Zip file is normally used for distributing files and directories. Zip file serves two purposes one is compressing the file and another of creating a achive of multiple files and directories. Now a days with faster internet speed and precompressed files like jpg and mp4 etc. It will be faster to disable compression altogether to speed up the compression. I wrote a simple program in java to create zip file without compression. I was using a mp4 file as content of zip file. With compression enabled it was taking 5 time more time and giving a compression of 5% which is not worth for time spent. Following is the source code:
package zipperformance;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.zip.Deflater;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;
import java.util.zip.CRC32;
public class ZipCreater {
public static void main(String[] args) {
long startTime = System.currentTimeMillis();
zipDirectory("files", "test.zip");
long endTime = System.currentTimeMillis();
System.out.println(endTime-startTime);
}
public static void zipDirectory( String dirPath, String zipFilePath )
{
FileOutputStream fos = null;
try
{
// Create the file output streams for both the file and the zip.
File file = new File( zipFilePath );
if(file.getParentFile()!=null) {
file.getParentFile().mkdirs();
}
fos = new FileOutputStream( zipFilePath );
BufferedOutputStream bos = new BufferedOutputStream(fos);
ZipOutputStream zos = new ZipOutputStream( fos );
zos.setLevel(Deflater.BEST_SPEED);
dirFunc( dirPath, dirPath, zos );
// Close the file output streams for both the file and the zip.
zos.flush();
zos.close();
fos.close();
}
catch ( IOException e )
{
e.printStackTrace();
}
}
private static void dirFunc( String dirName, String baseExportPath, ZipOutputStream zos )
{
try
{
File dirObj = new File( dirName );
if ( dirObj.exists() == true )
{
if ( dirObj.isDirectory() == true )
{
// Create an array of File objects, one for each file or directory in dirObj.
File[] fileList = dirObj.listFiles();
// Loop through File array and display.
for ( int i = 0; i < fileList.length; i++ )
{
if ( fileList[i].isDirectory() )
{
dirFunc( fileList[i].getPath(), baseExportPath, zos );
}
else if ( fileList[i].isFile() )
{
// Call the zipFunc function
zipFunc( fileList[i].getPath(), baseExportPath, zos );
}
}
}
}
}
catch ( Exception e )
{
e.printStackTrace();
}
}
private static void zipFunc( String filePath, String baseExportPath, ZipOutputStream zos )
{
try
{
String absolutePath = filePath;
String prefixFilePath = baseExportPath;
int index = prefixFilePath.length();
filePath = filePath.substring( ++index );
// Create a file input stream and a buffered input stream.
long size = Files.size(Paths.get(absolutePath));
FileInputStream fis = new FileInputStream( absolutePath );
BufferedInputStream bis = new BufferedInputStream( fis );
CRC32 crc32 = new CRC32();
byte[] data = new byte[1024*128];
int byteCount;
// Create a loop that reads from the buffered input stream and writes
// to the zip output stream until the bis has been entirely read.
while ( ( byteCount = bis.read( data, 0, data.length ) ) > -1 )
{
crc32.update( data, 0, byteCount );
}
long crc=crc32.getValue();
// Create a Zip Entry and put it into the archive (no data yet).
ZipEntry fileEntry = new ZipEntry( filePath );
fileEntry.setMethod(ZipEntry.STORED);
fileEntry.setSize(size);
fileEntry.setCrc(crc);
zos.putNextEntry( fileEntry );
bis.close();
fis = new FileInputStream( absolutePath );
bis = new BufferedInputStream( fis );
// Create a loop that reads from the buffered input stream and writes
// to the zip output stream until the bis has been entirely read.
while ( ( byteCount = bis.read( data, 0, data.length ) ) > -1 )
{
zos.write( data, 0, byteCount );
}
}
catch ( IOException e )
{
e.printStackTrace();
}
}
}
