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,输出将为 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)");
最佳答案
你可能想添加
HttpURLConnection.setFollowRedirects(false);
// note : or
// huc.setInstanceFollowRedirects(false)
如果你不想跟随重定向 (3XX)
您只需要一个“HEAD”而不是“GET”。
huc.setRequestMethod("HEAD");
return (huc.getResponseCode() == HttpURLConnection.HTTP_OK);
关于java - 如何检查 URL 是否存在或使用 Java 返回 404?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/1378199/