Mybatis及JDBC执行SQL区别对比

1、JDBC方式

package com.kdy.tests;

import com.kdy.pojo.Emp;
import org.junit.Test;

import java.sql.*;

public class JDBCTest {
    @Test
    public void jbjc() throws ClassNotFoundException, SQLException {
        //1、注册驱动
        Class  aClass1 = Class.forName("com.mysql.cj.jdbc.Driver");
        //2、创建数据库链接 DriverManager.getConnect() 方法 获取数据库链接
        String url = "jdbc:mysql://localhost:3306/mybatis";
        String username = "root";
        String password = "root";
        //3、获取链接
        Connection connection = DriverManager.getConnection(url, username, password);
        //SQL语句
        String sql = "SELECT  *  from EMP where id=?";

        //4、使用PreparedStatement 解析SQL
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setInt(1,1);
        ResultSet resultSet = preparedStatement.executeQuery();
        if(resultSet.next()){
            Emp emp = new Emp();
            emp.setId(resultSet.getInt("id"));
            emp.setUsername(resultSet.getString("username"));
            System.out.println(emp);
        }


    }
}

2、Mybatis方式

package com.kdy.tests;

import com.kdy.mapper.EmpMapper;
import com.kdy.pojo.Emp;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;

public class MybatisTest {
    SqlSession sqlSession;
    @Test
    public void test01() throws IOException {
        //根据XML构建成sqlSessionFactory
        String config = "mybatis.config.xml";
        //将XML构建成输入流
        InputStream inputStream= Resources.getResourceAsStream(config);
        //建成sqlSessionFactory
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        /*
        *
        * 可以设置事务为自动提交 ,因为执行 增删改的时候需要手动提交事务
        * SqlSession openSession(boolean autoCommit);
           
          SqlSession openSession(Connection connection);

          SqlSession openSession(TransactionIsolationLevel level);

          SqlSession openSession(ExecutorType execType);

          SqlSession openSession(ExecutorType execType, boolean autoCommit);

          SqlSession openSession(ExecutorType execType, TransactionIsolationLevel level);

          SqlSession openSession(ExecutorType execType, Connection connection);
        *
        *
        *
        *
        * */


        sqlSession = sessionFactory.openSession();

        Object o = sqlSession.selectOne("com.kdy.mapper.EmpMapper.selectEmp", 1);

        System.out.println(o);
        //Mybatis 在getMapper时就会给创建JDK动态代理
        EmpMapper mapper = sqlSession.getMapper(EmpMapper.class);
        System.out.println(mapper.getClass());
        System.out.println(mapper);
        Emp emp = mapper.selectEmp(1);

        System.out.println(emp);

    }
}