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.addRequestProperty("User-Agent", 
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)");
InputStream is = cnx.getInputStream();

Is it ok if I set the headers before I get the InputStream? Will my header be sent, or will the server see the default URLConnection's user-agent ( if any ) ?

score 21 · Accepted Answer · edited Sep 13 '12 at 08:51

21

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.

edited Sep 13 '12 at 08:51

lowky12

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answered Dec 01 '08 at 17:51

Ken Gentle

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score 4 · Answer 2 · edited Aug 05 '11 at 21:51

4

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)

edited Aug 05 '11 at 21:51

Bo Persson

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answered Aug 05 '11 at 12:55

Leif Ashley

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score -2 · Answer 3 · answered Sep 13 '12 at 09:01

-2

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.

answered Sep 13 '12 at 09:01

NewlessClubie

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(should be comment, does not answer question) – BadZen Apr 07 '15 at 17:00
Apache HTTP Client is discouraged and deprecated in the Android Framework. Google encourages the use of HttpURLConnection. – afollestad Jul 13 '15 at 19:34

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

3 Answers3

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