mybatis执行CRUD操作的两种方式配置和注解

Posted 2020-08-09

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

　　userMapper.xml文件的内容如下：

<?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="com.mi.mapping.UserInfoMapper">
    
     <select id="getUser" resultType="com.mi.entity.User">
        SELECT id,user_name userName,age FROM user_t where id=1
    </select>
    
     <!-- 创建用户(Create) -->
    <insert id="addUser" parameterType="com.mi.entity.User">
        insert into user_t(id,user_name,password,age) values(11,#{userName},0,#{age})
    </insert>
    
    <!-- 删除用户(Remove) -->
    <delete id="deleteUser" parameterType="int">
        delete from user_t where id=#{id}
    </delete>
    
    <!-- 修改用户(Update) -->
    <update id="updateUser" parameterType="com.mi.entity.User">
        update user_t set user_name=#{userName},age=#{age} where id=#{id}
    </update>
    
    <!-- 查询全部用户-->
    <select id="getAllUsers" resultType="com.mi.entity.User">
        select * from user_t
    </select>
</mapper>

package com.mi.demo;

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.mi.entity.User;

public class TestCRUDByXmlMapper {

    @Test
    public void testAdd(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        String statement = "com.mi.mapping.UserInfoMapper.addUser";
        User user = new User();
        user.setUserName("xinzhao");
        user.setAge(20);
        
        int insertResult = sqlSession.insert(statement,user);
        sqlSession.close();
        System.out.println(insertResult);
    }
    
    @Test
    public void testUpdate(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        String statement = "com.mi.mapping.UserInfoMapper.updateUser";
        
        User user = new User();
        user.setId(11);
        user.setUserName("xinzhao");
        user.setAge(22);
        int result = sqlSession.update(statement, user);
        sqlSession.close();
        System.out.println(result);
    }
    
    @Test
    public void testDelete(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        String statement = "com.mi.mapping.UserInfoMapper.deleteUser";
        User user = new User();
        user.setId(11);
        int result = sqlSession.delete(statement, user);
        sqlSession.close();
        System.out.println(result);
    }
    
    @Test
    public void testGetAll(){
        SqlSession sqlSession = MyBatisUtil.getSqlSession(true);
        String statement = "com.mi.mapping.UserInfoMapper.getAllUsers";
        List<User> userList = sqlSession.selectList(statement);
        sqlSession.close();
        for(User user : userList){
            System.out.println(user.getUserName());
        }
    }
    
}

二、使用MyBatis对表执行CRUD操作——基于注解的实现

　　1、定义sql映射的接口

　　UserMapper接口的代码如下：

package com.mi.demo;

import java.util.List;

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 com.mi.entity.User;

public interface UserMapper {

    @Insert(" insert into user_t(id,user_name,password,age) values(11,#{userName},0,#{age})")
    public int addUser(User user);
    
    @Delete("delete from user_t where id=#{id}")
    public int deleteById(int id);
    
    @Update("update user_t set user_name=#{userName},age=#{age} where id=#{id}")
    public int update(User user);
    
    @Select("SELECT id,user_name userName,age FROM user_t where id=1")
    public User getById(int id);
    
    @Select("select * from user_t")
    public List<User> getAll();
}

2、在conf.xml文件中注册这个映射接口

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC" />
            <!-- 配置数据库连接信息 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost/mi" />
                <property name="username" value="root" />
                <property name="password" value="dbdaocom" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/mi/mapping/UserInfoMapper.xml"/><!-- 注册userMapper.xml文件， -->
        <mapper class="com.mi.demo.UserMapper"/><!-- 注册UserMapper映射接口-->
    </mappers>
</configuration>

单元测试类的代码如下：

package com.mi.demo;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.mi.entity.User;

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
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setUserName("用户xdp");
        user.setAge(20);
        int result = mapper.addUser(user);
        sqlSession.close();
        System.out.println(result);
    }
    /**
     * ...the end
     */
}

用到的MyBatisUtil工具类代码如下：

package com.mi.demo;

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() {
        // mybatis的配置文件
        String resource = "conf.xml";
        // 使用类加载器加载mybatis的配置文件（它也加载关联的映射文件）
        InputStream is = Test1.class.getClassLoader().getResourceAsStream(resource);
        // 构建sqlSession的工厂
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(is);
        return sessionFactory;
    }

    /**
     * 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);
    }
}