how to decompress http response ?

Question

Hi Can any one of you solve this problem !

Problem Description:

i have received content-encoding: gzip header from http web-server. now i want to decode the content but when i use GZIP classes from jdk 1.6.12, it gives null.

does it means that contents are not in gzip format ? or are there some another classes for decompress http response content?

Sample Code:

System.out.println("Reading InputStream");
InputStream in = httpuc.getInputStream();// httpuc is an object of httpurlconnection
System.out.println("Before reading GZIP inputstream");
System.out.println(in);
GZIPInputStream gin = new GZIPInputStream(in));
System.out.println("After reading GZIP inputstream");

Output:

Reading InputStream
Before reading GZIP inputstream
sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@8acf6e
null

I have found one error in code, but don't able to understand it properly. what does it indicates.

Error ! java.io.EOFException

Thanks

Answer 1

The expression new GZIPInputStream(in) can never return null - a constructor call can only return a new object or throw an exception.

Could you post a short but complete program to demonstrate the problem? Or at the very least part of your code and why you think something is null?

Answer 2

I think you should have a look at HTTPClient, which will handle a lot of the HTTP issues for you. In particular, it allows access to the response body, which may be gzipped, and then you simply feed that through a GZIPInputStream

e.g.

    Header hce = postMethod.getResponseHeader("Content-Encoding");
    InputStream in = null;
    if(null != hce)
    {
     if(hce.getValue().equals(GZIP)) {
        in = new GZIPInputStream(postMethod.getResponseBodyAsStream());
     }
         // etc...

Answer 3

I second Brian's suggestion. Whenever u need to deal with getting/posting stuff via HTTP don't bother with low-level access use the Apache HTTP client.