wood burning stoves 2.0*
The moose likes Sockets and Internet Protocols and the fly likes httpURLConnection content-length always 0 Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login

Win a copy of Android Security Essentials Live Lessons this week in the Android forum!
JavaRanch » Java Forums » Java » Sockets and Internet Protocols
Bookmark "httpURLConnection content-length always 0" Watch "httpURLConnection content-length always 0" New topic

httpURLConnection content-length always 0

Jeff Gaer
Ranch Hand

Joined: Jun 04, 2001
Posts: 99
I know I am missing something obvious, but creating a connection with the following code on java 1.4.2 the content length is always 0 even though it is explicitly set.

URL url = new URL("http://localhost:" + port);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
String testData="this is a test!";
String LEN_HDR="Content-Length";
String TYPE_HDR="Content-Type";


OutputStream os = conn.getOutputStream();
PrintStream ps = new java.io.PrintStream(os);

here are the headers are received on the server

Content-Type: text/html
Content-Length: 0
TESTContent-Length: 15
User-Agent: Java/1.4.2
Host: localhost:91
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive

Thanks in advance for any help


Sun Certified Java Programmer Java 2<P>Jeff Gaer
Jacob Anawalt
Ranch Hand

Joined: Oct 27, 2010
Posts: 32

I was experiencing the same Content-Length: 0 issue with a different Java versions and for seemingly different reasons, or Jeff's code example is not complete.

I tried bumbling through setting up some code to POST to a server using URL and HttpURLConnection and every time the server would not only show Content-Length 0, but the data I was trying to write was also missing as proved by wireshark captures so the Content-Length value of 0 was correct.

Searching around I first got worried that I was experiencing bug id 6997628, "HttpURLConnection strips Content-Length header on Post". I tried different Java 1.6 versions and different JRE's on different OS's. Then I found the tutorial for reading from and writing to an HttpURLConnection [0] and that worked. It didn't make sense. My code said I was writing, but as far as I could tell I was not.

[0] http://download.oracle.com/javase/tutorial/networking/urls/readingWriting.html

Finally I found the difference between the example code and mine. I will re-write the example code with my "mistake" in it:

Moving the write statements to after the getInputStream call seems to ignore them, probably because getInputStream calls connect() and sends the request so that it can have something to read. I don't know how I was suppose to figure this out other than .

I tried reproducing Jeff Gaer's issue, but his code snippet didn't send anything, not even the URL, until I added the getInputStream call (connect() alone didn't do the trick.) Once I did, it would set the correct Content-Length. It continued to work even after commenting out all the setRequestProperty calls and the setRequstMethod call. (Note that those calls are missing from the example.) I was expecting to see an issue with the claimed content-length not matching the written amount ("test" vs "this is a test!" and the extra linefeed) but it worked anyway. I didn't try this on Java 1.4, nor do I care to dig that up to try.

jQuery in Action, 2nd edition
subject: httpURLConnection content-length always 0
Similar Threads
How to submit POST request without an input variable
Java Http Server and Java Http Client
sending image to server using HTTP connection
HTTP request stream created by HttpURLConnection