是什么？

1、理解

1、就是帮助我们连接和管理数据库

怎么用？

1、步骤

1、注册驱动
2、获取连接
3、编写sql语句
4、关闭数据库

2、简单的例子

1、例子1 （普通连接）

package com.qtedu.jdbc;
import com.mysql.jdbc.*;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * 这是第一个jdbc程序，完成简单的操作
 */
public class Jdbc01 {
    public static void main(String[] args) throws SQLException {

//    前置工作，安装connector驱动
    //1.注册驱动
        Driver driver = new Driver();

        //2.得到连接
        String url = "jdbc:mysql://localhost:3306/qt_db02";
        Properties properties = new Properties();
        properties.setProperty("user","root");//用户
        properties.setProperty("password","123456") ;
        Connection connect =  driver.connect(url,properties);
        //    3.执行sql语句
        String sql = "insert into actor values(null,'缺氧','0', '1970-10-10' ,'110')";
        //发送sql语句执行
        Statement statement = connect.createStatement();
        int rowupdate = statement.executeUpdate(sql);//如果是dml语句rowupdate是返回的函数

        System.out.println(rowupdate> 0? "成功":"失败");
        //    4.关闭资源连接
        statement.close();
        connect.close();

    }
}

2、例子2用反射

    //方法二   动态加载，更加灵活
    @Test
    public void connect02() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
        Class aclass  = Class.forName("com.mysql.jdbc.Driver");
        Driver driver =  (Driver) aclass.newInstance();
        String url  = "jdbc:mysql://localhost:3306/qt_db02";
        Properties properties = new Properties();
        properties.setProperty("user","root");
        properties.setProperty("password","123456");
        Connection connection = driver.connect(url,properties);
        System.out.println("方式二："+connection);
    }

3、方法3使用DriverManager 替代 Driver 进行统一管理

public void connect03() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
    //反射加载Driver
    Class aclass = Class.forName("com.mysql.jdbc.Driver");
    Driver driver = (Driver) aclass.newInstance();
    //创建url 和user 和password
    String url = "jdbc:mysql://localhost:3306/qt_db02";
    String user = "root";
    String password = "123456";

    DriverManager.registerDriver(driver);//注册驱动

    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，简化代码

    public void connect04() throws ClassNotFoundException, SQLException {
        //加载Driver 类时，会自动完成驱动注册（Driver底层代码中有一个static代码块编写了DriverManager.registerDriver( new driver);方法
        Class aclass = Class.forName("com.mysql.jdbc.Driver");

        //创建url和user和password
        String url = "jdbc:mysql://localhost:3306/qt_db02";
        String user = "root";
        String password = "123456";

        Connection connection = DriverManager.getConnection(url,user,password);
        System.out.println("第四种连接方式"+connection);
    }