Question

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);
    }
}

Answer 1

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