jdbc（java连接数据库）

/*

1加载驱动
2连接数据库
3向数据库发送sql的对象Statement : CRUD
4编写sql
5执行查询sql ，返回一个resultSet : 结果集
6关闭连接，释放资源(一定要做)先开后关

*/
/*
首先添加数据库依赖
<!--mysql的驱动-->
<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.22</version>
</dependency>
*/

package jdbc;

import java.sql.*;

public class Test {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //配置信息
        //useUnicode=true&characterEncoding=utf-8 解决中文乱码
        String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8&serverTimezone=PRC";
        String username = "root";
        String password = "";

        //加载驱动
        Class.forName("com.mysql.cj.jdbc.Driver");
        //连接数据库
        Connection connection = DriverManager.getConnection(url,username,password);
        //向数据库发送sql的对象Statement : CRUD
        Statement statement = connection.createStatement();
        //编写sql
        String sql = "select * from users";
        //执行查询sql ，返回一个resultSet : 结果集
        ResultSet rs = statement.executeQuery(sql);
        while (rs.next()){
            System.out.println("id="+rs.getObject("id"));
            System.out.println("name="+rs.getObject("name"));
            System.out.println("password="+rs.getObject("password"));
            System.out.println("email="+rs.getObject("email"));
            System.out.println("birthday="+rs.getObject("birthday"));
        }
        //关闭连接，释放资源(一定要做)先开后关
        rs.close();
        statement.close();
        connection.close();
    }
}