jdbc连接mysql进行增加数据，更新数据，删除数据

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.PseudoColumnUsage;
import java.sql.SQLException;
import java.util.Properties;
import org.junit.Test;
import com.mysql.cj.jdbc.Driver;
import com.mysql.cj.x.protobuf.MysqlxPrepare.Prepare;
public class connection {
    public static Connection getuser () 
    {
      Connection conn = null;
      try {
        Driver driver=new Driver();//加载驱动
        String use="jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC";
        /*
         * 3306:端口号
         * test:连接数据库
         */
        Properties infoProperties=new Properties();
        infoProperties.setProperty("user","root");
        /*用户名称*/
        infoProperties.setProperty("password","root");
        /* 用户密码*/
        conn = driver.connect(use, infoProperties);
      } catch (SQLException e) {
        e.printStackTrace();
      }
      return conn;
    }
    @Test
    public void test01()
    {
        Connection conn=getuser();
        System.out.println(conn);
    }
    @Test
    public void test02() //插入数据
    {
      Connection conn=getuser();
      String sql=" INSERT INTO customers(id,`name`,email) value(?,?,?)"; //占位符处理
      PreparedStatement ps = null;
      try {
        //预编译
        ps = conn.prepareStatement(sql);
        ps.setInt(1, 22);
        ps.setString(2,"李太白");
        ps.setString(3,"2860467163.@qqcom");
        ps.execute();
      } catch (SQLException e) {
        e.printStackTrace();
      }
      try {//关闭连接
        ps.close();
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    @Test
    public void test03()
    {
      Connection conn=getuser();
      String sql="update customers set email=? where id=?";
      PreparedStatement ps = null;
      try {
        ps = conn.prepareStatement(sql);
        ps.setString(1,"2860467163.@qqcom");
        ps.setInt(2, 1);
        ps.execute();
      } catch (SQLException e) {
        e.printStackTrace();
      }
      try {
        ps.close();
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
    @Test
    public void test04()
    {
      Connection conn=getuser();
      String sql=" DELETE FROM customers WHERE id =?";
      PreparedStatement ps = null;
      try {
        ps = conn.prepareStatement(sql);
        ps.setInt(1, 22);
        ps.execute();
      } catch (SQLException e) {
        e.printStackTrace();
      }
      try {
        ps.close();
        conn.close();
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
}