怎样用java连接mysql

import java.sql.*;

public class MySQLDemo{
    static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/useing?useSSL=false&serverTimezone=UTC";
    static final String USER = "root";
    static final String PASS = "admin";

    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try {
            //注册驱动
            Class.forName(JDBC_DRIVER);
            //打开连接
            System.out.println("连接数据库");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
            //执行查询
            System.out.println("实例化Statement对象");
            stmt = conn.createStatement();
            String sql ;
            sql = "select * from user";

            ResultSet rs = stmt.executeQuery(sql);
            //展开结果集数据库
            while(rs.next()){
                //通过字段检索
                int id = rs.getInt("id");
                String name = rs.getString("name");
                String age = rs.getString("age");
                //输出数据
                System.out.print("ID：" + id);
                System.out.print(",NAME：" + name);
                System.out.print(",AGE：" + age);
                System.out.print("\n");
            }
            //完成后关闭
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException se) {
            //处理JDBC错误
            se.printStackTrace();
        }catch(Exception e){
            //处理Class.forName错误
            e.printStackTrace();
        }finally {
            //关闭资源
            try {
                if (stmt != null) stmt.close();
            } catch (SQLException se) {
                //啥都不干
                se.printStackTrace();
            }
            try{
                if(conn != null) conn.close();
            }catch (SQLException se){
                se.printStackTrace();
            }
        }
        System.out.println("这里是finally的结束");
    }
}