8.1 简介

​ 底层是反射机制实现与动态代理。

8.2 使用

TestMapper:

package com.yun.test;

import com.yun.pojo.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface TestMapper {

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

mybatis-config.xml:

<?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>
    <properties resource="db.properties"/>

    <typeAliases>
        <package name="com.yun.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${user}"/>
                <property name="password" value="${pwd}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--注册mapper-->
        <mapper class="com.yun.test.TestMapper"/>
    </mappers>
</configuration>

测试接口：

package com.yun.test;

import com.yun.pojo.User;
import com.yun.utils.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class TempTest {
    @Test
    public void tempTest(){
        SqlSession sqlSession = MyBatisUtils.getSqlSession();
        TestMapper testMapper = sqlSession.getMapper(TestMapper.class);
        List<User> userList = testMapper.getUserList();

        for (User user : userList) {
            System.out.println(user);
        }

        sqlSession.close();
    }
}

---

写在最后，使用注解开发，很简便，但是只能用于一些简单的语句，如果是一些复杂的操作，反而会适得其反，使为了简便而生的注解，变得复杂无序。