在后台程序中发送http请求并获取响应数据

　　　　 String result="";
        BufferedReader in = null;
        URL url = null;
        try {
            url = new URL("http://libs.baidu.com/jquery/2.0.0/jquery.min.js");
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        //打开连接
        URLConnection connection = url.openConnection();
        
        // 设置通用的请求属性
        connection.setRequestProperty("accept", "*/*");
        connection.setRequestProperty("connection", "Keep-Alive");
        connection.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        // 建立实际的连接
        connection.connect();
        
        // 定义 BufferedReader输入流来读取URL的响应
        in = new BufferedReader(new InputStreamReader(
                connection.getInputStream()));
        //写出数据
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
        //关流
        in.close();
        System.out.println(result);