Jdbc连接mysql的五种连接方式

一：五种连接方式直接上码

package com.wyjedu.jdbc;import com.mysql.jdbc.Driver;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;/*** 测试连接方式*/public class Demo_jdbc02 {public static void main(String[] args) throws SQLException, ClassNotFoundException, InstantiationException, IllegalAccessException, IOException {//测试连接方式一：connect01();//测试连接方式二：connect02();//测试连接方式三：connect03();//测试连接方式四：connect04();//测试连接方式五connect05();}//1.第一种连接方式 直接创建driver 对象public static void connect01() throws SQLException {//(1):注册驱动：Driver driver = new Driver();//(2):得到连接String url = "jdbc:mysql://localhost:3306/my_jdbc";Properties properties = new Properties();//获取用户 密码properties.setProperty("user","root");properties.setProperty("password","wyj");//开始连接Connection connect = driver.connect(url, properties);System.out.println("连接方式一 = " + connect);connect.close();}// 第二种连接方式 通过反射来连接public static void connect02() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {//(1):注册驱动//反射加载Driver类，创建它的Class对象，动态加载，更加灵活，减少依赖性Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");// 实例化aclass的一个对象Driver driver = (Driver) aClass.newInstance();//(2):得到连接String url = "jdbc:mysql://localhost:3306/my_jdbc";Properties properties = new Properties();properties.setProperty("user","root");properties.setProperty("password","wyj");Connection connect = driver.connect(url, properties);System.out.println("方式二 = " + connect);connect.close();}//第三种连接方式 使用DriverManger  替代 driver  进行统一管理public static void connect03() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {//(1):注册驱动Class<?> aClass = Class.forName("com.mysql.jdbc.Driver");Driver driver = (Driver) aClass.newInstance();//注册驱动 driverDriverManager.registerDriver(driver);//(2):得到连接String url = "jdbc:mysql://localhost:3306/my_jdbc";//可以 不用创建 propertyString user = "root";String password = "wyj";Connection connection = DriverManager.getConnection(url, user, password);System.out.println("第三种连接方式 = " + connection);}//4.使用 Class.forName 自动完成注册驱动，（其driver 源码当中有解释）public static void connect04() throws ClassNotFoundException, SQLException {//(1):注册驱动Class.forName("com.mysql.jdbc.Driver");/*** Driver* 源码：static {*         try {*             注意这里是和方式三当中我们写的是一样的，也就是自动完成注册*             DriverManager.registerDriver(new Driver());*         } catch (SQLException var1) {*             throw new RuntimeException("Can't register driver!");*         }*     }**///(2):得到连接String url = "jdbc:mysql://localhost:3306/my_jdbc";String user = "root";String password = "wyj";Connection connection = DriverManager.getConnection(url, user, password);System.out.println("第四种连接方式 = " + connection);connection.close();}//5.DriverManager getConnection ("jdbc: mysql: //localhost: 3306/testdb","root//"root");中的字符串各个值,比如端口,数据库,用户名,密码为了方便,我们可以将信息//写入到 properties文件中,方便操作//这样在连接不同的数据库时，可以直接修改配置文件，而不用修改源码public static void connect05() throws IOException, ClassNotFoundException, SQLException {//通过Properties获取配置文件的信息Properties properties = new Properties();properties.load(new FileInputStream("src//mysql.properitys"));//获取配置文件的相关信息String user = properties.getProperty("user");String password = properties.getProperty("password");String driver = properties.getProperty("driver");String url = properties.getProperty("url");//(1):注册驱动(可以不用写  在导入的jar包下  有相关的配置文件信息 会自动加载，但你一般还是会写上 这样可以清楚知道，注册是谁的数据库)Class.forName(driver);Connection connection = DriverManager.getConnection(url, user, password);System.out.println("连接方式五 = "+connection);connection.close();}}