java 发送http请求

String url="";//访问地址String param="";//参数，若是json格式则为"{\"realm\":\"weixin.lenovo.com.cn\"}"，PrintWriter out = null;BufferedReader in = null;String result = "";try {URL realUrl = new URL(url);URLConnection conn =realUrl.openConnection();conn.setDoOutput(true);conn.setDoInput(true);out = new PrintWriter(conn.getOutputStream());// 发送请求参数out.print(param);// flush输出流的缓冲out.flush();// 定义BufferedReader输入流来读取URL的响应in = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));String line;while ((line = in.readLine()) != null) {result += line;}} catch (Exception e) {System.out.println("发送 POST 请求出现异常！"+e);e.printStackTrace();}finally{try{if(out!=null){out.close();}if(in!=null){in.close();}}catch(IOException ex){ex.printStackTrace();}}