What is the proper way of setting headers in a URLConnection?

Question

My code is like the following:

URLConnection cnx = address.openConnection();
cnx.setAllowUserInteraction(false);         
cnx.setDoOutput(true);
cnx.addReque         


        

Answer 1

I'd advise against using low-level constructs such as URLConnection. There are plenty of libraries for sending HTTP requests, with the most prominent being Apache HTTP Client.

Answer 2

The headers must be set prior to getting the InputStream to have any affect - an IllegalStateException will be thrown if the connection is already open.

As far as the User-Agent header specifically, it should be sent if it has been set.

See the URLConnection JavaDoc.

Answer 3

To answer the question, the code is correct. The moment getInputStream(), an HTTP get is sent to the target server.

A side-note on user-agent, if you don't set it, URLConnection will send the default one anyway, which is:

User-Agent: Java/1.6.0_24 (varies depending on your java version)