Why the zip file downloaded is corrupted?

[Quan Qiu <qu...@gmail.com>]

Hello all

I used HttpClinet (the get method) to download a zip file from the Tomcat
server. All works fine, expect the zip file downloaded is corrupted. Yes I
can extract the content by using command "unzip", but I got the error of
"file #1:  bad zipfile offset (local header sig):  0"

>unzip out.zip
Archive:  out.zip
file #1:  bad zipfile offset (local header sig):  0
replace gs2mgppdemo/etc/collectionConfig.xml? [y]es, [n]o, [A]ll, [N]one,
[r]ename: A
  inflating: gs2mgppdemo/etc/collectionConfig.xml
  inflating: gs2mgppdemo/metadata/dls.mds
  inflating: gs2mgppdemo/metadata/ex.mds
  inflating: gs2mgppdemo/metadata/profile.xml
  inflating: infomine/etc/collectionConfig.xml

This error caused failure of unziping the file when using the java code. The
error message is below:

java.lang.InternalError: jzentry == 0,
jzfile = 134895168,
total = 17,
name = /research/qq6/out.zip,
i = 1,
message = invalid LOC header (bad signature)
        at java.util.zip.ZipFile$2.nextElement(ZipFile.java:323)
        at org.greenstone.gatherer.util.UnzipTools.unzipFile(UnzipTools.java
:46)

The size of the zip file downloaded is exactly the same with the original
one though, two files seem different when I run "diff" to compare them.

Does anyone tell me what's going wrong here?

The java code for saving the response stream to a zip file is :
            InputStream in = getMethod.getResponseBodyAsStream();
            byte[] b = new byte[1024];
            int len = in.read(b);
            if (len >= 0) {
                FileOutputStream zip_fos = new
FileOutputStream("/research/qq6/out.zip");
                int offset = 0;
                while (len >=0) {
                      zip_fos.write(b, 0, len);

                      len = in.read(b, offset, 1024);
                      }
              }

The perl script for reading the zip file into STDOUT is :
    $file_path="/research/qq6/qq6-collection-configurations.zip";
    if (open(PIN, "<$file_path")) {
        print STDOUT "Content-Type:application/zip\n\n";
        my $buf;
        my $num_bytes = 0;
        binmode(PIN);
       binmode(STDOUT);
       while (read(PIN, $buf, 1024) > 0) {
          print STDOUT $buf;
         $num_bytes += length($buf);
      }
      close(PIN);
    }

Sorry for my English.