1.结论,xml中返回为string的话,在list中只会取出来第一个元素

  //根据value查询
    @GetMapping("getTest")
    public List<HashMap> getTest() {
        List<HashMap> list = dictService.getTest();
        return list;
    }

<select id="getTest" resultType="java.lang.String">
select * from t_test
</select>

mybatis-plus.mapper-locations =classpath*:mapper/**/*Mapper.xml