ajax請求springmvc成功後仍然執行error模塊

1.前臺

 $.ajax({
             method:'post',
             data:jsonStr,
             url:'xxxxx/good',
             contentType: "application/json; charset=utf-8",
             dataType: "json", 
             success:function(result){
             },
             error: function(XMLHttpRequest, textStatus, errorThrown) {
                 alert(XMLHttpRequest.status);
                 alert(XMLHttpRequest.readyState);
                 alert(textStatus);
             }
         });

2.springmvc

    @ResponseBody
    @RequestMapping(value={"good",""})
    public String savetobt(@RequestBody String jsonStr){
        List<BigDelay> list=JsonUtil.fromJson(jsonStr, List.class);

        return "";

    }

3.出現問題
ajax請求springmvc成功後仍然執行error模塊，分別彈出200， 4，parsererror
3.問題原因
springmvc返回的結果不是json類型的數據
4.解決辦法：改返回類型

    @ResponseBody
    @RequestMapping(value={"good",""})
    public String savetobt(@RequestBody String jsonStr){
        List<BigDelay> list=JsonUtil.fromJson(jsonStr, List.class);
        System.out.println(list);
        String jsonResult=JsonUtil.toJson("");
        return jsonResult;

    }