使用MyBatis进行CURD操作

发表于 2017-09-28 分类于 Java Valine：
本文字数： 6.7k 阅读时长 ≈ 6 分钟

概述

在上一篇文章MyBatis 配置详解中已经详细地介绍了MyBatis的配置环境，算是对MyBatis有了初步的理解了。今天讲下如何使用MyBatis对数据表进行进行增删改查，本文使用的测试环境是上一篇文章中的测试环境。

基于XML文件的实现

在mapper.xml文件中写入操作语句，代码如下：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="domain.userMapper">
    <!--parameterType为传入的数据类型，resultType为结果数据类型，resultType="com.domain.User"表示将结果封装成一个User类-->
    <select id="getUser" parameterType="int" resultType="com.domain.User">
        SELECT * FROM user WHERE id = #{id}
    </select>
    <insert id="insertUser" parameterType="com.domain.User" >
        INSERT INTO user(id,name,age) VALUES (#{id},#{name},#{age})
    </insert>
    <delete id="deleteUser" parameterType="int">
        DELETE FROM user WHERE id = #{id}
    </delete>
    <update id="updateUser" parameterType="com.domain.User">
        UPDATE user SET name=#{name} ,age=#{age} WHERE id = #{id}
    </update>
    <select id="getAllUsers" resultType="com.domain.User">
        SELECT * FROM user;
    </select>
</mapper>

测试代码如下：

import com.domain.User;
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.testng.annotations.BeforeSuite;
import org.testng.annotations.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestCURD {

    @BeforeSuite
     private SqlSession before() throws IOException {
        String resource = "config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        return sqlSessionFactory.openSession();
    }

    @Test
    public void testInsert() throws IOException {
        SqlSession session = before();
        User user = new User();
        user.setName("dysmorsel");
        user.setAge(18);
        user.setId(3);
        try {
            //根据mapper.xml内的命名空间和方法id找到相应的方法，传入参数
            int result = session.insert("domain.userMapper.insertUser",user);
            //手动提交
            session.commit();
            //打印结果参数，0为失败，1为成功
            System.out.println(result);
        }finally {
            //操作结束，关闭session
            session.close();
        }
    }

    @Test
    public void testDelete() throws IOException {
        SqlSession session = before();

        try {
            int result = session.delete("domain.userMapper.deleteUser",3);
            session.commit();
            System.out.println(result);
        }finally {
            session.close();
        }
    }

    @Test
    public void testSelect() throws IOException {
        SqlSession session = before();

        try{
            User user = session.selectOne("domain.userMapper.selectUser",3);
            System.out.println(user);
        }finally {
            session.close();
        }
    }

    @Test
    public void testUpdate() throws IOException {
        SqlSession session = before();
        User user = new User();
        user.setName("dysmorsel");
        user.setAge(22);
        user.setId(3);
        try {
            int result = session.insert("domain.userMapper.updateUser",user);
            session.commit();
            System.out.println(result);
        }finally {
            //操作结束，关闭session
            session.close();
        }
    }

    @Test
    public void testGetAll() throws IOException {
        SqlSession session = before();
        //执行查询操作，将查询结果自动封装成List<User>返回
        List<User> users = session.selectList("domain.userMapper.getAllUsers");
        System.out.println(users);
        session.close();
    }

}

基于接口方法的实现

在UserMapperj接口中写入操作语句，代码如下：

package com.mapping;

import com.domain.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

import java.util.List;

/**
 * 定义sql映射的接口，使用注解指明方法要执行的SQL
 */
public interface UserMapper {
    @Select(value = "SELECT * FROM user WHERE id = #{id} ")
     User findById(int id);

    @Insert(" INSERT INTO user(id,name,age) VALUES (#{id},#{name},#{age})")
    int insertUser(User user);

    @Delete("delete from user where id=#{id}")
    int deleteById(int id);

    @Update("update user set name=#{name},age=#{age} where id=#{id}")
    int update(User user);

    @Select("select * from user")
    List<User> getAll();

}

测试代码如下：

import com.domain.User;
import com.mapping.UserMapper;
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.testng.annotations.BeforeSuite;
import org.testng.annotations.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestCURD {

    @BeforeSuite
     private SqlSession before() throws IOException {
        String resource = "config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        return sqlSessionFactory.openSession();
    }

    @Test
    public void testInsert() throws IOException {
        SqlSession session = before();
        User user = new User();
        user.setName("dysmorsel");
        user.setAge(18);
        user.setId(3);
        try {
            UserMapper mapper = session.getMapper(UserMapper.class);
            //根据mapper.xml内的命名空间和方法id找到相应的方法，传入参数
            int result = mapper.insertUser(user);
            session.commit();
            //打印结果参数，0为失败，1为成功
            System.out.println(result);
        }finally {
            //操作结束，关闭session
            session.close();
        }
    }

    @Test
    public void testDelete() throws IOException {
        SqlSession session = before();

        try {
            UserMapper mapper = session.getMapper(UserMapper.class);
            int result = mapper.deleteById(3);
            session.commit();
            System.out.println(result);
        }finally {
            session.close();
        }
    }

    @Test
    public void testSelect() throws IOException {
        SqlSession session = before();

        try{
            UserMapper mapper = session.getMapper(UserMapper.class);
            User user = mapper.selectUser(3);
            System.out.println(user);
        }finally {
            session.close();
        }
    }

    @Test
    public void testUpdate() throws IOException {
        SqlSession session = before();
        User user = new User();
        user.setName("dysmorsel");
        user.setAge(22);
        user.setId(3);
        try {
            UserMapper mapper = session.getMapper(UserMapper.class);
            int result = mapper.update(user);
            session.commit();
            System.out.println(result);
        }finally {
            //操作结束，关闭session
            session.close();
        }
    }

    @Test
    public void testGetAll() throws IOException {
        SqlSession session = before();
        UserMapper mapper = session.getMapper(UserMapper.class);
        //执行查询操作，将查询结果自动封装成List<User>返回
        List<User> users = mapper.getAll();
        System.out.println(users);
        session.close();
    }

}

以上的相关代码是全部测试通过的，使用MyBatis对表执行CRUD操作的内容基本就是这些。

本文作者： LightYears
本文链接： https://lyears.github.io/2017/09/28/Java/10/
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