@RequestMapping("byLabel")
 public ResponseEntity<List<Topic>> findTopicsbyLabel(
     HttpServletRequest request, @RequestParam String labelname) throws Exception {
   labelname = new String(labelname.getBytes("iso-8859-1"), "utf-8");
   List<Topic> topics = topicDao.findTopicByLabelName(labelname, 1);
   return new ResponseEntity<List<Topic>>(topics, HttpStatus.OK);
 }
 @RequestMapping("bySubject")
 public ResponseEntity<List<Topic>> findTopics(
     HttpServletRequest request, @RequestParam String subject) throws Exception {
   subject = new String(subject.getBytes("iso-8859-1"), "utf-8");
   List<Topic> topics = topicDao.findTopicBySubject(subject, 1);
   return new ResponseEntity<List<Topic>>(topics, HttpStatus.OK);
 }
 @RequestMapping("leaveTopic")
 public String leaveTopic(@RequestParam String client_id, @RequestParam String huanxin_group_id) {
   User user = new User();
   Topic topic = new Topic();
   topic.setHuanxin_group_id(huanxin_group_id);
   user.setClient_id(client_id);
   topicDao.userLeaveTopic(user);
   return "SUCCESS";
 }
 @RequestMapping("addTopic")
 public String addTopic(
     HttpServletRequest request,
     @RequestParam String client_id,
     @RequestParam String huanxin_group_id,
     @RequestParam String subject,
     @RequestParam String label_name)
     throws Exception {
   request.setCharacterEncoding("UTF-8");
   User user = new User();
   user.setClient_id(client_id);
   Label label = new Label();
   label.setLabel_name(label_name);
   Topic topic = new Topic();
   topic.setHuanxin_group_id(huanxin_group_id);
   topic.setLabel(label);
   topic.setUser(user);
   topicDao.save(topic);
   return "success";
 }
 @RequestMapping("byUser")
 public ResponseEntity<List<Topic>> findTopicsbyUserl(
     HttpServletRequest request, @RequestParam String client_id) throws Exception {
   List<Topic> topics = topicDao.findTopicByUserId(client_id, 1);
   return new ResponseEntity<List<Topic>>(topics, HttpStatus.OK);
 }