1，將實體類的每個屬性以鍵值對的形式發到map中 

           ErrorCode code =new ErrorCode(1, "SUCCESS");
    	 
    	   JSONObject json=JSONObject.fromObject(code);
    	   Map<String, String> map = new HashMap<String, String>();
    	   map.putAll(json);
    	   Iterator it = map.entrySet().iterator();
    	   while (it.hasNext()) {
    	   Map.Entry entry = (Map.Entry) it.next();
    	   Object key = entry.getKey();
    	   Object value = entry.getValue();
    	   System.out.println("key=" + key + " value=" + value);
    	  }
 

2，將json字串轉為實體類物件

  @org.junit.Test
    public void test4(){
    	GetCardNoInHospitalResp respdata=new GetCardNoInHospitalResp();
    	String response="{'message':'SUCCESS','data':{'cardNo':'12345','code':0,'message':''},'code':'0'}";
    	JSONObject json = JSONObject.fromObject(response);
    	JSONObject data=(JSONObject) json.get("data");
    	respdata=com.alibaba.fastjson.JSONObject.parseObject(data.toString(), GetCardNoInHospitalResp.class);
    	System.out.println(respdata.getCardNo());
    } 
 

 3.將實體類轉化為json字串

jsonObject = JSONObject.fromObject("物件");

4.將json字串輸出到頁面

protected void jsonObj(String jobj) {
		try {
			response.setCharacterEncoding("UTF-8");
			response.setHeader("Cache-Control", "no-cache");
			response.setContentType("application/json; charset=UTF-8");
			response.getWriter().write(jobj);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}