Manipulating Zip files in Java, compressing/decompressing

Compression can be reproduced at will, but please specify the source and author


Sonymusic


2003.05.28


==========================================================================


operation of Zip files in Java, compression/decompression








package test.nothing;





import java.io.*;


import java.util.*;


import java.util.zip.*;





import com.beaconsystem.util.*;





import junit.framework.TestCase;





/**


* @author Sonymusic


*


* is used to test Java.util.zip package compression and decompression file Zip file example.


* is written based on JUnit, includes two test methods, and three helper methods.


* Note that the operation during the use of all the flow, so not only can read and write files. This is just a simple example.


*/


public class Testzipop extends TestCase {





/**


* constructor for Testzipop.


* @param arg0


*/


public Testzipop (String arg0) {


super (ARG0);


}





public static void Main (string[] args) {


Junit.textui.TestRunner.run (Testzipop.class);


}





/**


* Zip compression function test.


* Compresses all files in the D:\\temp\\zipout directory along with subdirectories to D:\\temp\\out.zip.


* @throws Exception


*/


public void Testcreatezip () throws exception{


//Compress all files under Basedir, including subdirectories


String basedir= "D:\\temp\\zipout";


List filelist=getsubfiles (New File (BaseDir));





//Compressed filename


zipoutputstream zos=new Zipoutputstream (New FileOutputStream ("D:\\temp\\out.zip"));





ZipEntry Ze=null;


byte[] Buf=new byte[1024];


int readlen=0;


for (int i = 0; I <filelist.size (); i++) {


file f= (file) filelist.get (i);


System.out.print ("adding:" +f.getpath () +f.getname ());





Create a zipentry and set the name and some other properties


ze=new ZipEntry (Getabsfilename (BaseDir, f));


ze.setsize (F.length ());


Ze.settime (F.lastmodified ());





//Add ZipEntry to Zos and write the actual file contents


zos.putnextentry (ze);


InputStream is=new Bufferedinputstream (new FileInputStream (f));


while ((Readlen=is.read (buf, 0, 1024))!=-1) {


zos.write (buf, 0, Readlen);


}


Is.close ();


System.out.println ("Done ...");


}


Zos.close ();


}





/**


* Test the decompression function.


* Extract the D:\\download\\test.zip file into the D:\\temp\\zipout directory.


* @throws Exception


*/


public void Testreadzip () throws exception{


//inputstream is=new Bufferedinputstream (New FileInputStream ());


String basedir= "D:\\temp\\zipout";


ZipFile zfile=new zipfile ("D:\\download\\test.zip");


System.out.println (Zfile.getname ());


enumeration zlist=zfile.entries ();


ZipEntry Ze=null;


byte[] Buf=new byte[1024];


while (zlist.hasmoreelements ()) {


//From ZipFile to get a zipentry


ze= (ZipEntry) zlist.nextelement ();


if (ze.isdirectory ()) {


System.out.println ("Dir:" +ze.getname () + "skipped ...");


continue;


}


System.out.println ("Extracting:" +ze.getname () + "T" +ze.getsize () + "T" +ze.getcompressedsize ());





//To ZipEntry as a parameter to get a inputstream, and write to OutputStream


outputstream os=new Bufferedoutputstream (New FileOutputStream (Getrealfilename, BaseDir ()));


inputstream is=new bufferedinputstream (zfile.getinputstream (Ze));


int readlen=0;


while ((Readlen=is.read (buf, 0, 1024))!=-1) {


Os.write (buf, 0, Readlen);


}


Is.close ();


Os.close ();


System.out.println ("Extracted:" +ze.getname ());


}


Zfile.close ();


}





/**


* Given the root directory, returns the actual file name corresponding to a relative path.


* @param baseDir Specifies the root directory


* @param absfilename relative pathname from the name
in ZipEntry

* @return Java.io.File the actual file


*/


Private File Getrealfilename (string baseDir, String absfilename) {


string[] Dirs=regex.split ("/", absfilename);


//system.out.println (dirs.length);


file Ret=new file (BaseDir);


if (dirs.length>1) {


for (int i = 0; I <dirs.length-1; i++) {


ret=new File (ret, dirs[i]);


}


}


if (!ret.exists ()) {


Ret.mkdirs ();


}


ret=new File (ret, dirs[dirs.length-1]);


return ret;


}





/**


* Given the root directory, returns the relative path of another file name for the path in the zip file.


* @param baseDir java.lang.String root directory


* @param realfilename java.io.File the actual filename


* @return Relative filename


*/


private String Getabsfilename (String baseDir, File realfilename) {


File Real=realfilename;


file Base=new file (BaseDir);


String ret=real.getname ();


while (true) {


Real=real.getparentfile ();


if (real==null) break;


if (real.equals (base)) break;


else{


ret=real.getname () + "/" +ret;


}


}


return ret;


}





/**


* Gets a list of all the files in the specified directory, including subdirectories.


* @param the directory specified by BaseDir File


* @return contains the Java.io.File list


*/


Private List Getsubfiles (File baseDir) {


List ret=new ArrayList ();


//file base=new File (BaseDir);


file[] Tmp=basedir.listfiles ();


for (int i = 0; I <tmp.length; i++) {


if (Tmp[i].isfile ()) {


Ret.add (Tmp[i]);


}


if (tmp[i].isdirectory ()) {


Ret.addall (Getsubfiles (tmp[i));


}


}


return ret;


}





}