CODEWITHSUNDEEP
javaiogzip
user1777900
user1777900

Reputation: 985

Compressing an input stream Java

This honestly should not be having so many issues, but I must be missing something obvious.

I can compress a file just fine using GZIPOutputStream but when I try to get the input directly (not from a file, but from a pipe or something), when I go to call gunzip -d on my file to see if it decompresses correctly, it tells me that it runs into an end of file immediately. Basically, I want these to work

echo foo | java Jgzip >foo.gz

or

java Jzip <test.txt >test.gz

And there's no guarantee these are strings, so we're reading byte by byte. I thought I could just use System.in and System.out, but that doesn't seem to working.

public static void main (String[] args) {
    try{
        BufferedInputStream bf = new BufferedInputStream(System.in);
        byte[] buff = new byte[1024];
        int bytesRead = 0;

        GZIPOutputStream gout = new GZIPOutputStream (System.out);

        while ((bytesRead = bf.read(buff)) != -1) {
            gout.write(buff,0,bytesRead);
        }
    }
    catch (IOException ioe) {
        System.out.println("IO error.");
        System.exit(-1);    
    }
    catch (Throwable e) {
        System.out.println("Unexpected exception or error.");
        System.exit(-1);
    }
}

Upvotes: 1

Views: 1101

Answers (2)

Aubin
Aubin

Reputation: 14883

I suggest:

OutputStream gout= new GZIPOutputStream( System.out );
System.setOut( new PrintStream( gout ));              //<<<<< EDIT here
while(( bytesRead = bf.read( buff )) != -1 ) {
   gout.write(buff,0,bytesRead);
}
gout.close(); // close flush the last remaining bytes in the buffer stream

Upvotes: 1

Axel
Axel

Reputation: 14169

You forgot to close the stream. Simply add gout.close(); after the while loop to make it work:

axel@loro:~/workspace/Test/bin/tmp$ ls -l
total 12
-rw-rw-r-- 1 axel axel 1328 Oct 27 10:49 JGZip.class
axel@loro:~/workspace/Test/bin/tmp$ echo "hallo" | java JGZip > test.gz
axel@loro:~/workspace/Test/bin/tmp$ ls -l
total 24
-rw-rw-r-- 1 axel axel 1328 Oct 27 10:49 JGZip.class
-rw-rw-r-- 1 axel axel   26 Oct 27 10:49 test.gz
axel@loro:~/workspace/Test/bin/tmp$ gzip -d test.gz 
axel@loro:~/workspace/Test/bin/tmp$ ls -l
total 24
-rw-rw-r-- 1 axel axel 1328 Oct 27 10:49 JGZip.class
-rw-rw-r-- 1 axel axel    6 Oct 27 10:49 test
axel@loro:~/workspace/Test/bin/tmp$ cat test
hallo

Upvotes: 1

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