Reactjs Spring 没有正确地将 JSON 序列化为 Java Map

我有一个表单，包含多个无线电输入和一个文本区域输入，我使用axios从ReactJs客户端发送.请求如下所示:

  axios.post("/wellbeing/" + params.wellbeingSurveyType, { formAnswersJson: formAnswers })
    .then(res => {
      // logic
    })
    .catch(err => {
      // logic
    })

The 'formAnswers' object looks like this:

然后，我从Spring控制器接收到如下请求:

    @PostMapping("{wellbeingSurveyType}")
    public WellbeingSurveySubmission submitSurvey(
            @PathVariable WellbeingSurveyType wellbeingSurveyType,
            @RequestBody String formAnswersJson) throws JsonProcessingException {
        var result = new ObjectMapper().readValue(formAnswersJson, HashMap.class);
        return new WellbeingSurveySubmission(); //ignore this
    }

When I call the 'toString()' method on the result object it seems to correctly print out the map values:

But when I try to actually operate on the object (which is parsed as a LinkedHashMap) I cannot access the keys or values:

When I try to open up the object using the debugging tool it seems to store a reference to itself as a value:

我想要的结果就是一张 map &lt；弦，弦&gt；这代表了JSON，但我不确定为什么会发生这种行为.

如果您能提供任何帮助或建议，我们将不胜感激，谢谢.