如何在springmvc测试中检查JSON响应

我在中定义了一个servlet网站.xml,所以我在一个控制器中定义了它,只用于测试 MyResource

 @Controller 
 public class TestMyServlet {

     MyResource servlet;

     @Autowired
     AutowireCapableBeanFactory beanFac;

     @PostConstruct
     void init() {
         servlet = new MyResource();
         beanFac.autowireBean(servlet);
     }

     @RequestMapping(value = "/servlet/api/update", method = RequestMethod.POST)
     public MyResponse handle(HttpServletRequest request, HttpServletResponse response, @RequestBody String json) {     
         return servlet.update(json);
     }

然后我用 MockHttpServletRequestBuilder

  MockHttpServletRequestBuilder mockHttpServletRequestBuilder = MockMvcRequestBuilders
    .post("/servlet/api/update")
    .content("{\"id\":1,\"toggle\":true}]")
    .session(httpSession)
    .contentType(MediaType.APPLICATION_JSON);
    MvcResult mvcResult = this.mockMvc.perform(mockHttpServletRequestBuilder)
              .andDo(MockMvcResultHandlers.print())
              .andReturn();
    ModelAndView modelAndView = mvcResult.getModelAndView().getModelMap();
    String response = mvcResult.getResponse().getContentAsString();

在servlet中我不使用 ModelAndView MyResponse )即序列化为JSON响应

我的反应 对象作为中的第二个属性 模型和视图 response 为空

如何检查此响应中返回的JSON字符串?