java测试URL是否连通的方法

private boolean canGetHtmlCode(String httpUrl) {

  String htmlCode = "";

  try {

   InputStream in;

   URL url = new java.net.URL(httpUrl);

   HttpURLConnection connection = (HttpURLConnection) url.openConnection();

   connection = (HttpURLConnection) url.openConnection();

   connection.setRequestProperty("User-Agent", "Mozilla/4.0");

   connection.connect();

   in = connection.getInputStream();

   byte[] buffer = new byte[50];

   in.read(buffer);

   htmlCode = new String(buffer);

  } catch (Exception e) {

  }

  if (RmStringHelper.empty(htmlCode) || htmlCode.equals("")) {

           return false;

  }

  return true;

 }