### 1. 写错resultMap ~~~ <!--BaseResultMap--> <select id="getRoleIdsByUserName" parameterType="string" resultMap="SysroleMapper"> SELECT s.roleId FROM SysUserRole s INNER JOIN UserInfo u ON s.uid = u.uid WHERE u.username=#{userName} </select> ~~~ 报错，整个DAO都不能进行查询 java.lang.IllegalArgumentException: Result Maps collection does not contain value for com.aixin.mapper.SysroleMapper.SysroleMapper