spring mvc $.ajax没有指定contentType ，导致后台无法接收到数据

var formData = JSON.stringify(this.rows);  //将表单中的数据转为字符串

$.ajax({
       type: "post",
       url: ‘http://localhost:8080/data‘,
       data:formData,
       dataType:"json",
       contentType: "application/json;charset=utf-8",  
       success: function (data) {
      }
});  //开始漏掉了标红的属性设置，导致后台始终无法解析数据，能收到数据，但是很有乱七八糟的字符。

    @RequestMapping(value = "/data",method = RequestMethod.POST)
    public void getData(@RequestBody String str) throws IOException{
        org.codehaus.jackson.map.ObjectMapper mapper = new org.codehaus.jackson.map.ObjectMapper();
        JavaType javaType = mapper.getTypeFactory().constructParametricType(ArrayList.class, TestModel.class);
        List<TestModel> list =  (List<TestModel>)mapper.readValue(str, javaType);
        System.out.println(str);
        System.out.println(list);
    }

    @RequestMapping(value = "/data",method = RequestMethod.POST)
    public void getData(@RequestBody LIst<TestModel> list)