Map<String,String> map = new HashMap<String,String>();

 Enumeration<Object> keys = properties.keys();

 while(keys.hasMoreElements()){

     String key = (String)keys.nextElement();

     String value = (String)properties.get(key);

     map.put(key,value);

 }

 Gson gson = new Gson();

 String jsonStr = gson.toJson(map);

 //以下是传输到调用页面
 PrintWriter pw = response.getWriter();

 pw.print(jsonStr);

 pw.flush();