MyBatis学习笔记二——CRUD操作

一、使用MyBatis对表执行CRUD操作——基于XML的实现

1. 定义sql映射xml文件

<mapper namespace="me.lizhenhua.mapping.userMapper">
    
    
    <select id="getUser" parameterType="int" 
        resultType="me.lizhenhua.domain.User">
        select * from users where id=#{id}
    select>

    
    <insert id="addUser" parameterType="me.lizhenhua.domain.User">
        insert into users(name,age) values(#{name},#{age})
    insert>

    
    <delete id="deleteUser" parameterType="int">
        delete from users where id=#{id}
    delete>

    
    <update id="updateUser" parameterType="me.lizhenhua.domain.User">
        update users set name=#{name},age=#{age} where id=#{id}
    update>

    
    <select id="getAllUsers" resultType="me.lizhenhua.domain.User">
        select * from users
    select>

mapper>

1. 单元测试类代码

package me.lizhenhua.test;

import java.util.List;
import me.lizhenhua.domain.User;
import me.lizhenhua.mapping.UserMapperI;
import me.lizhenhua.util.MyBatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

public class TestCRUDByAnnotationMapper {

    @Test
    public void testAdd(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        User user = new User();
        user.setName("用户xdp");
        user.setAge(20);
        int add = mapper.add(user);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(add);
    }

    @Test
    public void testUpdate(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        User user = new User();
        user.setId(3);
        user.setName("孤傲苍狼_xdp");
        user.setAge(26);
        //执行修改操作
        int retResult = mapper.update(user);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testDelete(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //执行删除操作
        int retResult = mapper.deleteById(7);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(retResult);
    }

    @Test
    public void testGetUser(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //执行查询操作，将查询结果自动封装成User返回
        User user = mapper.getById(8);
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(user);
    }

    @Test
    public void testGetAll(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession();
        //得到UserMapperI接口的实现类对象，UserMapperI接口的实现类对象由sqlSession.getMapper(UserMapperI.class)动态构建出来
        UserMapperI mapper = sqlSession.getMapper(UserMapperI.class);
        //执行查询操作，将查询结果自动封装成List返回
        List lstUsers = mapper.getAll();
        //使用SqlSession执行完SQL之后需要关闭SqlSession
        sqlSession.close();
        System.out.println(lstUsers);
    }
}

用到的MyBatisUtil工具类代码如下：

package me.lizhenhua.util;

import java.io.InputStream;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisUtil {

    /**
     * 获取SqlSessionFactory
     * @return SqlSessionFactory
     */
    public static SqlSessionFactory getSqlSessionFactory() {
        String resource = "conf.xml";
        InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource);
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
        return factory;
    }

    /**
     * 获取SqlSession
     * @return SqlSession
     */
    public static SqlSession getSqlSession() {
        return getSqlSessionFactory().openSession();
    }

    /**
     * 获取SqlSession
     * @param isAutoCommit 
     *         true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务
     *         false 表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession.commit()提交事务
     * @return SqlSession
     */
    public static SqlSession getSqlSession(boolean isAutoCommit) {
        return getSqlSessionFactory().openSession(isAutoCommit);
    }
}