session里一个ID会取出的1个对象里有多行数据

问题一：：一ID取出多行;session里一个ID会取出的1个对象里有多行数据，服务器更新后，导致客户端都500，恢复后，都卡在登录界面，

2019-12-24 00:20:21.935 ERROR com.ahlinksoft.wx.OAuth2.OAuth2Service Line:53  - 拉取微信网页授权AccessToken失败，错误信息：{"errcode":40163,"errmsg":"code been used, hints: [ req_id: J.LFHzyFe-_zlwWa ]"}
2019-12-24 00:20:21.938 INFO  p6spy Line:62  - 12:20:21,938|0|rollback|connection 4||
java.lang.NullPointerException
        at com.ahlinksoft.school.service.GuardianService.loginByPhone(GuardianService.java:98)

问题二：：

   @Transactional(propagation = Propagation.REQUIRED,isolation = Isolation.DEFAULT,timeout=36000,readOnly=true)
    public ServiceFee getDefaultServiceFeeDtoByStudentId(StudentDto studentDto){

return  ((ServiceFeeService) serviceFeeMapper).getDefaultServiceFeeDtoByStudentId(studentDto);

java.lang.ClassCastException: com.sun.proxy.$Proxy79 cannot be cast to com.ahlinksoft.pay.service.ServiceFeeService