报错One record is expected, but the query result is multiple records

总结：出现这种情况，显而易见，就是查询的数据在数据库中不止一条，而我调用的selectOne方法，返回值是一个User对象，导致报错

点击查看错误代码

LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(StringUtils.isNotBlank(userId), User::getUserId, userId);
User user = userMapper.selectOne(queryWrapper);

点击查看报错信息

com.baomidou.mybatisplus.core.exceptions.MybatisPlusException: One record is expected, but the query result is multiple records
	at com.baomidou.mybatisplus.core.toolkit.ExceptionUtils.mpe(ExceptionUtils.java:49)
	at com.baomidou.mybatisplus.core.mapper.BaseMapper.selectOne(BaseMapper.java:176)
	at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy$DefaultMethodInvoker.invoke(MybatisMapperProxy.java:162)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:89)
	at com.sun.proxy.$Proxy119.selectOne(Unknown Source)
	at com.xxxxx.taview.mcn.service.impl.McnUserServiceImpl.getMcnUserById(McnUserServiceImpl.java:41)
	at com.xxxxx.taview.mcn.controller.McnUserController.getMcnUserByUSerID(McnUserController.java:39)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150)