out.println("---------------");register();}else if(num==0){System.out.println("成功返回！！！");System.out.println("---------------");menu();}return ;}//主菜单public static void menu() {TheSqlconnection();Scanner sm=new Scanner(System.in); System.out.println("*************************************");System.out.println("--         学生管理系统          --");System.out.println("************************************");System.out.println("            1.管理员                                   ");System.out.println("            2.学生                                       ");System.out.println("            0.退出                                       ");System.out.println("*************************************");System.out.println("请输入你的选择");int m=sm.nextInt();if(m==1) {menu1();}else if(m==2) {menu2();}else if(m==0) {System.out.println("------------------");System.out.println("--已退出  请勿操作--");System.out.println("------------------");System.exit(0);}else {System.out.println("----输入错误   将重复此操作：");menu();}}//管理员菜单public static void menu1() {register();for(int i=0;i<1000;i++) {Scanner sc=new Scanner(System.in);System.out.println("   **************************************");System.out.println("   --        管理员 你好                 ");System.out.println("   **************************************");System.out.println("***       1.增加学生信息                ***");System.out.println("***       2.删除学生信息                ***");System.out.println("***       3.查询学生信息                ***");System.out.println("***       4.更新学生信息                ***");System.out.println("***       5.分页查询学生信息          ***");System.out.println("***       6.分组排序学生信息          ***");			System.out.println("***       7.显示学生信息                ***");			System.out.println("***       0.返回                        ***");System.out.println("*****************************************");System.out.println("请输入你的选择");int x=sc.nextInt();switch(x) {case 1:add();break;case 2:del();break;case 3:search();break;case 4:update();break;case 5:pages();break;	case 6:order();break;	case 7:print();break;case 0:menu();break;default:System.out.println("---输入错误 请重新输入！！！");menu1();break;}}}//学生菜单public static void menu2() {for(int b=0;b<500;b++) {Scanner cc=new Scanner(System.in);System.out.println("***********************");System.out.println("            学生     你好             ");System.out.println("***********************");System.out.println("      1.查询信息                  ");System.out.println("      2.显示信息                  ");System.out.println("      0.返回                         ");System.out.println("***********************");int t=cc.nextInt();switch(t) {case 1:search();break;case 2:print();break;case 0:menu();break;default:System.out.println("输入错误  请重新输入：");menu2();break;}}}//增加private static void add() {String sql="insert into student value(?,?,?,?)";Connection con = TheSqlconnection();Scanner cc=new Scanner(System.in);try {System.out.println("------------------------");System.out.println("请输入你要添加的学生个数：");System.out.println("------------------------");int n=cc.nextInt();for(int p=1;p<=n;p++) {System.out.println("请输入学生学号：");int id=cc.nextInt();System.out.println("请输入学生姓名：");cc.nextLine();String name=cc.nextLine();System.out.println("请输入学生性别：");String sex=cc.nextLine();System.out.println("请输入学生成绩：");int grade=cc.nextInt();PreparedStatement ps = con.prepareStatement(sql);//设置SQL语句里的参数ps.setInt(1,id);ps.setString(2,name);ps.setString(3,sex);ps.setInt(4,grade);int rows=ps.executeUpdate();if(rows>0) {System.out.println("第"+p+"个学生信息添加成功！！");System.out.println("============================");}}}catch(SQLException e) {e.printStackTrace();  }		}//删除private static void del() {Connection con = TheSqlconnection();Scanner cc=new Scanner(System.in);		try {   		System.out.println("请输入想要删除的学生学号：");int id=cc.nextInt();String sql="delete from student where id="+id;PreparedStatement ps = con.prepareStatement(sql);int rows=ps.executeUpdate();if(rows>0) {System.out.println("删除学生信息成功！！");System.out.println("============================");}else {System.out.println("删除学生信息失败！！");}}catch(SQLException e) {e.printStackTrace();  }  			}//查询private static void search() {Connection con = TheSqlconnection();Scanner cc=new Scanner(System.in);   	try {    		String sql="select * from student where id=?";    		PreparedStatement ps = con.prepareStatement(sql);	        System.out.println("请输入想要查询的学生学号：");int id=cc.nextInt();ps.setInt(1,id);						ResultSet rs = ps.executeQuery();if(rs.next()) {String name=rs.getString("name");String sex=rs.getString("sex");int grade=rs.getInt("grade");   System.out.println("查询结果如下：");System.out.println("============================");System.out.println("id"+"\t"+"姓名"+"\t"+"性别"+"\t"+"成绩"); System.out.println(id+"\t"+name+"\t"+sex+"\t"+grade);System.out.println("============================");System.out.println("查询学生信息成功！！");System.out.println("============================");}rs.close();con.close();}catch(SQLException e) {System.out.println("查询学生信息失败！！");e.printStackTrace();  }		}//更新private static void update() {Connection con = TheSqlconnection();Scanner cc=new Scanner(System.in);  	try {   				System.out.println("请输入想要更新的学生学号：");int id=cc.nextInt();System.out.println("请输入想要更新的学生姓名：");cc.nextLine();String name=cc.nextLine();System.out.println("请输入想要更新的学生性别：");String sex=cc.nextLine();System.out.println("请输入想要更新的学生成绩：");int grade=cc.nextInt();String sql="update student set name=?,sex=?,grade=? where id=?";PreparedStatement ps = con.prepareStatement(sql);ps.setString(1,name);ps.setString(2,sex);ps.setInt(3,grade);ps.setInt(4,id);ps.executeUpdate();System.out.println("更新学生信息成功！！");System.out.println("============================");ps.close();}catch(SQLException e) {System.out.println("更新学生信息失败！！");e.printStackTrace(); }   	}//分页查询private static void pages() {Scanner cc=new Scanner(System.in);Connection con = TheSqlconnection();   	System.out.println("每页显示五条记录    请问你想查询哪一页(请输入大于等于1的整数)：");int num=cc.nextInt(); int start=0;int count=5;try {Statement ps = con.createStatement();   		   		if (num==1) {start = 0;        }else{if (num<1) {   System.out.println("输入错误！ 无法查询");   				System.out.println("=====================");   				       			}else {start = (num-1)*5;           }       }   String sql = "select * from student order by id asc limit "+ start + "," + count;   	   	ResultSet rs = ps.executeQuery(sql);System.out.println("id"+"\t"+"姓名"+"\t"+"性别"+"\t"+"成绩");  System.out.println("----------------------------");   while(rs.next()){  int id = rs.getInt(1);  String name = rs.getString(2);  String sex = rs.getString(3);  int grade = rs.getInt(4); 			System.out.println(id+"\t"+name+"\t"+sex+"\t"+grade);  			}   		  		}catch(SQLException e){                      e.printStackTrace();   		}   	}//分组排序private static void order() {Scanner cc=new Scanner(System.in);Connection con = TheSqlconnection();System.out.println("=====================");System.out.println("        1.升序     ");  System.out.println("        2.降序     ");   System.out.println("=====================");       System.out.println("请选择排序的方式：");int a=cc.nextInt();if(a==1) {try {   			String sql="select * from student order by grade asc)";Statement stmt = con.createStatement();ResultSet rs = stmt.executeQuery(sql); //用来存放获取的结果集System.out.println("----------------------------");System.out.println("升序结果如下：");  System.out.println("----------------------------");  System.out.println("id"+"\t"+"姓名"+"\t"+"性别"+"\t"+"成绩");  System.out.println("----------------------------");Integer id = null;String name = null;String sex = null;Integer grade = null;    	//rs.next()返回值为布尔型while(rs.next()){id = rs.getInt("id");name = rs.getString("name");sex = rs.getString("sex");grade = rs.getInt("grade");    				System.out.println(id + "\t" + name+ "\t" + sex+ "\t" + grade);    			}rs.close();con.close();   			}catch(SQLException e){                      e.printStackTrace();   }    	  }else if(a==2) {try {String sql="select * from student order by grade desc";Statement stmt = con.createStatement();ResultSet rs = stmt.executeQuery(sql); //用来存放获取的结果集System.out.println("----------------------------");System.out.println("降序结果如下：");  System.out.println("----------------------------");  System.out.println("id"+"\t"+"姓名"+"\t"+"性别"+"\t"+"成绩");  System.out.println("----------------------------");Integer id = null;String name = null;String sex = null;Integer grade = null;   	//rs.next()返回值为布尔型while(rs.next()){   				id = rs.getInt("id");name = rs.getString("name");sex = rs.getString("sex");grade = rs.getInt("grade");   				System.out.println(id + "\t" + name+ "\t" + sex+ "\t" + grade);   			}rs.close();con.close();    			}catch(SQLException e){      e.printStackTrace();   }    	          	}}//显示private static void print() {String sql = "select * from student";//定义SQL语句	Connection con = TheSqlconnection();try {Statement stmt = con.createStatement();ResultSet rs = stmt.executeQuery(sql); //用来存放获取的结果集System.out.println("----------------------------");System.out.println("数据库内容如下所示：");  System.out.println("----------------------------");  System.out.println("id"+"\t"+"姓名"+"\t"+"性别"+"\t"+"成绩");  System.out.println("----------------------------");Integer id = null;String name = null;String sex = null;Integer grade = null;//rs.next()返回值为布尔型while(rs.next()){id = rs.getInt("id");name = rs.getString("name");sex = rs.getString("sex");grade = rs.getInt("grade");System.out.println(id + "\t" + name+ "\t" + sex+ "\t" + grade);}rs.close();con.close();}catch(SQLException e){      e.printStackTrace();   }    	  }}

案例三

JDBCUtils.java

package vb.itcast.util;import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.*;
import java.util.Properties;public class JDBCUtils {private static  String url;private static  String username;private static  String password;private static  String driver;static {try {Properties pro =new Properties();//类加载器ClassLoader classLoader = JDBCUtils.class.getClassLoader();URL res = classLoader.getResource("jdbc.properties");String path = res.getPath();System.out.println(res);//    pro.load(new FileReader("src/jdbc.properties"));pro.load(new FileReader(path));url=pro.getProperty("url");username=pro.getProperty("username");password=pro.getProperty("password");driver=pro.getProperty("driver");Class.forName(driver);} catch (IOException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();}}public static Connection getconnection() throws SQLException {return DriverManager.getConnection(url,username,password);}
//    Class.forName("com.mysql.cj.jdbc.Driver");
//    String url = "jdbc:mysql://localhost:3306/runnoob?&useSSL=false&serverTimezone=UTC" ;
//    String username = "root" ;
//    String password = "root" ;public static void close(ResultSet rs, Statement stmt,Connection conn){if (rs!=null) {try {rs.close();} catch (SQLException e) {e.printStackTrace();}}if (stmt!=null) {try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}if (conn!=null) {try {conn.close();} catch (SQLException e) {e.printStackTrace();}}
}public static void close(Statement stmt,Connection conn){if( stmt != null){try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}if( conn != null){try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}public class zxc{public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getUrl() {return url;}public void setUrl(String url) {this.url = url;}public int getAlexa() {return alexa;}public void setAlexa(int alexa) {this.alexa = alexa;}public String getCountry() {return country;}public void setCountry(String country) {this.country = country;}private int id;private String name;private String url;private int alexa;private String country;@Overridepublic String toString() {return "zxc{" +"id=" + id +", name='" + name + '\'' +", url='" + url + '\'' +", alexa=" + alexa +", country='" + country + '\'' +'}';}
}}

JDBCDemo9.java

package vb.itcast.jdbc;import vb.itcast.util.JDBCUtils;import java.sql.*;
import java.util.Scanner;public class JDBCDemo9 {public static void main(String[] args) {System.out.println("是否注册Y/N");Scanner sc = new Scanner(System.in);;if (sc.nextLine().equals("Y")) {registered();}System.out.println("登录");System.out.println("请输入用户名");String username = sc.nextLine();System.out.println("请输入密码");String password = sc.nextLine();boolean flag = new JDBCDemo9().login(username, password);if (flag) {System.out.println("登录成功");} else {System.out.println("用户名或密码错误");}while (flag) {System.out.println("---------------------------------------------------------------");System.out.println("按1添加信息");System.out.println("按2删除信息");System.out.println("按3查找信息");System.out.println("按4修改信息");System.out.println("按5分组排序");System.out.println("按6分页查询");System.out.println("按0退出");System.out.println("---------------------------------------------------------------");int ch = sc.nextInt();switch (ch) {case 1:insert();break;case 2:delete();break;case 3:select();break;case 4:update();break;case 5:order();break;case 6:limit();break;case 0:flag=false;System.out.println("bye bye");break;default:System.out.println("无此选项请重新输入");}}}public boolean login(String username, String password) {if (username == null && password == null) {return false;}String sql = "select * from user where username=? and password=?";Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);pstmt.setString(1, username);pstmt.setString(2, password);rs = pstmt.executeQuery();return rs.next();} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtils.close(rs, pstmt, conn);}return false;}static void registered() {Scanner sc = new Scanner(System.in);Connection conn = null;PreparedStatement pstmt = null;try {String sql = "insert into user values (null ,?,?)";conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);System.out.println("输入账号");pstmt.setString(1, sc.next());System.out.println("输入密码");pstmt.setString(2, sc.next());int count = pstmt.executeUpdate();if (count > 0) {System.out.println("注册成功");} elseSystem.out.println("注册失败");} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtils.close(pstmt, conn);}}static void insert() {Scanner sc = new Scanner(System.in);Connection conn = null;PreparedStatement pstmt = null;String sql = "insert into websites values (null ,?,?,?,?)";try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);System.out.println("输入名称");pstmt.setString(1, sc.next());System.out.println("输入地址");pstmt.setString(2, sc.next());System.out.println("输入alexa");pstmt.setString(3, sc.next());System.out.println("输入地区");pstmt.setString(4, sc.next());int count = pstmt.executeUpdate();if (count > 0) {System.out.println("添加成功");} else {System.out.println("添加失败");}} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtils.close(pstmt, conn);}}static void delete() {Scanner sc = new Scanner(System.in);Connection conn = null;PreparedStatement pstmt = null;String sql = "delete from websites where id=?";try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);System.out.println("请输入要删除的ID");pstmt.setString(1, sc.next());int count = pstmt.executeUpdate();if (count > 0) {System.out.println("删除成功");} else {System.out.println("删除失败");}} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtils.close(pstmt, conn);}}static void select(){Scanner sc = new Scanner(System.in);Connection conn = null;PreparedStatement pstmt = null;ResultSet rs=null;String sql = "select *from websites where id=?";try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);System.out.println("请输入要查询的ID");pstmt.setString(1, sc.next());rs=pstmt.executeQuery();while (rs.next()){int id=rs.getInt("id");String name = rs.getString("name") ;String pass = rs.getString("url") ;String country=rs.getString("country");int alexa = rs.getInt("alexa");System.out.println(id+" "+name+" "+pass+" "+country+" "+alexa);}//           if (rs.next()) {
//                System.out.println("查询成功");
//            } else {
//                System.out.println("查询失败");
//            }} catch (SQLException e) {e.printStackTrace();}finally {JDBCUtils.close( rs,pstmt, conn);}}static void update(){Scanner sc = new Scanner(System.in);Connection conn = null;PreparedStatement pstmt = null;String sql = "update  websites set name =?,url=?,alexa=?,country=? where id=?";try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);System.out.println("请输入要修改的ID");pstmt.setString(5,sc.next());System.out.println("输入名称");pstmt.setString(1, sc.next());System.out.println("输入地址");pstmt.setString(2, sc.next());System.out.println("输入alexa");pstmt.setString(3, sc.next());System.out.println("输入地区");pstmt.setString(4, sc.next());int count = pstmt.executeUpdate();if (count > 0) {System.out.println("修改成功");} else {System.out.println("修改失败");}} catch (SQLException e) {e.printStackTrace();} finally {JDBCUtils.close(pstmt, conn);}}static void order(){Connection conn = null;PreparedStatement pstmt = null;ResultSet rs=null;String sql = "select  country,SUM(alexa) FROM websites group by country order by SUM(alexa) desc  ";try {conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);rs=pstmt.executeQuery();while (rs.next()){String country=rs.getString("country");int alexa = rs.getInt(2);System.out.println(country+" "+alexa);}} catch (SQLException e) {e.printStackTrace();}finally {JDBCUtils.close( rs,pstmt, conn);}}static int page=1;static void limit(){Scanner sc = new Scanner(System.in);Connection conn =null;PreparedStatement pstmt =null;ResultSet  rs=null;String sql="select *from websites limit ?,?";try {System.out.println("请输入每页显示条数");int size=sc.nextInt();conn = JDBCUtils.getconnection();pstmt = conn.prepareStatement(sql);// System.out.println("请输入起始号");pstmt.setInt(1,(page-1)*size);pstmt.setInt(2,size);rs=pstmt.executeQuery();while (rs.next()){int id=rs.getInt("id");String name = rs.getString("name") ;String pass = rs.getString("url") ;String country=rs.getString("country");int alexa = rs.getInt("alexa");System.out.println(id+" "+name+" "+pass+" "+country+" "+alexa);}page++;} catch (SQLException e) {e.printStackTrace();}finally {JDBCUtils.close(rs,pstmt,conn);}}}

websites.sql

/*Navicat Premium Data TransferSource Server         : localhost_3306Source Server Type    : MySQLSource Server Version : 80019Source Host           : localhost:3306Source Schema         : runnoobTarget Server Type    : MySQLTarget Server Version : 80019File Encoding         : 65001Date: 26/04/2020 23:53:01
*/SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;-- ----------------------------
-- Table structure for websites
-- ----------------------------
DROP TABLE IF EXISTS `websites`;
CREATE TABLE `websites`  (`id` int(0) NOT NULL AUTO_INCREMENT,`name` char(20) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '' COMMENT '站点名称',`url` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '',`alexa` int(0) NOT NULL DEFAULT 0 COMMENT 'Alexa 排名',`country` char(10) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '' COMMENT '国家',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 27 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of websites
-- ----------------------------
INSERT INTO `websites` VALUES (1, 'Google', 'https://www.google.cm/', 1, 'USA');
INSERT INTO `websites` VALUES (2, '淘宝', 'https://www.taobao.com/', 13, 'CN');
INSERT INTO `websites` VALUES (3, '菜鸟教程', 'http://www.runoob.com', 5892, 'CN');
INSERT INTO `websites` VALUES (4, '微博', 'http://weibo.com/', 20, 'CN');
INSERT INTO `websites` VALUES (5, 'Facebook', 'https://www.facebook.com/', 3, 'USA');
INSERT INTO `websites` VALUES (6, '2', '2', 2, '2');
INSERT INTO `websites` VALUES (7, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (8, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (9, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (10, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (11, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (12, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (13, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (14, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (15, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (16, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (17, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (18, '1', '1', 1, '1');
INSERT INTO `websites` VALUES (19, 'country', '1', 1, '1');
INSERT INTO `websites` VALUES (20, '11', '22', 33, '1');
INSERT INTO `websites` VALUES (21, '汤不热', 'www.buzhidao.com', 2123, '米国');
INSERT INTO `websites` VALUES (22, '3', '3', 0, 'UK');
INSERT INTO `websites` VALUES (23, '3', '3', 0, 'UK');
INSERT INTO `websites` VALUES (24, '3', '3', 0, 'UK');
INSERT INTO `websites` VALUES (25, '3', '3', 0, 'UK');
INSERT INTO `websites` VALUES (30, '3', '3', 0, 'UK');
INSERT INTO `websites` VALUES (31, '1', '1', 1, '1');SET FOREIGN_KEY_CHECKS = 1;

user.sql

/*Navicat Premium Data TransferSource Server         : localhost_3306Source Server Type    : MySQLSource Server Version : 80019Source Host           : localhost:3306Source Schema         : runnoobTarget Server Type    : MySQLTarget Server Version : 80019File Encoding         : 65001Date: 26/04/2020 23:53:30
*/SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (`id` int(0) NOT NULL AUTO_INCREMENT,`username` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,`PASSWORD` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL,PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (1, 'zhangsan', '123');
INSERT INTO `user` VALUES (2, 'lisi', '234');
INSERT INTO `user` VALUES (3, 'lisi', '345');
INSERT INTO `user` VALUES (4, '111', '111');
INSERT INTO `user` VALUES (5, 'wangwu', '123456');
INSERT INTO `user` VALUES (6, '111', '111');SET FOREIGN_KEY_CHECKS = 1;

jdbc.properties

url = jdbc:mysql://localhost:3306/runnoob?&useSSL=false&serverTimezone=UTC
username = root
password = root
driver =com.mysql.cj.jdbc.Driver

案例四

package com.itcast;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;public class StudentJDBC {private static Scanner sc=new Scanner(System.in);//注册public static void login() {System.out.println("");String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";Scanner sc=new Scanner(System.in);System.out.print("请输入你的注册用户名：");String uname=sc.next();System.out.print("请输入你的注册密码：");String upwd=sc.next();String sql="insert into login (uname,upwd) values (?,?)";Connection con=null;PreparedStatement ps=null;try {Class.forName("com.mysql.jdbc.Driver");con=DriverManager.getConnection(url, user, password);ps=con.prepareStatement(sql);ps.setString(1, uname);ps.setString(2,upwd);int row=ps.executeUpdate();if(row>0) {System.out.println("注册成功！");}else {System.out.println("注册失败！");}}catch(ClassNotFoundException e) {e.printStackTrace();}catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(ps!=null) {ps.close();}}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//登录public static void register() {Connection con=null;PreparedStatement ps=null;ResultSet rs=null;Scanner sc=new Scanner(System.in);System.out.print("请输入你的登陆用户名：");String uname=sc.next();System.out.print("请输入你的登陆密码：");String upwd=sc.next();try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);String sql="select count(*) from login where uname=? and upwd=?";ps=con.prepareStatement(sql);ps.setString(1, uname);ps.setString(2,upwd);rs=ps.executeQuery();if(rs.next()) {int count=rs.getInt(1);if(count==0) {System.out.println("登陆失败！");}else {System.out.println("登陆成功！");}}}catch(ClassNotFoundException e) {e.printStackTrace();}catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(ps!=null) ps.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}public static void main(String[] args) {login();register();System.out.println("欢迎使用学生信息管理系统！");while(true) {System.out.print("1:查询学生信息  ");System.out.print("2:添加学生信息  ");System.out.print("3:修改学生信息  ");System.out.print("4:删除学生信息  ");System.out.print("5.分组排序  "); System.out.println("6.分页查看  ");System.out.print("请输入你要进行的操作：");//接受用户输入的操作选项String opt = sc.next();if(opt.equals("1")) {//查询学生信息findAll();}else if(opt.equals("2")) {//添加学生信息addStu();}else if(opt.equals("3")) {//修改学生信息updateStu();}else if(opt.equals("4")) {//删除学生信息deleteStu();	}else if(opt.equals("5")) {//删除学生信息order();}else if(opt.equals("6")) {//删除学生信息findpage();	}else {System.out.println("输入错误！请重新输入...");}}}//查询所有的学生信息，直接打印在控制台private static void findAll(){Connection con=null;Statement stmt=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);stmt=con.createStatement();rs=stmt.executeQuery("select * from stu");//列的索引从1开始while(rs.next()) {System.out.println(rs.getInt(1)+","+rs.getString(2)+","+rs.getString(3)+","+rs.getInt(4));}System.out.println("=========================");}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(stmt!=null) stmt.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//添加学生信息private static void addStu() {System.out.println("请输入要添加的学生编号、姓名、性别、成绩(以空格分隔)：");//获取用户输入的学生信息int id=sc.nextInt();String name=sc.next();String gender=sc.next();double score=sc.nextDouble();Connection con=null;PreparedStatement ps=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);//获取传输器，执行SQL语句String sql="insert into stu value(?,?,?,?)";ps=con.prepareStatement(sql);//设置SQl语句中的参数ps.setInt(1,id);ps.setString(2, name);ps.setString(3,gender);ps.setDouble(4, score);//执行sql语句int rows=ps.executeUpdate();//不要二次传入SQLif(rows>0) {System.out.println("学生信息添加成功！");System.out.println("=========================");}}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(ps!=null) ps.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//修改学生信息private static void updateStu() {System.out.println("请输入要修改的学生编号、姓名、性别、成绩(以空格分隔)：");int id=sc.nextInt();String name=sc.next();String gender=sc.next();double score=sc.nextDouble();Connection con=null;PreparedStatement ps=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);//获取传输器，执行SQL语句String sql="update stu set name=?,gender=?,score=? where id=?";ps=con.prepareStatement(sql);//设置SQL语句中的参数ps.setString(1, name);ps.setString(2,gender);ps.setDouble(3, score);ps.setInt(4,id);//执行SQl语句int rows=ps.executeUpdate();if(rows>0) {System.out.println("学生信息修改成功!");System.out.println("=========================");}}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(ps!=null) ps.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//删除学生信息private static void deleteStu() {System.out.println("请输入要删除的学生编号：");int id=sc.nextInt();Connection con=null;PreparedStatement ps=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);//获取传输器，执行SQL语句String sql="delete from stu where id=?";ps=con.prepareStatement(sql);//设置SQl语句的参数ps.setInt(1, id);//执行SQL语句int rows=ps.executeUpdate();if(rows>0) {System.out.println("学生信息删除成功!");System.out.println("=========================");}}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(ps!=null) ps.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//分组排序private static void order() {Connection con=null;Statement stmt=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);//获取传输器，执行SQL语句stmt=con.createStatement();rs=stmt.executeQuery("select * from (select * from stu order by gender desc limit 999999 ) a group by a.score");//设置SQl语句的参数//执行SQL语句while(rs.next()) {System.out.println(rs.getInt(1)+","+rs.getString(2)+","+rs.getString(3)+","+rs.getInt(4));}System.out.println("=========================");}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(stmt!=null) stmt.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}//分页查询/*	@param page   页数*/private static void findpage() {Connection con=null;Statement stmt=null;ResultSet rs=null;try {//注册驱动并获取连接Class.forName("com.mysql.jdbc.Driver");//使用什么驱动连接数据库String url="jdbc:mysql://localhost:3306/jt_db?useUnicode=true&characterEncoding=UTF8&useSSL=false";String user="root";String password="123456";con=DriverManager.getConnection(url, user, password);stmt=con.createStatement();rs=stmt.executeQuery("select * from stu where id<100 order by id asc limit 0,10");//列的索引从1开始while(rs.next()) {System.out.println(rs.getInt(1)+","+rs.getString(2)+","+rs.getString(3)+","+rs.getInt(4));}System.out.println("=========================");}catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {//释放资源try {if(rs!=null) rs.close();}catch(SQLException e){e.printStackTrace();}try {if(stmt!=null) stmt.close();}catch(SQLException e){e.printStackTrace();}try {if(con!=null) con.close();}catch(SQLException e){e.printStackTrace();}}}}

案例五

package student;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;public class studentss {public static void main(String[] args) throws Exception {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.println("********用户界面********");System.out.println("请选择：\n 1:用户登录\n 2:用户注册");System.out.println("**********************");int i=in.nextInt();switch(i) {case 1:login();break;case 2:register();break;default:System.out.println("输入有误!");System.exit(0);}int j;for(j=0;j<1000;j++) {menu();System.out.println("请输入你想实现的功能所对应的序号:");int a=in.nextInt();switch(a) {case 1:add();break;case 2:update();break;case 3:delete();break;case 4:select();break;case 5:print();break;case 6:select_1();break;case 7:select_2();break;case 8:select_3();break;}} }private static void print() {String sql="select * from students";Connection conn =SqlConnection();try {Statement a=conn.createStatement();ResultSet rs=a.executeQuery(sql);System.out.println("————————————————————————————————");System.out.println("数据库显示内容如下:");System.out.println("————————————————————————————————");System.out.println("id"+"  "+"姓名"+"  "+"性别"+"  "+"成绩");System.out.println("———————————————————————————————");Integer id =null;String name=null;String ssex=null;Integer grade=null;while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");ssex=rs.getString("ssex");grade=rs.getInt("grade");System.out.println(id+" "+name+"   "+ssex+"     "+grade);}rs.close();conn.close();}catch(SQLException e) {e.printStackTrace();}}private static void menu(){System.out.println("***************************************************");System.out.println("*********\t学生信息管理系统\t********");System.out.println("********\t1.增加学生信息\t***********");System.out.println("********\t2.更新学生信息\t***********");System.out.println("********\t3.删除学生信息\t***********");System.out.println("********\t4.查询学生信息\t***********");System.out.println("********\t5.打印学生信息\t***********");System.out.println("********\t6.分组查询学生信息(降序)\t***********");System.out.println("********\t7.分组查询学生信息(升序)\t***********");System.out.println("********\t8.分页查询学生信息\t***********");}private static void add(){String sql="insert into students values(?,?,?,?)";Connection conn =SqlConnection();Scanner in=new Scanner(System.in);try {System.out.println("————————————————————————————");System.out.println("请输入你要添加的学生个数:");System.out.println("—————————————————————————————");int j=in.nextInt();for(int i=0;i<j;i++) {System.out.println("请输入学生学号:");int id=in.nextInt();System.out.println("请输入学生姓名:");in.nextLine();String name=in.nextLine();System.out.println("请输入学生性别:");String ssex=in.nextLine();System.out.println("请输入学生成绩:");int grade=in.nextInt();PreparedStatement ps =conn.prepareStatement(sql);ps.setInt(1, id);ps.setString(2, name);ps.setString(3,ssex);ps.setInt(4, grade);int rows=ps.executeUpdate();if(rows>0) {System.out.println("添加成功!");}}}catch(SQLException e) {e.printStackTrace();}}public static void delete() {String sql="delete from students where id=?";Scanner in=new Scanner(System.in);Connection conn =SqlConnection();try {PreparedStatement ps =conn.prepareStatement(sql);System.out.println("——————————————————————————————————");System.out.println("请输入你想要删除的学生的学号:");int id=in.nextInt();ps.setInt(1, id);int a=ps.executeUpdate();if(a>0) {System.out.println("删除成功!");}}catch(SQLException e) {e.printStackTrace();System.out.println("删除失败!");}}public static  void select() throws SQLException{Connection conn =SqlConnection();Scanner in=new Scanner(System.in);String sql="select name,ssex,grade from students where id=?";PreparedStatement ps =conn.prepareStatement(sql);System.out.println("请输入你想要查询的学生所对应的学号:");int id=in.nextInt();ps.setInt(1,id);ResultSet rs=ps.executeQuery();while(rs.next()) {String name=rs.getString("name");String ssex=rs.getString("ssex");int grade=rs.getInt("grade");System.out.println(name+" "+ssex+" "+grade);}rs.close();ps.close();conn.close();}public static void update() {System.out.println("请输入要更新的学生学号:");Scanner in=new Scanner(System.in);int id=in.nextInt();System.out.println("请输入要更新的学生姓名:");String name=in.next();System.out.println("请输入要更新的学生性别:");String ssex=in.next();System.out.println("请输入要更新的学生成绩:");int grade=in.nextInt();try {Connection conn=SqlConnection();String sql="update students set name=?,ssex=?,grade=? where id=?";PreparedStatement ps=conn.prepareStatement(sql);ps.setString(1, name);ps.setString(2,ssex);ps.setInt(3,grade);ps.setInt(4, id);int a=ps.executeUpdate();if(a>0) {System.out.println("学生信息修改成功!");}}catch(SQLException e) {e.getStackTrace();}}private static void select_1() {String sql="select * from students group by id,ssex order by grade desc;";Connection conn =SqlConnection();try {PreparedStatement ps=conn.prepareStatement(sql);Statement a=conn.createStatement();ResultSet rs=a.executeQuery(sql);System.out.println("————————————————————————————————");System.out.println("数据库显示内容如下:");System.out.println("————————————————————————————————");System.out.println("id"+"  "+"姓名"+"  "+"性别"+"  "+"成绩");System.out.println("———————————————————————————————");Integer id =null;String name=null;String ssex=null;Integer grade=null;ps.execute();while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");ssex=rs.getString("ssex");grade=rs.getInt("grade");System.out.println(id+" "+name+"   "+ssex+"     "+grade);}rs.close();conn.close();}catch(SQLException e) {e.printStackTrace();}}private static void select_2() {String sql="select * from students group by id,ssex order by grade asc;";Connection conn =SqlConnection();try {Statement a=conn.createStatement();ResultSet rs=a.executeQuery(sql);PreparedStatement ps=conn.prepareStatement(sql);System.out.println("————————————————————————————————");System.out.println("数据库显示内容如下:");System.out.println("————————————————————————————————");System.out.println("id"+"  "+"姓名"+"  "+"性别"+"  "+"成绩");System.out.println("———————————————————————————————");Integer id =null;String name=null;String ssex=null;Integer grade=null;ps.execute();while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");ssex=rs.getString("ssex");grade=rs.getInt("grade");System.out.println(id+" "+name+"   "+ssex+"     "+grade);}rs.close();conn.close();}catch(SQLException e) {e.printStackTrace();}}private static void select_3() {Scanner in=new Scanner(System.in);Connection conn =SqlConnection();System.out.println("每页显示六条记录，请输入你想查询的页对应的序号:");int a=in.nextInt();int b = 0;int c=6;try {Statement ps=conn.createStatement();if(a==1) {b = 0;}else {if(a<1) {System.out.println("输入错误，无法进行查询");}else {b=(a-1)*6;}}String sql="select * from students order by id asc limit "+ b +"," + c;ResultSet rs=ps.executeQuery(sql);System.out.println("学号"+" "+"姓名"+" "+"性别"+" "+"成绩");System.out.println("————————————————————————————————————————");while(rs.next()) {int id=rs.getInt(1);String name=rs.getString(2);String ssex=rs.getString(3);int grade=rs.getInt(4);System.out.println(id+" "+name+" "+ssex+" "+grade);}}catch(SQLException e) {e.printStackTrace();}}public static void register() throws SQLException{Connection conn =SqlConnection();Scanner in=new Scanner(System.in);System.out.println("请输入你的姓名:");String name=in.nextLine();System.out.println("请输入你的登陆密码:");String p1=in.next();System.out.println("请再次输入你的登陆密码:");String p2=in.next();if(p1.equals(p2)) {String password=p1;String sql="insert into user(name,password) values(?,?)";PreparedStatement pt = conn.prepareStatement(sql);pt.setString(1,name);pt.setString(2,password);pt.execute();System.out.println("注册成功!\n请登录:");login();}else {System.out.println("你输入的密码与确认密码不相同，请重新注册:");register();}}public static void login() throws SQLException{Connection conn =SqlConnection();Scanner in=new Scanner(System.in);System.out.println("请输入你的姓名:");String name=in.nextLine();System.out.println("请输入你的密码:");String password=in.next();String sql = "select name,password from user where name=? and password=?";PreparedStatement pt = conn.prepareStatement(sql);pt.setString(1, name);pt.setString(2, password);ResultSet rs = pt.executeQuery();//从给出的账号密码来检测是否有相同的账号密码if(rs.next()) {System.out.println("登陆成功!");}else {System.out.println("姓名或密码错误!\n请重新登陆:");login();}}public static Connection SqlConnection() {Connection conn=null;try {//加载MySQL驱动Class.forName("com.mysql.jdbc.Driver");System.out.println("加载驱动成功!");//连接数据库，获得连接对象conn =DriverManager.getConnection("jdbc:mysql://localhost:3306/student","root","a123456");System.out.println("数据库连接成功");// 创建执行环境/*Statement statement=conn.createStatement();// 执行sql语句，得到结果集ResultSet result = statement.executeQuery("select * from students");while(result.next()) {System.out.print(result.getInt("id")+" ");System.out.print(result.getString("name")+" ");System.out.println(result.getString("password"));}*/}catch(Exception e) {e.printStackTrace();System.out.println("驱动加载失败");System.out.println("数据库连接失败");}return conn;
}}

案例六

DBtool.java

package com.it666.jdbc.conn;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBtool {private static String driver;private static String url;private static String user;private static String password;     public static Connection open() { try {driver="com.mysql.jdbc.Driver";url="jdbc:mysql://localhost:3306/student";user="root";password="yang1234"; Class.forName(driver);//注册驱动return DriverManager.getConnection(url, user, password);//连接到数据库} catch (Exception e) {e.printStackTrace();}return null;}public static void close(Connection conn){if(conn!=null){try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}
}

Test.java

package com.it666.jdbc.conn;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;public class Test {                                     //主函数public static void main(String[]args ){@SuppressWarnings("resource")Scanner in=new Scanner(System.in);logan();boolean b=true;while(b){menu();int a=in.nextInt();switch(a) {case 1:insert();break;case 2:delete();break;case 3:query();break;case 4:update();break;case 5:show();break;case 6:rank();break;case 7:fenye();break;case 8:b=false;System.out.println("再见，谢谢您的使用");break;default:System.out.println("选择错误，请重新选择！");break;} }}static void update() {                                            //修改信息Connection conn=DBtool.open();try {@SuppressWarnings("resource")Scanner in=new Scanner(System.in);		@SuppressWarnings("resource")Scanner s=new Scanner(System.in);String sql;String sno;String sname;String ssex;String sage;  String sscore;System.out.println("请输入你那个被修改学生的学号：");sno=s.nextLine();System.out.println("请选择你要修改的信息的选项：");System.out.println("1.学号  2.姓名 3性别 4年龄 5.成绩");int a=in.nextInt();switch(a) { case 1:	 System.out.println("请输入要修改的学号");    String sno1=s.nextLine();		                 sql="update student set Sno=\""+sno1+"\"where Sno=\""+sno+"\";";		PreparedStatement pst=(PreparedStatement)conn.prepareStatement(sql);@SuppressWarnings("unused") int i=pst.executeUpdate();//System.out.println(sql);System.out.println("修改成功！");break;    case 2: System.out.println("请输入要修改的姓名");  sname=s.nextLine();			                  sql="update student set Sname=\""+sname+"\"where Sno=\""+sno+"\";"; PreparedStatement ps=(PreparedStatement)conn.prepareStatement(sql);@SuppressWarnings("unused") int j=ps.executeUpdate();//   System.out.println(j);System.out.println("修改成功");break;case 3:System.out.println("请输入要修改的性别");  ssex=s.nextLine();			                  sql="update student set Ssex=\""+ssex+"\"where Sno=\""+sno+"\";";	            	PreparedStatement p=(PreparedStatement)conn.prepareStatement(sql);@SuppressWarnings("unused") int k=p.executeUpdate();// System.out.println(k);System.out.println("修改成功");break;case 4: System.out.println("请输入要修改的年龄");  sage=s.nextLine();			                  sql="update student set Sage=\""+sage+"\"where Sno=\""+sno+"\";";	            	PreparedStatement t=(PreparedStatement)conn.prepareStatement(sql);@SuppressWarnings("unused") int l=t.executeUpdate();// System.out.println(k);System.out.println("修改成功");break;case 5:System.out.println("请输入要修改的成绩");  sscore=s.nextLine();			                  sql="update student set Stel=\""+sscore+"\"where Sno=\""+sno+"\";";	            	PreparedStatement r=(PreparedStatement)conn.prepareStatement(sql);@SuppressWarnings("unused") int m=r.executeUpdate();// System.out.println(k);System.out.println("修改成功");break;default:System.out.println("输入错误！返回主界面");break;	  }} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void menu() {                                   //菜单System.out.println("=========学生信息表==========");System.out.println("======请输入你想实现的功能：==");System.out.println("*******==1:增加信息==*********");System.out.println("*******==2:删除信息==*********");System.out.println("*******==3:查询信息==*********");System.out.println("*******==4:修改信息==*********");	System.out.println("*******==5.显示表中信息==****");System.out.println("*******==6:按性别分组排序==*********");System.out.println("*******==7:分页查询信息==*********");System.out.println("*******==8.退出==************");}static void show() {                                            //显示信息Connection conn=DBtool.open();String sql="select * from student;";try {Statement stmt=conn.createStatement();ResultSet rs=stmt.executeQuery(sql);System.out.println("学号-------------姓名---------------性别-----------年龄---------------成绩");while(rs.next()){String sno=rs.getString(1);String sname=rs.getString(2);String ssex=rs.getString(3);String sage=rs.getString(4);String sscore=rs.getString(5);System.out.println(sno+"     "+sname+"     "+ssex+"      "+sage+"      "+sscore);}} catch (SQLException e) {e.printStackTrace();System.out.println("加载驱动失败");}finally {DBtool.close(conn);}}static void delete() {                                    //删除信息@SuppressWarnings("resource")Scanner in=new Scanner(System.in);System.out.println("请输入要删除的学生信息的学号");Connection conn=DBtool.open();String sql=in.nextLine();try {Statement stmt=conn.createStatement();stmt.executeUpdate("delete from student where Sno="+sql);System.out.println("删除成功！");} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void insert() {                                      //增加信息Connection conn=DBtool.open();String sno=null;String sname=null;String ssex=null;int sage=0;String stel=null;@SuppressWarnings("resource")Scanner in=new Scanner(System.in);System.out.println("请输入添加学生的学号");sno=in.nextLine();System.out.println("请输入添加学生的姓名");sname=in.nextLine();System.out.println("请输入添加学生的性别");ssex=in.nextLine();    System.out.println("请输入添加学生的年龄");@SuppressWarnings("resource")Scanner a=new Scanner(System.in);sage=a.nextInt();	System.out.println("请输入添加学生的成绩");stel=in.nextLine();try {String sql="insert into student (Sno,Sname,Ssex,Sage,Sscore)values(?,?,?,?,?)";PreparedStatement pst=conn.prepareStatement(sql);	pst.setString(1, sno);pst.setString(2, sname);pst.setString(3,ssex);pst.setInt(4, sage);pst.setString(5, stel);@SuppressWarnings("unused")int i=pst.executeUpdate();System.out.println("添加成功");} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void query() {                                    //查询信息@SuppressWarnings("resource")Scanner in=new Scanner(System.in);System.out.println("请输入你要查询学生的学号");String sno=in.nextLine();String sql="select * from student where Sno=\""+sno+"\";";  Connection conn=DBtool.open();try {			Statement stmt=conn.createStatement();ResultSet rs=stmt.executeQuery(sql);System.out.println("学号-------------姓名---------------性别--------------年龄---------------成绩");while(rs.next()){sno=rs.getString(1);String sname=rs.getString(2);String ssex=rs.getString(3);String sage=rs.getString(4);String sscore=rs.getString(5);System.out.println(sno+"   "+sname+"      "+ssex+"      "+sage+"      "+sscore);}} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void createtable() {Connection conn=DBtool.open();String sql="create table student(Sno char(10) primary key ,Sname varchar(20),Ssex char(4),Sage int,Sscore char(11));";try {Statement stmt=conn.createStatement();stmt.execute(sql);} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void logan() {@SuppressWarnings("resource")Scanner input=new Scanner(System.in);String account;String password;do {System.out.println("请输入账号和密码，中间用空格间隔:");account=input.next();password=input.next();if(!(account.equals("admin"))) {System.out.println("账号输入错误！请重新输入账号和密码");}else if(!(password.equals("admin"))) {System.out.println("密码输入错误！请重新输入账号和密码");}}while(!(account.equals("admin")&&password.equals("admin")));System.out.println("成功登陆！！！");}static void rank() {                                    //分组排序信息Connection conn=DBtool.open();try {Statement stmt=conn.createStatement();stmt.executeUpdate("select * from student group by Ssex order by Sscore  desc;");System.out.println("排序成功！");} catch (SQLException e) {e.printStackTrace();}finally {DBtool.close(conn);}}static void fenye() {                                    //分页查询信息Connection conn=DBtool.open();String sql="select * from student limit 0,3;";try {Statement stmt=conn.createStatement();ResultSet rs=stmt.executeQuery(sql);System.out.println("学号-----姓名----------性别--------年龄--------成绩");while(rs.next()){String sno=rs.getString(1);String sname=rs.getString(2);String ssex=rs.getString(3);String sage=rs.getString(4);String sscore=rs.getString(5);System.out.println(sno+"     "+sname+"     "+ssex+"      "+sage+"      "+sscore);}} catch (SQLException e) {e.printStackTrace();System.out.println("加载驱动失败");}finally {DBtool.close(conn);}}}

案例七

package com.atguigu3.been;import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.Scanner;
import java.lang.reflect.Field;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;
import java.text.SimpleDateFormat;import org.junit.Test;import com.atguigu3.util.JDBCUtils;public class Customer {private static Scanner scanner;private static Object balance;private int id;private String name;private String email;private Date birth;public Customer() {super();}public Customer(int id,String name,String email,Date birth) {super();this.id = id;this.name = name;this.email = email;this.birth = birth;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public Date getBirth() {return birth;}public void setBirth(Date birth) {this.birth = birth;}@Overridepublic String toString() {return "Customer[id="+id+",name="+name+",email="+email+",birth="+birth+"]";}public static void main(String[] args) {// TODO Auto-generated method stubScanner in=new Scanner(System.in);System.out.println("----------用户界面---------------");System.out.println("----------1:用户登录-------------");System.out.println("----------2:用户注册-------------");System.out.println("----------3:退出------------------");System.out.println("---------------------------");int i=in.nextInt();switch(i) {case 1:login();break;case 2:register();break;case 3:balance = false;break;	default:System.out.println("输入有误!");System.exit(0);}int j;for(j=0;j<1000;j++) {menu();System.out.println("请输入所选功能的序号:");int a=in.nextInt();switch(a) {case 1:add();break;case 2:update();break;case 3:delete();break;case 4:select();break;case 5:select_1();break;case 6:select_2();break;case 7:select_3();}	}} private static void menu() {// TODO Auto-generated method stubSystem.out.println("--------------------------------------------");System.out.println("---------\t学生信息管理系统\t---------");System.out.println("---------\t1.增加学生信息\t---------");System.out.println("---------\t2.更新学生信息\t---------");System.out.println("---------\t3.删除学生信息\t---------");System.out.println("---------\t4.查询学生信息\t---------");System.out.println("---------\t5.分组查询学生信息(降序)\t---------");System.out.println("---------\t6.分组查询学生信息(升序)\t---------");System.out.println("---------\t7.分页查询学生信息\t---------");}//	//通用的增删改操作(对与数据库信息的增删查该）
//	public void update(String sql,Object ...args) {//sql中占位符的个数与可用形参的长度相同
//		Connection conn = null;
//		PreparedStatement ps = null;
//		try {
//			//1.获取数据库的连接
//			conn = JDBCUtils.getConnection();
//			//2.预编译sql语句，返回PreparedStatement的实例
//			ps = conn.prepareStatement(sql);
//			//3.填充占位符
//			for(int i = 0;i<args.length;i++)
//			{
//				ps.setObject(i+1, args[i]);//参数声明会产生错误
//			}
//			//4.执行sql语句
//			ps.execute();
//		} catch (Exception e) {
//			e.printStackTrace();
//		}finally {
//			//关闭资源
//		    JDBCUtils.closeResource(conn, ps);
//		}
//		
//		
//	}//增加数据private static void add() {// TODO Auto-generated method stubString sql="insert into customers (id,name,email,birth) values(?,?,?,?)";Connection conn = null;Scanner in = new Scanner(System.in);try {//获取数据库的连接System.out.println("------------------------------");System.out.println("请输入你要添加的学生个数:");System.out.println("------------------------------");int j=in.nextInt();for(int i = 0;i < j;i++) {System.out.println("请输入学生学号:");int id = in.nextInt();System.out.println("请输入学生姓名:");in.nextLine();String name = in.nextLine();System.out.println("请输入学生邮件:");String email = in.nextLine();System.out.println("请输入学生生日:");int birth = in.nextInt();//预编译sql语句，返回PreparedStatement的实例PreparedStatement ps =conn.prepareStatement(sql);//执行sql语句ps.setInt(1, id);ps.setString(2, name);ps.setString(3,email);ps.setInt(4, birth);int rows=ps.executeUpdate();if(rows>0) {System.out.println("添加成功!");}}}catch(Exception e) {e.printStackTrace();}}//修改数据private static void update() {// TODO Auto-generated method stubString sql = "update customers set name = ? where id = ?";Scanner in = new Scanner(System.in);Connection conn = null;try {//预编译sql语句，返回PreparedStatement的实例PreparedStatement ps = conn.prepareStatement(sql);System.out.println("---------------------------");System.out.println("请输入你想要更新的学生的学号:");int id = in.nextInt();System.out.println("请输入你想要更新的学生的姓名:");in.nextLine();String name = in.nextLine();System.out.println("请输入你想要更新的学生邮件:");String email = in.nextLine();System.out.println("请输入你想要更新的学生生日:");int birth = in.nextInt();//执行sql语句ps.setInt(1, id);ps.setString(2, name);ps.setString(3, email);ps.setInt(4, birth);ps.executeUpdate();System.out.println("更新成功!");}catch(Exception e){e.printStackTrace();System.out.println("更新失败!");}}//删除数据private static void delete() {// TODO Auto-generated method stubString sql="delete from costomers where id=?";Scanner in = new Scanner(System.in);Connection conn = null;try {//预编译sql语句，返回PreparedStatement的实例PreparedStatement ps = conn.prepareStatement(sql);System.out.println("------------------------------");System.out.println("请输入你想要删除的学生的学号:");int id = in.nextInt();//执行sql语句ps.setInt(1, id);int a = ps.executeUpdate();if(a > 0) {System.out.println("删除成功!");}}catch(Exception e) {e.printStackTrace();System.out.println("删除失败!");}}//针对于Customers表的查询操作private static void select() {// TODO Auto-generated method stubConnection conn = null;PreparedStatement ps = null;//获取结果集的元数据ResultSet rs = null;Scanner in = new Scanner(System.in);String sql = "select id,name,birth,email from customers where id = ?";try {ps = conn.prepareStatement(sql);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("请输入你想要查询的学生所对应的学号:");int id = in.nextInt();try {ps.setInt(1,id);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}try {while(rs.next()) {//获取每个列的列名String name = rs.getString("name");String email = rs.getString("email");int birth = rs.getInt("grade");System.out.println(name + " " + email + " " + birth);}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}try {rs.close();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}//分组查询学生信息(降序)private static void select_1() {// TODO Auto-generated method stubString sql="select * from costomers order by email 1111@126.com;";Connection conn = null;try {//预编译sql语句Statement a=conn.createStatement();//获取结果集的元数据ResultSet rs=a.executeQuery(sql);System.out.println("------------------------");System.out.println("数据库中的内容显示：");System.out.println("------------------------");System.out.println("学号"+"  "+"姓名"+"  "+"邮箱"+"  "+"生日");System.out.println(" ");Integer id =null;String name=null;String email=null;Integer birth=null;while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");email=rs.getString("email");birth=rs.getInt("birth");System.out.println(id+" "+name+"   "+email+"     "+birth);}rs.close();conn.close();}catch(Exception e) {e.printStackTrace();}}//分组查询学生信息(升序)private static void select_2() {// TODO Auto-generated method stubString sql="select * from costomers order by email 3333@126.com;";Connection conn = null;try {//预编译sql语句Statement a=conn.createStatement();//获取结果集的元数据ResultSet rs=a.executeQuery(sql);System.out.println("------------------------");System.out.println("数据库中的内容显示：");System.out.println("------------------------");System.out.println("学号"+"  "+"姓名"+"  "+"邮箱"+"  "+"生日");System.out.println(" ");Integer id =null;String name=null;String email=null;Integer birth=null;while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");email=rs.getString("email");birth=rs.getInt("birth");System.out.println(id+" "+name+"   "+email+"     "+birth);}rs.close();conn.close();}catch(Exception e) {e.printStackTrace();}}//分页查询学生信息private static void select_3() {// TODO Auto-generated method stubString sql="select * from costomers;";Connection conn = null;try {//预编译sql语句Statement a=conn.createStatement();//获取结果集的元数据ResultSet rs=a.executeQuery(sql);System.out.println("------------------------");System.out.println("数据库显示内容如下:");System.out.println("------------------------");System.out.println("id"+"  "+"姓名"+"  "+"邮箱"+"  "+"生日");System.out.println(" ");Integer id =null;String name=null;String email=null;Integer birth=null;while(rs.next()) {id=rs.getInt("id");name=rs.getString("name");email=rs.getString("email");birth=rs.getInt("birth");System.out.println(id+" "+name+"   "+email+"     "+birth);}rs.close();conn.close();}catch(SQLException e) {e.printStackTrace();}}public static  class User {private String user;private String password;public User() {}public User(String user, String password) {super();this.user = user;this.password = password;}private static void register() {try {Connection conn = null;try {conn = getConnection();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}Scanner in=new Scanner(System.in);System.out.println("请输入你的姓名:");String name=in.nextLine();System.out.println("请输入你的登陆密码:");String p1=in.next();System.out.println("请再次输入你的登陆密码:");String p2=in.next();if(p1.equals(p2)) {String password=p1;String sql="insert into user(name,password) values(?,?)";PreparedStatement pt = conn.prepareStatement(sql);pt.setString(1,name);pt.setString(2,password);pt.execute();System.out.println("注册成功!\n请登录:");}else {System.out.println("你输入的密码与确认密码不相同，请重新注册:");register();}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}private static void login() {try {Connection conn = null;try {conn = getConnection();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}Scanner in=new Scanner(System.in);System.out.println("请输入你的姓名:");String name=in.nextLine();System.out.println("请输入你的密码:");String password=in.next();String sql = "select name,password from user where name=? and password=?";PreparedStatement pt = conn.prepareStatement(sql);pt.setString(1, name);pt.setString(2, password);ResultSet rs = pt.executeQuery();//从给出的账号密码来检测是否有相同的账号密码if(rs.next()) {System.out.println("登陆成功!");}else {System.out.println("姓名或密码错误!\n请重新登陆:");login();}} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}@Overridepublic String toString() {return "User [user=" + user + ", password=" + password + "]";}public String getUser() {return user;}public void setUser(String user) {this.user = user;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}//连接数据库public static Connection getConnection() throws Exception{//读取配置文件中的四个基本信息InputStream is = Connection.class.getClassLoader().getResourceAsStream("jdbc.properties");Properties pros = new Properties();pros.load(is);String user = pros.getProperty("user");String password = pros.getProperty("password");String url = pros.getProperty("url");String diverClass = pros.getProperty("diverClass");//加载驱动Class.forName(diverClass);//获取连接Connection conn = DriverManager.getConnection(url,user,password);System.out.println(conn);return conn;}//关闭连接和Statement的操作public static void closeResource(Connection conn,Statement ps) {try {if(ps != null)ps.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(conn != null)conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}//关闭资源的操作public static void closeResource(Connection conn,Statement ps,ResultSet rs) {try {if(ps != null)ps.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(conn != null)conn.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(rs != null)rs.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}public static class update {public static int update(String sql, Object... args) {// 动态参数或者是可变参数的意思。Connection con = null;PreparedStatement pr = null;try {con = getConnection();pr = con.prepareStatement(sql);for (int i = 1; i <= args.length; i++) {pr.setObject(i, args[i - 1]);}/** pr.execute(); 如果执行的是查询操作，有返回结果则返回ture 如果执行的是增删改，没有返回结果的，此方法返回false*/// pr.execute();return pr.executeUpdate();// 执行了则返回影响的行数，失败则返回0，返回值为int类型} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {closeResource(con, pr);}return 0;}public <T> T find1(Class<T> clazz,String sql,Object ...args) {Connection con = null;PreparedStatement pr=null;ResultSet re=null;try {//获取连接con = getConnection();            //预编译处理sql语句pr = con.prepareStatement(sql);//填充占位符for(int i=1;i<=args.length;i++) {pr.setObject(i, args[i-1]);}//接受结果re = pr.executeQuery();//获取结果集的元数据ResultSetMetaData rsmd = re.getMetaData();//通过元数据获取结果集的列数int count = rsmd.getColumnCount();if(re.next()) {T t = clazz.newInstance();for(int i=0;i<count;i++) {//获取每一列的值Object value = re.getObject(i+1);//获取每个列的列名String columnName = rsmd.getColumnName(i+1);//给t对象指定的某个属性值，依次赋值为value//得到属性Field field = clazz.getDeclaredField(columnName);//保证可以访问，防止是私有属性不可以访问field.setAccessible(true);field.set(t, value);}return t;}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {closeResource(con, pr, re);}return null;}public <T> List<T> find2(Class<T> clazz,String sql,Object ...args){Connection con = null;PreparedStatement pr=null;ResultSet re=null;try {//获取连接con = getConnection();            //预编译处理sql语句pr = con.prepareStatement(sql);//填充占位符for(int i=1;i<=args.length;i++) {pr.setObject(i, args[i-1]);}//接受结果re = pr.executeQuery();//获取结果集的元数据ResultSetMetaData rsmd = re.getMetaData();//通过元数据获取结果集的列数int count = rsmd.getColumnCount();//创建集合ArrayList<T> list = new ArrayList<T>();while(re.next()) {//if改为whileT t = clazz.newInstance();//空的构造器for(int i=0;i<count;i++) {//获取每一列的值Object value = re.getObject(i+1);//获取每个列的列名String columnName = rsmd.getColumnName(i+1);//给t对象指定的某个属性值，依次赋值为value//得到属性Field field = clazz.getDeclaredField(columnName);//保证可以访问，防止是私有属性不可以访问field.setAccessible(true);field.set(t, value);}list.add(t);//将对象添加到数组中}return list;} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}finally {closeResource(con, pr, re);}return null;}}
}

案例八

JDBCUtil.java

package demo;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class JDBCUtil {private static final String connectionurl="jdbc:mysql://localhost:3306/web01?serverTimezone=GMT";private static final String username="root";private static final String password="0721";public static Connection getConnection() {try {Class.forName("com.mysql.cj.jdbc.Driver");return DriverManager.getConnection(connectionurl, username, password);	} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}return null;}public static void close(ResultSet rs,Statement stmt,Connection con) {try {if(rs!=null)rs.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(stmt!=null)stmt.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}try {if(con!=null)con.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}
}

demo_main.java

package demo;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;public class demo_main {public static void denglu(String id,String mima) {try {Class.forName("com.mysql.cj.jdbc.Driver");String url="jdbc:mysql://localhost:3306/web01?serverTimezone=GMT";String user="root";String password="0721";Connection con=DriverManager.getConnection(url, user, password);	Statement stmt=con.createStatement();String sql="select *from guanliyuan where id= '"+id+"' and mima='"+mima+"'";ResultSet rs = stmt.executeQuery(sql);if(rs.next()) {System.out.println("登陆成功");}else {System.out.println("未查询到该用户，请选择是否注册：1.是   2.否");Scanner w=new Scanner(System.in);int choice=w.nextInt();switch(choice) {case 1:System.out.println("请输入添加的管理员账号、密码：");String sid=w.next();String smima=w.next();add2(sid,smima);break;case 2:System.out.println("欢迎下次使用！");	System.exit(0);}	}} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}public static void add2(String id,String mima) {Connection cos=null;PreparedStatement stm=null;ResultSet rc=null;try {Class.forName("com.mysql.cj.jdbc.Driver");String url="jdbc:mysql://localhost:3306/web01?serverTimezone=GMT";String user="root";String password="0721";cos=DriverManager.getConnection(url, user, password);	String sql="insert into guanliyuan(id,mima) value(?,?)"; stm=cos.prepareStatement(sql);stm.setString(1, id);stm.setString(2, mima);int result=stm.executeUpdate();if(result>0) {System.out.println("注册成功");menu();}else {System.out.println("注册失败");System.exit(0);}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}  finally {if(cos!=null)try {cos.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}if(stm!=null)try {stm.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}if(rc!=null)try {rc.close();} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}public static void menu() {System.out.println("        =========欢迎使用用户信息管理系统========="+"\n");Scanner s = new Scanner(System.in);System.out.println("请先登录或注册：1.登录  2.注册");int cho=s.nextInt();switch(cho) {case 1:System.out.println("请输入管理员账号");String id=s.next();System.out.println("请输入密码");String mima=s.next();denglu(id,mima);break;case 2:System.out.println("请输入添加的管理员账号、密码：");String sid=s.next();String smima=s.next();add2(sid,smima);break;}System.out.println("1.添加用户   2.删除用户   3.查询    4.修改密码    5.展示所有信息    6.按密码排序    7.分页查询    8.退出 ");int num = s.nextInt();switch(num) {case 1:System.out.println("请输入添加的用户姓名、密码：");String user = s.next();String pass=s.next();add(user,pass);break;case 2:System.out.println("请输入要删除的用户ID：");int idss=s.nextInt();delete(idss);break;case 3:System.out.println("请输入查询的用户姓名、密码：");String cname=s.next();String cpassword=s.next();find(cname,cpassword);break;case 4:System.out.println("请输入要修改密码用户的ID和新密码：");int ids=s.nextInt();String newpass=s.next();change(ids,newpass);break;case 5:all();break;case 6:paixu();break;case 7:System.out.println("请输入要查询第几页以及每页数据条数：");int number=s.nextInt();int count=s.nextInt();page(number,count);break;case 8:System.out.println("谢谢您的使用");System.exit(0);}}public static void main(String[] args) {menu();}public static void all() {Connection con=null;ResultSet rs=null;Statement stmt=null;try {con=JDBC.getConnection();stmt=con.createStatement();rs= stmt.executeQuery("select * from user");while(rs.next()) {System.out.println(rs.getInt("ID")+" "+rs.getString("username")+" "+rs.getString("password"));}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {JDBC.close(rs, stmt, con);}}public static boolean find(String username,String password) {Connection con=null;Statement stmt=null;ResultSet rs=null;try {con=JDBC.getConnection();stmt=con.createStatement();String sql="select *from user where username= '"+username+"' and password='"+password+"'";rs=stmt.executeQuery(sql);if(rs.next()) {System.out.println(rs.getInt("ID")+" "+rs.getString("username")+" "+rs.getString("password"));return true;}else {System.out.println("未查询到该用户");return false;}}catch(Exception e) {e.printStackTrace();}finally {JDBC.close(rs, stmt, con);}return false;}	//分页查询public static void page(int pagenumber,int pagecount) {Connection con=null;ResultSet rs=null;PreparedStatement stmt=null;try {Class.forName("com.mysql.cj.jdbc.Driver");String url="jdbc:mysql://localhost:3306/web01?serverTimezone=GMT";String user="root";String password="0721";con=DriverManager.getConnection(url, user, password);stmt=con.prepareStatement("select * from user limit ?,?");stmt.setInt(1,(pagenumber-1)*pagecount);	stmt.setInt(2, pagecount);rs=stmt.executeQuery();while(rs.next()) {System.out.println(rs.getInt("ID")+" "+rs.getString("username")+" "+rs.getString("password"));}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {JDBC.close(rs, stmt, con);}}
//添加public static void add(String username,String password) {Connection con=null;ResultSet rs=null;PreparedStatement stmt=null;try {con=JDBC.getConnection();String sql="insert into user(username,password) value(?,?)";stmt=con.prepareStatement(sql);stmt.setString(1, username);stmt.setString(2, password);int result=stmt.executeUpdate();if(result>0) {System.out.println("添加成功");}else {System.out.println("添加失败");}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {    JDBC.close(rs, stmt, con);}}//删除 public static void delete(int id) {Connection con=null;ResultSet rs=null;PreparedStatement stmt=null;try {con=JDBC.getConnection();String sql="delete from user where id=?";stmt=con.prepareStatement(sql);stmt.setInt(1, id);int result=stmt.executeUpdate();if(result>0) {System.out.println("删除成功");}else {System.out.println("删除失败");}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {    JDBC.close(rs, stmt, con);}}
//修改public static void change(int id,String newpassword) {Connection con=null;ResultSet rs=null;PreparedStatement stmt=null;try {con=JDBC.getConnection();String sql="update user set password=? where id=?";stmt=con.prepareStatement(sql);stmt.setString(1, newpassword);stmt.setInt(2, id);int result=stmt.executeUpdate();if(result>0) {System.out.println("修改成功");}else {System.out.println("修改失败");}}  catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {    JDBC.close(rs, stmt, con);}}public static void paixu() {Connection con=null;ResultSet rs=null;Statement stmt=null;try {con=JDBC.getConnection();stmt=con.createStatement();rs= stmt.executeQuery("SELECT * from user ORDER BY password ASC");while(rs.next()) {System.out.println(rs.getInt("ID")+" "+rs.getString("username")+" "+rs.getString("password"));}}catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {JDBC.close(rs, stmt, con);}}}