打开某个特定的url并进行返回相应的字符串

//打开某个特定的url并进行返回相应的字符串。  public synchronized String openUrl(String _url) throws MalformedURLException, IOException {    byte buffer[] = new byte[1024];    StringBuffer result = new StringBuffer();    URL url = new URL(_url);    InputStream is = url.openStream();    boolean done = false;    //读取数据库页面上的数据，并转换为字符串    while (!done) {      int i = is.read(buffer);      if (i != -1) {        String _temp = new String(buffer, 0, i, "UTF-8");        if ("您所请求的网页不存在!".equals(_temp)) {          System.out.println("您所请求的网页不存在!!" + url.toString());          is.close();          return "";        }        result.append(_temp);      }

      else {        done = true;      }    }    //关闭连接    is.close();    return _result;

  }