Java.util.zip.GZIPInputStream class in Java

This class implements a stream filter for reading compressed data in the GZIP file format.

Constructors

• GZIPInputStream(InputStream in) : Creates a new input stream with a default buffer size.
• GZIPInputStream(InputStream in, int size) : Creates a new input stream with the specified buffer size.

Methods :

• void close() : Closes this input stream and releases any system resources associated with the stream.

  Syntax :public void close()
             throws IOException
  Specified by:
  close in interface Closeable
  Specified by:
  close in interface AutoCloseable
  Overrides:
  close in class InflaterInputStream
  Throws:
  IOException 

• int read(byte[] buf, int off, int len) : Reads uncompressed data into an array of bytes. If len is not zero, the method will block until some input can be decompressed; otherwise, no bytes are read and 0 is returned.

  Syntax :public int read(byte[] buf,
         int off,
         int len)
           throws IOException
  Overrides:
  read in class InflaterInputStream
  Parameters:
  buf - the buffer into which the data is read
  off - the start offset in the destination array b
  len - the maximum number of bytes read
  Returns:
  the actual number of bytes read, or -1 if the end of the
  compressed input stream is reached
  Throws:
  NullPointerException
  IndexOutOfBoundsException
  ZipException
  IOException 

Methods inherited from class java.util.zip.InflaterInputStream
available, fill, mark, markSupported, read, reset, skip
Methods inherited from class java.io.FilterInputStream
read
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Program :

//Java program demonstrating GZipInputStream methods

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.zip.GZIPInputStream;

class GZipInputStreamDemo
{
    public static void main(String[] args) throws IOException
    {
        FileInputStream fis = new FileInputStream("file.txt");
        GZIPInputStream gzis = new GZIPInputStream(fis);

        //Uncompressed FileContents
        //01234567890
        byte b[]=new byte[10];

        //skipping 1 byte
        gzis.skip(1);

        //illustrating available() and
        //read(byte b[],int off,int len)
        if( gzis.available()!=-1)
            gzis.read(b);
        System.out.println(Arrays.toString(b));

        //closing the stream
        gzis.close();
    }
}

Output :

[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

This article is contributed by Nishant Sharma. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.