In this post we'll see how to use GZIP to compress and decompress a file in Java. You will mainly use GZIP tool to compress and decompress files in Unix systems. Here note that you can only compress a single file using GZIP not multiple files residing in a folder.
Refer Creating Tar File And GZipping Multiple Files - Java Program to see how to gzip multiple files in Java.
Steps to gzip a file
In order to compress a file using GZIP in Java the steps are as follows-
- For reading the source file (file which has to be GZIPped) create a FileInputStream.
- Create a FileOutputStream to the target file (output GZIPped file).
- Create a GZIPOutputStream wrapping the FileOutputStream.
- Then you just need to read from the input stream and write to the output stream.
Steps to decompress a file
In order to decompress a file using GZIP in Java the steps are as follows-
- For reading the compressed file create a FileInputStream.
- Wrap that FileInputStream with in a GZIPInputStream.
- Create a FileOutputStream to the new file (created on decompressing GZIP file).
- Then you just need to read from the input stream and write to the output stream.
Java example for compressing and decompressing file in GZIP format
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
public class GZipDemo {
public static void main(String[] args) {
// Path to file which is gzipped
String SOURCE_FILE = "G:\\Test\\abc.txt";
// Path to gzipped output files
String GZIP_OUTPUT_FILE = "G:\\Test\\abc.gz";
// File you get after decompressings
String GZIP_NEW_FILE = "G:\\Test\\newabc.txt";
GZipDemo gZipDemo = new GZipDemo();
try {
// Compressing a file
gZipDemo.compressGZipFile(SOURCE_FILE, GZIP_OUTPUT_FILE);
// decompressing a file
gZipDemo.deCompressGZipFile(GZIP_OUTPUT_FILE, GZIP_NEW_FILE);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* Method to gzip a file
* @param sourceFile
* @param outputFile
* @throws IOException
*/
public void compressGZipFile(String sourceFile, String outputFile)
throws IOException{
FileInputStream fis = new FileInputStream(sourceFile);
FileOutputStream fos = new FileOutputStream(outputFile);
GZIPOutputStream gZIPOutputStream = new GZIPOutputStream(fos);
byte[] buffer = new byte[1024];
int len;
while((len = fis.read(buffer)) > 0){
gZIPOutputStream.write(buffer, 0, len);
}
// Keep it in finally
fis.close();
gZIPOutputStream.close();
}
/**
* Method to decompress a gzip file
* @param gZippedFile
* @param newFile
* @throws IOException
*/
public void deCompressGZipFile(String gZippedFile, String newFile)
throws IOException{
FileInputStream fis = new FileInputStream(gZippedFile);
GZIPInputStream gZIPInputStream = new GZIPInputStream(fis);
FileOutputStream fos = new FileOutputStream(newFile);
byte[] buffer = new byte[1024];
int len;
while((len = gZIPInputStream.read(buffer)) > 0){
fos.write(buffer, 0, len);
}
// Keep it in finally
fos.close();
gZIPInputStream.close();
}
}
That's all for this topic Compress And Decompress File Using GZIP Format in Java. If you have any doubt or any suggestions to make please drop a comment. Thanks!
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