- java.util.zip Package Classes
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- java.util.zip - GZIPInputStream
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- java.util.zip - ZipFile
- java.util.zip - ZipInputStream
- java.util.zip - ZipOutputStream
- java.util.zip Package Extras
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- java.util.zip - Error
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java.util.zip.GZIPInputStream.read() Method Example
Description
The java.util.zip.GZIPInputStream.read(byte[] buf, int off, int len) method 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.
Declaration
Following is the declaration for java.util.zip.GZIPInputStream.read(byte[] buf, int off, int len) method.
public int read(byte[] buf, int off, int len) throws IOException
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 stream is reached.
Exceptions
NullPointerException − If buf is null.
IndexOutOfBoundsException − If off is negative, len is negative, or len is greater than buf.length - off.
ZipException − if the compressed input data is corrupt.
IOException − if an I/O error has occurred.
Example
The following example shows the usage of java.util.zip.GZIPInputStream.read(byte[] buf, int off, int len) method.
package com.tutorialspoint; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.Arrays; import java.util.zip.DataFormatException; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class GZIPInputStreamDemo { public static void main(String[] args) throws DataFormatException, IOException { String message = "Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;" +"Welcome to TutorialsPoint.com;"; System.out.println("Original Message length : " + message.length()); byte[] input = message.getBytes("UTF-8"); // Compress the bytes ByteArrayOutputStream arrayOutputStream = new ByteArrayOutputStream(); GZIPOutputStream outputStream = new GZIPOutputStream(arrayOutputStream); outputStream.write(input); outputStream.close(); //Read and decompress the data byte[] readBuffer = new byte[5000]; ByteArrayInputStream arrayInputStream = new ByteArrayInputStream(arrayOutputStream.toByteArray()); GZIPInputStream inputStream = new GZIPInputStream(arrayInputStream); int read = inputStream.read(readBuffer,0,readBuffer.length); inputStream.close(); //Should hold the original (reconstructed) data byte[] result = Arrays.copyOf(readBuffer, read); // Decode the bytes into a String message = new String(result, "UTF-8"); System.out.println("UnCompressed Message length : " + message.length()); } }
Let us compile and run the above program, this will produce the following result −
Original Message length : 300 UnCompressed Message length : 300Print