jdbc:几种方式连接数据库

package com.lwb.connection;

import org.junit.jupiter.api.Test;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

public class ConnectionTest {

    @Test
    public void testConnection1() throws SQLException {

        Driver driver = new com.mysql.jdbc.Driver();

        String url="jdbc:mysql://localhost:3306/test";

        Properties info=new Properties();
        info.setProperty("user","root");
        info.setProperty("password","1234");

        Connection conn =driver.connect(url,info);
        System.out.println("test1:  "+conn);
    }


//    对方式一的迭代：在如下的程序中不会出现第三方的api，使得程序具有更好的可移植性。
    @Test
    public void testConnextion2() throws Exception {
//        1、获取java实现类对象，使用反射
        Class clazz =Class.forName("com.mysql.jdbc.Driver");
        Driver driver=(Driver) clazz.newInstance();
//      2、提供要连接的数据库
        String url="jdbc:mysql://localhost:3306/test";
//      3、提供连接需要的用户名和密码
        Properties info=new Properties();
        info.setProperty("user","root");
        info.setProperty("password","1234");
//        4、获取连接
        Connection conn=driver.connect(url,info);
        System.out.println("test2:  "+conn);

    }
//    方式三：使用DriverManger替换Driver
    @Test
    public void testConnection3() throws Exception{
//        1、获取Driver实现类的对象
        Class clazz=Class.forName("com.mysql.jdbc.Driver");
        Driver driver=(Driver) clazz.newInstance();

//        2、提供账号密码和url
        String url="jdbc:mysql://localhost:3306/test";
        String user="root";
        String password="1234";
//        3、注册驱动
        DriverManager.registerDriver(driver);
//        4、获取连接
        Connection conn=DriverManager.getConnection(url,user,password);
        System.out.println("test3:  "+conn);
    }
    //方式四：可以只加载驱动，不用显示的注册驱动了。
    @Test
    public void testConnection4() throws Exception {
        String url="jdbc:mysql://localhost:3306/test";
        String user="root";
        String password="1234";

        //加载driver
        Class.forName("com.mysql.jdbc.Driver");

        Connection conn=DriverManager.getConnection(url,user,password);
        System.out.println("test4:  "+conn);

    }
    //方式5：用配置文件获取参数
    @Test
    public void testConnection5() throws Exception{
        InputStream is=ConnectionTest.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 driverClass=pros.getProperty("driverClass");
        //加载驱动
        Class.forName(driverClass);

        //获取连接
        Connection conn=DriverManager.getConnection(url,user,password);
        System.out.println("test5:  "+conn);
    }

}

jdbc.properties文件：

user=root
password=1234
url=jdbc:mysql://localhost:3306/test
driverClass=com.mysql.jdbc.Driver