URLConnection抛出FileNotFoundException。 我怎么发现这是由404引起的？

Question

I've got this code:

String buildUrl = DEFAULT_HOST + "/job/" + jobName + "/" + buildNumber + API_PATH;
URLConnection connection = new URL(buildUrl).openConnection();
InputStream is = connection.getInputStream();

If that buildUrl results in a 404 response, that last line throws a FileNotFoundException . But, I want to know that the server returned a 404 because I don't trust that FileNotFoundException always means 404 and I want to do something special when 404s occur.

How do I know when a 404 occurs when using a URLConnection ?

Answer 1

first, cast to HttpURLConnection then call connection.connect() instead of getInputStream . Once done, call getResponceCode() . If all is good, then you can get the input stream

Answer 2

If you are ok with a 3rd party library then look at apache commons http client component project. This library has much more user friendly http api than native url connection api in jdk.