项目目录结构
数据库配置
1.创建goods表
2.创建goods实体
package homework.MyJDBC;public class Goods {private int id;private String gId;private String gName;private float gPrice;private int gNum;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getgId() {return gId;}public void setgId(String gId) {this.gId = gId;}public String getgName() {return gName;}public void setgName(String gName) {this.gName = gName;}public float getgPrice() {return gPrice;}public void setgPrice(float gPrice) {this.gPrice = gPrice;}public int getgNum() {return gNum;}public void setgNum(int gNum) {this.gNum = gNum;}@Overridepublic String toString() {return "Goods{" +"id=" + id +", gId='" + gId + '\'' +", gName='" + gName + '\'' +", gPrice=" + gPrice +", gNum=" + gNum +'}';}
}
3.创建接口GoodsDao
package homework.MyJDBC;import java.sql.SQLException;
import java.util.List;public interface GoodsDao {//增加public abstract void addGoods(Goods goods);//删除public abstract void delGoods(int id);//修改public abstract void updateGoods(Goods goods);//查询所有public abstract List<Goods> selectAllGoods() throws SQLException;//按照id查询public abstract List<Goods> selectGoodsById(int id) throws SQLException;
}
4.创建实现类工具包 MyJDBCUtil
package homework.MyJDBC;import com.mysql.jdbc.Connection;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;public class MyJDBCUtil {private static Properties properties = new Properties();static {//1.注册驱动 告诉jdbc我们使用哪一个数据库厂商的驱动try {//1.1 读取文件中的信息FileInputStream in = null;try {in = new FileInputStream("src/homework/MyJDBC/resource/properties");} catch (FileNotFoundException e) {throw new RuntimeException(e);}// 1.2 Properties对象中有一个load方法properties.load(in); //将文件相关的信息加载到properties 对象中Class.forName(properties.getProperty("driverClassName"));} catch (ClassNotFoundException e) {throw new RuntimeException(e);} catch (IOException e) {throw new RuntimeException(e);}}public static Connection GetConnection() {//2.通过驱动管理器获取一个链接Connection connection = null;try {connection = (Connection) DriverManager.getConnection(properties.getProperty("url"),properties.getProperty("username"), properties.getProperty("password"));} catch (SQLException throwables) {throwables.printStackTrace();}return connection;}public static void release(Connection conn, Statement sm , ResultSet rs){if(rs!=null){try {rs.close();} catch (SQLException e) {e.printStackTrace();}rs =null; //让jvm来回收它}if(sm!=null){try {sm.close();} catch (SQLException e) {e.printStackTrace();}sm =null; //让jvm来回收它}if(conn!=null){try {conn.close();} catch (SQLException e) {e.printStackTrace();}conn =null; //让jvm来回收它}}}
5.创建实现类 ImplGoods
package homework.MyJDBC;import java.sql.*;
import java.util.ArrayList;
import java.util.List;public class ImplGoods implements GoodsDao {@Overridepublic void addGoods(Goods goods) {//获取connConnection conn = MyJDBCUtil.GetConnection();Statement st = null;String sql = "INSERT INTO goods VALUES (NULL,'"+goods.getgId()+"','"+goods.getgName()+"',"+goods.getgPrice()+","+goods.getgNum()+")";System.out.println(sql);try {st = conn.createStatement();int result = st.executeUpdate(sql);if (result>0){System.out.println("添加成功!");}else {System.out.println("添加失败！");}} catch (SQLException throwables) {throwables.printStackTrace();}finally {try {conn.close();} catch (SQLException throwables) {throwables.printStackTrace();}try {st.close();} catch (SQLException throwables) {throwables.printStackTrace();}}}@Overridepublic void delGoods(int id) {//获取connConnection conn = MyJDBCUtil.GetConnection();Statement st = null;String sql = "DELETE FROM goods WHERE id="+id;System.out.println(sql);try {st = conn.createStatement();int result = st.executeUpdate(sql);if (result>0){System.out.println(id+"商品删除成功!");}else {System.out.println(id+"商品删除失败！");}} catch (SQLException throwables) {throwables.printStackTrace();}finally {try {conn.close();} catch (SQLException throwables) {throwables.printStackTrace();}try {st.close();} catch (SQLException throwables) {throwables.printStackTrace();}}}@Overridepublic void updateGoods(Goods goods) {//获取connConnection conn = MyJDBCUtil.GetConnection();Statement st = null;String sql = "UPDATE goods SET g_id ='"+ goods.getgId()+"',g_name='"+goods.getgName()+"',g_price="+goods.getgPrice()+",g_num="+goods.getgNum()+ " WHERE id ="+goods.getId();System.out.println(sql);try {st = conn.createStatement();int result = st.executeUpdate(sql);if (result>0){System.out.println("修改成功!");}else {System.out.println("修改失败！");}} catch (SQLException throwables) {throwables.printStackTrace();}finally {try {conn.close();} catch (SQLException throwables) {throwables.printStackTrace();}try {st.close();} catch (SQLException throwables) {throwables.printStackTrace();}}}@Overridepublic List<Goods> selectAllGoods() throws SQLException {com.mysql.jdbc.Connection connection = MyJDBCUtil.GetConnection();//3.创建向数据库发送sql的statement对象Statement st = connection.createStatement();//4.发送sql后获得一个封装了查询结果的ResultSet对象ResultSet rs = st.executeQuery("select * from goods");List<Goods> list = new ArrayList<Goods>();while(rs.next()){Goods goods = new Goods();goods.setId(rs.getInt("id"));goods.setgId(rs.getString("g_id"));goods.setgName(rs.getString("g_name"));goods.setgPrice(rs.getInt("g_price"));goods.setgNum(rs.getInt("g_num"));list.add(goods);}//释放资源MyJDBCUtil.release(connection,st,rs);return list;}@Overridepublic List<Goods> selectGoodsById(int id) throws SQLException {com.mysql.jdbc.Connection connection = MyJDBCUtil.GetConnection();//3.创建向数据库发送sql的statement对象Statement st = connection.createStatement();//4.发送sql后获得一个封装了查询结果的ResultSet对象ResultSet rs = st.executeQuery("select * from goods where id="+id);List list = new ArrayList();while(rs.next()){Goods goods = new Goods();goods.setId(rs.getInt("id"));goods.setgId(rs.getString("g_id"));goods.setgName(rs.getString("g_name"));goods.setgPrice(rs.getInt("g_price"));goods.setgNum(rs.getInt("g_num"));list.add(goods);}//释放资源MyJDBCUtil.release(connection,st,rs);return list;}
}
6.创建测试类 test
package homework.MyJDBC;import java.sql.SQLException;public class test {public static void main(String[] args) throws SQLException {Goods goods = new Goods();goods.setId(1);goods.setgId("001");goods.setgName("qwe");goods.setgPrice(1);goods.setgNum(1);ImplGoods implGoods = new ImplGoods();
// implGoods.addGoods(goods);implGoods.delGoods(6);// implGoods.updateGoods(goods);
// System.out.println(implGoods.selectAllGoods());System.out.println(implGoods.selectGoodsById(1));}
}
