Java GZIP
Here is a simple java GZIP example program showing how can we compress a file to GZIP format and then decompress the GZIP file to create a new file.
GZIPExample.java
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package com.journaldev.files; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.zip.GZIPInputStream; import java.util.zip.GZIPOutputStream; public class GZIPExample { public static void main(String[] args) { String file = "/Users/pankaj/sitemap.xml"; String gzipFile = "/Users/pankaj/sitemap.xml.gz"; String newFile = "/Users/pankaj/new_sitemap.xml"; compressGzipFile(file, gzipFile); decompressGzipFile(gzipFile, newFile); } private static void decompressGzipFile(String gzipFile, String newFile) { try { FileInputStream fis = new FileInputStream(gzipFile); GZIPInputStream gis = new GZIPInputStream(fis); FileOutputStream fos = new FileOutputStream(newFile); byte[] buffer = new byte[1024]; int len; while((len = gis.read(buffer)) != -1){ fos.write(buffer, 0, len); } //close resources fos.close(); gis.close(); } catch (IOException e) { e.printStackTrace(); } } private static void compressGzipFile(String file, String gzipFile) { try { FileInputStream fis = new FileInputStream(file); FileOutputStream fos = new FileOutputStream(gzipFile); GZIPOutputStream gzipOS = new GZIPOutputStream(fos); byte[] buffer = new byte[1024]; int len; while((len=fis.read(buffer)) != -1){ gzipOS.write(buffer, 0, len); } //close resources gzipOS.close(); fos.close(); fis.close(); } catch (IOException e) { e.printStackTrace(); } } } |
While decompressing a GZIP file, if it’s not in GZIP format, following exception will be thrown.
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java.util.zip.ZipException: Not in GZIP format at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:164) at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:78) at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:90) at com.journaldev.files.GZIPExample.decompressGzipFile(GZIPExample.java:25) at com.journaldev.files.GZIPExample.main(GZIPExample.java:18) |
That’s all for Java GZIP Example.