java跨域后台发送get请求,获取返回值

 @RequestMapping(value = "/subscribeChannel", method = RequestMethod.GET)    @ResponseBody    public String subscribeChannel(String rtmpUrl){        String result="";      try{          if(rtmpUrl ==null || "".equals(rtmpUrl)){              rtmpUrl ="xxxxx请求url";          }          System.out.println("进入视频播放页面："+rtmpUrl);          // 根据地址获取请求          HttpGet request = new HttpGet(rtmpUrl);//这里发送get请求          request.setHeader("Connection","close");          // 获取当前客户端对象          HttpClient httpClient = new DefaultHttpClient();          // 通过请求对象获取响应对象          HttpResponse response = httpClient.execute(request);          // 判断网络连接状态码是否正常(0--200都数正常)          if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {              result= EntityUtils.toString(response.getEntity(),"utf-8");          }else{              result= EntityUtils.toString(response.getEntity(),"utf-8");          }          System.out.println("成功json对象："+result);          if(result == null || "".equals(result)){              result = "{\"data\":{},\"message\":\"请求失败,视频服务器未启动\",\"statusCode\":\"100100\"}";             // throw  new HttpException("播放异常！");          }      }catch (Exception e){         e.printStackTrace();          result = "{\"data\":{},\"message\":\"请求失败，视频服务器未启动\",\"statusCode\":\"100100\"}";       //  throw  new HttpException("播放异常！");      }        return  result;    }