将Java对象转换为JSONObject并以GET方法传输它. [英] Converting Java object to JSONObject and transmit it at GET method.

问题描述

• 我正在开发一个Android应用程序，为此我还正在开发一个 基于Spring-MVC的服务器.不幸的是，在此之前，我还没有做过 在JSONObjects上做了很多工作.目前，我可以发送Java 对象从Android应用程序发送到服务器，并接收Java对象 也.
  • 我对使用Google提供的Volley框架感兴趣， 这样可以避免Asynctask的麻烦，并且效率更高，但是 它处理JSONObject.
  • 不幸的是，无论我在网上看什么，我都找到了以下代码: 创建JSOnObjects以将其保存在本地硬盘驱动器上的某个文件中，但是 不，我想在ResponseBody中传送它们，有人可以帮我吗 首先创建一个JSOBObject的JAVA对象，反之亦然.我有 所有POM依赖项，以及在Servlet上下文中设置的messageConvertors.
  • I am working on an Android app, for which I am also working on a Spring-MVC based server. Unfortunately before this, I have not done that much work on JSONObjects. Currently, I am able to send Java objects to the server from the Android app, and receive Java objects too.
    • I am interested in using the Volley framework provided by Google, which will avoid the hassle of Asynctask and is more efficient, but it deals with JSONObject.
    • Unfortunately wherever I looked on the net, I found the code to create JSOnObjects to save it in some file on Local Hard drive, but no, I would like to transmit them in ResponseBody, can anyone help me out with creating a JAVA object to JSOBObject and vice-versa. I have all POM dependencies, and messageConvertors set in servlet-context.

    当前控制器代码:

    //Restaurant is just a plain Java class, I can give it as a JSONObject, but I dont know how to convert that JSONObject to java so I can save the restaurant in the server.
     @RequestMapping(value = "/restaurant/add",method = RequestMethod.POST)
        @ResponseBody
        public String addRestaurantWebView(@RequestBody Restaurant restaurant){
            ModelAndView modelAndView = new ModelAndView();
            modelAndView.addObject("restaurant", new Restaurant());
            modelAndView.addObject(restaurant);
            this.restaurantService.addRestaurant(restaurant);
            return "true";
        }
    
    //Similarly, here, I don't know how to convert the Restaurant's list to JSONObject when there is a get Request. 
        @RequestMapping(value = "/restaurant/listing", method = RequestMethod.GET)
        public @ResponseBody List<Restaurant> listAllRestaurants(){
            ModelAndView modelAndView = new ModelAndView();
            modelAndView.addObject("restaurant", new Restaurant());
            List<Restaurant> restaurantList = this.restaurantService.listRestaurants();
            modelAndView.addObject("listRestaurant", restaurantList);
            return restaurantList;
        }
    

    我希望我的问题很清楚，如果有任何疑问，请告诉我.非常感谢.

    I hope my question was clear, if there is any doubt, please let me know. Thanks a lot.

    推荐答案

    看看 Google的格森(Gson).这是一个非常简洁的API，用于将对象转换为JSON.通过将类中的@Expose批注添加到需要包括的属性中，可以轻松地指定属性.像这样尝试:

    Take a look at Google's Gson. It's a pretty concise API for converting objects to JSON. You can easily specify properties by adding the @Expose annotation in your classes to the properties you need to include. Try it like this:

    @RequestMapping(value = "/restaurant/listing", method = RequestMethod.GET)
    public @ResponseBody String listAllRestaurants(){
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.addObject("restaurant", new Restaurant());
        List<Restaurant> restaurantList = this.restaurantService.listRestaurants();
    
        Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation().create();
        String jsonString = gson.toJson(restaurantList);
    
        return jsonString;
    }
    

    不必使用@Expose注释属性，但如果最终有任何循环引用，这将有所帮助.

    It's not necessary to annotate properties with @Expose but it will help if you end up having any circular references.

    祝你好运.

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