Java zip/gzip file compression and decompression __java

Java IO

In order to reduce the amount of data transmitted in Java, a special compression stream is provided to compress a file or folder into a Zip,gzip,jar file format. Compression Stream Implementation

Three compressed formats supported by Java: Zip, jar, gzip.

1.zip is a more common compression format, Java provides a java.util.zip package, common classes: Zipinputstream zipoutputstream zipentry ZipFile

Rely on the above 4 classes to complete the zip type file operation.

2.Jar is a Java-proprietary compression format, Java provides a Java.util.jar package, common classes: Jarinputstream jaroutputstream jarentry Jarfile

3.GZIP is a file compression format for UNIX systems, and the frequently used. gz file in Linux systems is the gzip format, and Java provides gzipinputstream Gzipoutputstream

This paper takes zip compression/decompression as an example to explain. Compress

@Test public
void Testzip () throws IOException {file

    zipfile = new File ("D:\\log.zip");//Compressed Files
    Zipoutputstream zipout = null;
    try{
        zipout = new Zipoutputstream (new FileOutputStream (ZipFile));
        File dir = new file ("d:\\logs\\info\\");   Folders to be compressed
        file[] files = dir.listfiles ();
        for (File file:files) {
            inputstream in = null;
            try{
                zipout.putnextentry (New ZipEntry (File.getname ()));
                Zipout.setcomment ("Test zip");  Set Note
                in = new FileInputStream (file);//define Input stream
                ioutils.copy (in, zipout);
            } finally {
                ioutils.closequietly (in);}}}
    finally {
        ioutils.closequietly (zipout);
    }

    SYSTEM.OUT.PRINTLN ("Compressed file Complete");
}

Decompression

@Test public void Testunzip () throws IOException {file dir = new file ("D:\\test");
    if (!dir.exists ()) {dir.mkdirs ();
    The file Srcfile = new file ("D:\\log.zip");

    ZipFile zipfile = new ZipFile (srcfile);
    Zipinputstream zipin = null;
        try{Zipin = new Zipinputstream (new FileInputStream (srcfile));
        ZipEntry entry = null;
            while ((entry = Zipin.getnextentry ())!=null) {System.out.println ("Extract file:" + entry.getname ());
            OutputStream out = null;
            InputStream in = null;
                try{File File = new file (dir, Entry.getname ());
                in = Zipfile.getinputstream (entry);
                out = new FileOutputStream (file);
            Ioutils.copy (in, out);
                }finally {ioutils.closequietly (out);
            Ioutils.closequietly (in);
    }}}finally {ioutils.closequietly (zipin);
} System.out.println ("Extract file Complete"); }

Ioutils.java

Import java.io.Closeable;
Import java.io.IOException;
Import Java.io.InputStream;

Import Java.io.OutputStream; /** * ${description} * * @author Ricky Fung * @create 2016-10-31 10:19 * * public class Ioutils {public static V
    OID closequietly (InputStream input) {closequietly (closeable) input);
    public static void closequietly (OutputStream output) {closequietly (closeable) output);
                public static void closequietly (Closeable closeable) {try {if (closeable!= null) {
            Closeable.close ();
        } catch (IOException e) {e.printstacktrace ();
            } public static void Closequietly (Closeable ... closeables) {for (closeable closeable:closeables) {
        closequietly (closeable);  public static long copy (InputStream in, outputstream out, int buffersize) throws IOException {byte[]
        Buff = new Byte[buffersize]; return copy (in, out, buff); public static long copy (InputStream in, outputstream out) throws IOException {byte[] buff = new byte[1024]
        ;
    return copy (in, out, buff); 
        public static long copy (InputStream in, outputstream out, byte[] buff) throws IOException {Long Count = 0;
        int len =-1;
            while ((Len=in.read (buff, 0, buff.length))!=-1) {out.write (buff, 0, Len);
        Count = Len;
    return count; }
}