Mybatis 查寻结果返回 Map、List〈Map〉

通常情况下，我们的查寻返回结果都会填充进相应的实体类中。
但有些特殊情况，我们返回的结果可能不是固定类型，这时可以使用 Map， List

com.jerry.mapper.TestMapper.java

package com.jerry.mapper;

import java.util.List;
import java.util.Map;

public interface TestMapper {
	/**
	 * 查寻单个结果直接返回 Map<String, Object>
	 * @param id
	 * @return
	 */
	Map<String, Object> selectById(Long id);
	
	/**
	 * 查寻结果列表返回 List<Map<String, Object>>
	 * @param paramsMap
	 * @return
	 */
	List<Map<String, Object>> selectList(Map<String, Object> paramsMap);
}

com.jerry.mapper.TestMapper.xml

<select id="selectById" resultType="map" parameterType="java.lang.Long">
	select * 
	from test_table as tt
	where tt.id = #{id}
</select>

<select id="selectList" resultType="map" parameterType="map">
	select * 
	from test_table as tt
	<trim prefix="WHERE" prefixOverrides="AND |OR ">
		<!-- 关键字查询 -->
		<if test="keyWords != null and keyWords != ''">
			AND (
				   IFNULL(tt.title, "") like "%"#{keyWords}"%"
				or IFNULL(tt.keys, "") like "%"#{keyWords}"%"
			 )
		</if>
		<if test="searchType != null and searchType != ''">
			AND tt.searchType = #{searchType}
		</if>
	</trim>
</select>

com.jerry.service.impl.TestService.java

package com.jerry.service.impl;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
@Transactional(readOnly = true)
public class TestService implements ITestService {
	
	@Resource
	private TestMapper testMapper;

	@Override
	public Map<String, Object> allSearch(String keyWords, Integer searchType) {
		Map<String, Object> paramsMap = new HashMap<>();
		paramsMap.put("keyWords", keyWords);
		paramsMap.put("searchType", searchType);
		List<Map<String, Object>> list = testMapper.listSearch(paramsMap);
		return list.get(0);
	}

}