MapHandler把一条sql的记录封装到map中,列名是key,值是value
比如:id=2,name=xiaoming,password=123456;
MapListHandler把一条sql的记录封装到map中,把多个map放入List集合当中
具体的实现过程和下面这篇文章类似
https://blog.csdn.net/qq_41901915/article/details/86493555
https://blog.csdn.net/qq_41901915/article/details/86493555