Mybatis Map<>接收参数导致类型转换错误

List<Map<String,String>> maps = todoMapper.seletLineDate();
// 此时的状态是List<Map<String,Object>> 
Map<String, String> mapto = new HashMap<>();
for (Map<String, String> map : maps) {
    mapto.put(map.get("time"), map.get("number"));
}
// 此时的状态是Map<String,Long>

如果用Map<String,String>接返回值，会报Long转String的类型错误

<select id="seletLineDate" resultType="map">
    select COUNT(task_uuid) number, end_date time
    from todo
    where user_uuid = #{userUuid}
    and done = true
    and end_date between #{startTime} and #{endTime}
    group by end_date
    order by end_date
</select>

原因是COUNT返回的Number类型会和Java的Long类型进行匹配

List<Map<String,String>> seletLineDate(String startTime, String endTime, String userUuid);

当Mapper层用Map<String,String>接数据时,仍然返回Map<String,Long>只是明面上是Map<String,String>

修改方法

用Object去接，或者转换COUNT的返回结果，CONVERT(COUNT(task_uuid),CHAR)

PS：

该错误在编辑时不会报错,但是在运行时会报错