jdbc连接数据库的三种方法

1. 注意：对于第一种方法，使用Properties时，在setProperty时，用户和密码必须是user和password ，否则则会报错。

`public class Demo01 {
    @Test  //获取连接方式一
    public void testConn01() throws Exception {
        //前面是jdk提供的接口 ，后面是 mysql提供的 实现类
        Driver driver = new com.mysql.jdbc.Driver();
        String url = "jdbc:mysql://10.8.159.36:3306/day04";
        Properties info =new Properties();
        info.setProperty("user", "root");
        info.setProperty("password", "123456");

        Connection conn = driver.connect(url, info);
        System.out.println(conn);

    }
    @Test//连接方式二
    public void testConn02() throws SQLException {
        Driver driver = new com.mysql.jdbc.Driver();
        String url = "jdbc:mysql://10.8.159.36:3306/day04";
        String user = "root";
        String password = "123456";
        //注册驱动
        DriverManager.registerDriver(driver);
        Connection conn = DriverManager.getConnection(url, user, password);
        System.out.println("2");
        System.out.println(conn);
    }


    @Test//连接方式三
    public void testConn03() throws Exception {

        String url = "jdbc:mysql://10.8.159.36:3306/day04";
        String user = "root";
        String password = "123456";
        //注册驱动
        Class.forName("com.mysql.jdbc.Driver");

        Connection conn = DriverManager.getConnection(url, user, password);
        System.out.println("3");
        System.out.println(conn);
    }
}`