java对象转json字符串

 案例：

         //创建一个对象
         BeanJpushExtra jpushExtra = new BeanJpushExtra();
                jpushExtra.setShareUser("用户A");
                jpushExtra.setShareDevice("设备A");
                jpushExtra.setShareMsg("分享内容A");

          // java 对象转 json字符串
          net.sf.json.JSONObject json = new net.sf.json.JSONObject();
          String jpushObjec= json.fromObject(jpushExtra).toString();

          //打印出结果
          System.out.println(jpushObjec);

结果：

{
   "shareMsg":"分享内容A",
   "shareDevice":"设备A",
   "shareUser":"用户A"
}