如何用Java检查URL是否存在或返回404？
如何用Java检查URL是否存在或返回404？
提问于 2009-09-04 09:38:51
String urlString = "http://www.nbc.com/Heroes/novels/downloads/Heroes_novel_001.pdf";
URL url = new URL(urlString);
if(/* Url does not return 404 */) {
System.out.println("exists");
} else {
System.out.println("does not exists");
}
urlString = "http://www.nbc.com/Heroes/novels/downloads/Heroes_novel_190.pdf";
url = new URL(urlString);
if(/* Url does not return 404 */) {
System.out.println("exists");
} else {
System.out.println("does not exists");
}这应该会打印出来
exists
does not exists测试
public static String URL = "http://www.nbc.com/Heroes/novels/downloads/";
public static int getResponseCode(String urlString) throws MalformedURLException, IOException {
URL u = new URL(urlString);
HttpURLConnection huc = (HttpURLConnection) u.openConnection();
huc.setRequestMethod("GET");
huc.connect();
return huc.getResponseCode();
}
System.out.println(getResponseCode(URL + "Heroes_novel_001.pdf"));
System.out.println(getResponseCode(URL + "Heroes_novel_190.pdf"));
System.out.println(getResponseCode("http://www.example.com"));
System.out.println(getResponseCode("http://www.example.com/junk")); 输出
200
200
200
404
解决方案
在.connect()之前添加下一行，输出将是200,404,200,404
huc.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)");回答 5
Stack Overflow用户
发布于 2009-09-04 11:14:07
您可能想要添加
HttpURLConnection.setFollowRedirects(false);
// note : or
// huc.setInstanceFollowRedirects(false)如果您不想遵循重定向(3XX)
你只需要一个“头”，而不是"GET“。
huc.setRequestMethod("HEAD");
return (huc.getResponseCode() == HttpURLConnection.HTTP_OK);Stack Overflow用户
发布于 2011-04-22 01:39:41
这对我很有效：
URL u = new URL ( "http://www.example.com/");
HttpURLConnection huc = ( HttpURLConnection ) u.openConnection ();
huc.setRequestMethod ("GET"); //OR huc.setRequestMethod ("HEAD");
huc.connect () ;
int code = huc.getResponseCode() ;
System.out.println(code);感谢上面的建议。
Stack Overflow用户
发布于 2009-09-04 09:40:09
通过在URL对象上调用openConnection()来使用HttpUrlConnection。
一旦你从连接中读取，getResponseCode()就会给你超文本传输协议响应。
例如：
URL u = new URL("http://www.example.com/");
HttpURLConnection huc = (HttpURLConnection)u.openConnection();
huc.setRequestMethod("GET");
huc.connect() ;
OutputStream os = huc.getOutputStream();
int code = huc.getResponseCode(); (未测试)
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/1378199
复制相关文章
相似问题
腾讯云开发者
