SpringMVC报错:The given id must not be null

普通看这个错误肯定是入参id为空了, 但是有一种情况是你入参没有id这个参数, 系统还是报这个错误, 比如如下代码

 @RequestMapping(
            value = "/messages/{userId}",
            method = RequestMethod.GET,
            produces = MediaType.APPLICATION_JSON_VALUE
    )
    public PageData getMessages(
            @PathVariable String userId,
            @RequestParam(value = "page", required = false, defaultValue = "0") int page,
            @RequestParam(value = "size", required = false, defaultValue = "20") int size
    ) {
        SecurityUtil.checkIsUserHimself(userId);
        List messages = appMessageService.getMessages(page, size, userId);
        fetchProfile(messages);
        return new PageData<>(page, size, (appMessageService.countMessage(userId) / size) + 1, messages);
    }

以上代码的入参是userId, 但是项目任然报这个错误!

 

问题根源:

这个时候去检查下面的代码, springData的接口中只要你用了主键(索引)去查数据,那么springmvc也会报这个错误!