java http request&respone

/**
     * http 发送请求
     * @param params 参数
     * @param sendType 接口类型
     * @return 结果代码
     */
    private static String httpSend(Map<String,String> params,String sendType){
        StringBuffer result = new StringBuffer();
        try
        {
            String urlPath=ReadPropertiesUtil.getUrl()+sendType;
            URL url = new URL(urlPath);
            URLConnection rulConnection = url.openConnection();
            HttpURLConnection httpUrlConnection = (HttpURLConnection) rulConnection;
            httpUrlConnection.setDoOutput(true);   
            httpUrlConnection.setDoInput(true);   
            httpUrlConnection.setUseCaches(false);
            httpUrlConnection.setConnectTimeout(30000);   
            httpUrlConnection.setReadTimeout(30000);
            //httpUrlConnection.setRequestProperty("Content-type", "application/x-java-serialized-object");   
            httpUrlConnection.setRequestMethod("POST");
            httpUrlConnection.connect();  
            //request
            OutputStream outStrm = httpUrlConnection.getOutputStream(); 
            String param = "";
            Set<String> keys=params.keySet();
            for(Iterator<String> iter=keys.iterator();iter.hasNext();){
                String key=iter.next();
                String msg=URLEncoder.encode(params.get(key)==null?"":params.get(key),ENCODE);
                param+=key+"="+ msg +"&";
            }
            if(param.length()>0){
                param=param.substring(0, param.lastIndexOf('&'));
            }
            outStrm.write(param.getBytes());  
            outStrm.flush();
            outStrm.close();
            //respone
            BufferedReader br = new BufferedReader(new InputStreamReader(httpUrlConnection.getInputStream()));
            String readLine;
            while((readLine = br.readLine()) != null){
                result.append(readLine);
            }
            br.close();
            httpUrlConnection = null;
        } catch (Exception e)
        {
            e.printStackTrace();
        }
        return result.toString();
    }