Json（二）之 java 操作 Json

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在java中使用，第三方工具解析 JSON：把一个javaBean对象创建成json对象

开发步骤：看下面两张图片

第一步：导包，百度一下json包，全部导入就可以
第二部：了解两个类方法
      JSONArray.fromObject(javaBean对象)
              //设置javaBean转化成json时，不包含某个字段
             JsonConfig jsonConfig = new JsonConfig();
              jsonConfig.setExcludes(new String[]{“id”});
              JSONArray jsonArray = JSONArray.fromObject(provinceList,jsonConfig);

这里写图片描述

//注意这里的ajax.jsp代码不变。//改变的是servlet传递数据的方式CityServlet1  public void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        String province = request.getParameter("province");        byte[] buf = province.getBytes("ISO8859-1");        province = new String(buf,"UTF-8");        response.setContentType("text/html;charset=UTF-8");        PrintWriter pw = response.getWriter();        String jsonString = null;        List<City> cityList = new ArrayList<City>();        if(province.equals("吉林省")){            cityList.add(new City(1,"长春"));            cityList.add(new City(2,"吉林市"));            cityList.add(new City(3,"松原"));            cityList.add(new City(4,"通化"));        }else if(province.equals("辽宁省")){            cityList.add(new City(1,"沈阳"));            cityList.add(new City(2,"大连"));            cityList.add(new City(3,"鞍山"));            cityList.add(new City(4,"抚顺"));            cityList.add(new City(5,"铁岭"));        }else if(province.equals("山东省")){            cityList.add(new City(1,"济南"));            cityList.add(new City(2,"青岛"));            cityList.add(new City(3,"威海"));        }else{            cityList.add(new City(1,"xx"));            cityList.add(new City(2,"xx"));            cityList.add(new City(3,"xxx"));        }        //设置去掉javaBean中的id.这个id多余就不要生成Json了        JsonConfig jsonConfig = new JsonConfig();        jsonConfig.setExcludes(new String[]{"id"});        JSONArray jsonArray = JSONArray.fromObject(cityList, jsonConfig);        //注意哦，返回的值是字符串，所以应该把数组输出。不能直接返回JsonArray        jsonString = jsonArray.toString();        System.out.println(jsonArray.toString());        pw.write(jsonString);    }

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