MyBatis return Map, query field two as a key and value, respectively,

Wrote a blog before, MyBatis return a result of type Map ( https://blog.csdn.net/Dongguabai/article/details/79580200 ), this direct return results Map, the result returned is this:

The result is a return Map, Map of Entry for the "field name - field value, the field name - field value."

But sometimes we need is the return of key-value, key and value are two mapping relational data returned. This time you can do:

Custom Handler achieve ResultHandler:

/**
 * @author dongguabai
 * @Description
 * @Date 创建于 2019-05-15 22:14
 */
public class MapResultHandler implements ResultHandler {
    private final Map mappedResults = new HashMap();

    @Override
    public void handleResult(ResultContext context) {
        @SuppressWarnings("rawtypes")
        Map map = (Map)context.getResultObject();
        mappedResults.put(map.get("key"), map.get("value"));
    }

    public Map getMappedResults() {
        return mappedResults;
    }
}

Mapper (time to address the situation when a method with parameters, where a query Query added):

public interface UserAccountMapper extends BaseMapper<UserAccount> {

    Map<String,String> testType(UserQuery query);
}

xml：

<?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.zj.bda.persistence.mapper.UserAccountMapper">


    <resultMap id="mapResult" type="java.util.HashMap">
        <result property="key" column="username"/>
        <result property="value" column="balance" />
    </resultMap>

    <select id="testType" parameterType="com.zj.bda.persistence.query.UserQuery" resultMap="mapResult">
        select username,balance from user_account where username = #{username} and balance = #{balance}

    </select>

</mapper>

database:

test:

/**
 * @author Dongguabai
 * @date 2018/10/8 10:25
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootSpringTest {

    @Autowired
    private SqlSessionFactory sqlSessionFactory;

    @Test
    public void test2(){
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        MapResultHandler handler = new MapResultHandler();
        UserQuery userQuery = new UserQuery("zhangsan",2000);
        sqlSession.select("com.zj.bda.persistence.mapper.UserAccountMapper.testType",userQuery,handler);
        //获取结果
        handler.getMappedResults().forEach((k,v)-> System.out.println("k:"+k+",v:"+v));
    }}

MyBatis return Map, query field two as a key and value, respectively,

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