java如何获取http请求之后的响应结果

/**

* 获取返回结果

*/

public static String SendGET(String url,String param){

    String result="";//访问返回结果

    BufferedReader read=null;//读取访问结果

    try {

        //创建url

        URL realurl=new URL(url+"?"+param);

        //打开连接

        java.net.URLConnection connection=  realurl.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)");

        //建立连接

        connection.connect();

    // 获取所有响应头字段

        Map> map = connection.getHeaderFields();

    // 遍历所有的响应头字段，获取到cookies等

            //for (String key : map.keySet()) {

    // System.out.println(key + "--->" + map.get(key));}

            // 定义 BufferedReader输入流来读取URL的响应

            read =new BufferedReader(new InputStreamReader(

    connection.getInputStream(),"UTF-8"));

    String line;//循环读取

        while ((line = read.readLine()) !=null) {

    result += line;

}

    }catch (IOException e) {

    e.printStackTrace();

    }finally{

    if(read!=null){//关闭流

                try {

    read.close();

    }catch (IOException e) {

    e.printStackTrace();

    }

    }

}

return result;

}