检查URL是否存在 [英] Checking if a URL exists or not

问题描述

我需要检查网址是否存在。我想为此编写一个servlet，即检查URL是否存在。如果输入的URL不存在，那么它应该返回一些消息。

I need to check whether a URL exists or not. I want to write a servlet for this i.e. to check whether a URL exists or not. If the URL entered does not exist, then it should return some message.

推荐答案

更好的HTTP解决方案：

Better solution for HTTP :

public static boolean exists(String URLName){
    try {
      HttpURLConnection.setFollowRedirects(false);
      // note : you may also need
      //        HttpURLConnection.setInstanceFollowRedirects(false)
      HttpURLConnection con =
         (HttpURLConnection) new URL(URLName).openConnection();
      con.setRequestMethod("HEAD");
      return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
    }
    catch (Exception e) {
       e.printStackTrace();
       return false;
    }
  }  

如果您正在寻找任何其他网址，请尝试使用此代码

If you are looking for any other URL try this code

  public static boolean exists(String URLName){
      boolean result = false;
      try {
          url = new URL("ftp://ftp1.freebsd.org/pub/FreeBSD/");
          //url = new URL("ftp://ftp1.freebsd.org/pub/FreeBSD123/");//this will fail

          input = url.openStream();

           System.out.println("SUCCESS");
           result = true;

            } catch (Exception ex) {
               Logger.getLogger(NewClass.class.getName()).log(Level.SEVERE, null, ex);
            }
         return result;
  }

来源：http：//www.rgagnon .com / javadetails / java-0059.html

Source :http://www.rgagnon.com/javadetails/java-0059.html

这篇关于检查URL是否存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！