springMvc註解@RequestParam用法解析

一：報錯 

   @ResponseBody

    @RequestMapping("/save")

    public String saveToken(HttpServletRequest request, HttpServletResponse response, @RequestParam String token){*********}

   指定了請求參數，前段未傳token參數過來，會報錯

   報錯信息：HTTP Status 400 - Required String parameter 'token' is not present 

二：解決方式

可以通過required=false或者true來要求@RequestParam配置的前端參數是否一定要傳

1. // required=false表示不傳的話，會給參數賦值爲null，required=true就是必須要有  

2. @ResponseBody
   @RequestMapping("/save")
   public String saveToken(HttpServletRequest request, HttpServletResponse response, @RequestParam(value="token", required = false) String token) {}

   
   

三：使用的坑

  @RequestMapping("testRequestParam")    
  public String filesUpload(@RequestParam(value="aa", required=true) String inputStr,@RequestParam(value="inputInt", required=false) int inputInt ,HttpServletRequest request) {  return "index";}  

解決方法： 

    “Consider declaring it as object wrapper for the corresponding primitive type.”建議使用包裝類型代替基本類型，如使用“Integer”代替“int”