Reading a text file from a jar file?

[arun mahajan]

Hello Everybody,
Ok I think it is now the appropriate time to ask this questions after all my trials.
I have a jar file which has following types of files:
File name Directory Structure
test.class /
makePanel.class /test
pic1.gif /images/pic
pic2 /images
abc.ict /
xyz.id /images/pic
where xyz.id and abc.ict are simple text files with a change in extension. Now problem is in extracting it... As the documentation goes that I have to use ClassLoader to load same before using.. I tried the following:
For Images:

1. cl = ResourceAnchor.class.getClassLoader();
 Image img = Toolkit.getDefaultToolkit().getImage(cl.getResource("images/pic2.gif"));

It works.
2. Now problem comes in when I want to read all the files from the directory /image/pic.. In a normal case I was trying the following code snippet...

String path = "images/logo";
File f = new File(path);
FilenameFilter only = new FileCheck();
File[] s1 = f.listFiles();
System.out.println("s1: "+s1.length);

but failed to retrieve same from jar file with the above concept.
if i tried with:

ClassLoader cl = this.getClass().getClassLoader();
File f = new File(c1.getResource(path).getFile());

It doesn't work...perhaps the path it is giving is:
jar:file:/E:/test/test.jar!/images/pic
Can somebody help me in this regard...

regards,
arun

[arun mahajan]

In a desperate attemp I tried with another set of codes:

String path = "/images/pic";
ClassLoader cl = this.getClass().getClassLoader();
URL ur = c1.getResource(path);
String x = ur.getFile();
InputStream in = c1.getResourceAsStream("images/logo");
System.out.println("c1: "+c1);
System.out.println("ur: "+ur);
System.out.println("x: "+x);
System.out.println("in: "+in);

Here in above the InputStream object in is null...while all other has some value..
I think I am somewhere missing the concept badly of jar files..can somebody help me...
regards,
arun

[Thomas Paul]

Why can't you use JarInputStream?

[arun mahajan]

Thanks Thomas for your answer and I tried with following code but again in vain...again NullPointerException...Any more idea?

JarInputStream jis = new JarInputStream(new FileInputStream("insta.jar"));
String fname = "";
while (true)
{
ZipEntry ze = jis.getNextEntry();
if (ze==null) break;
System.out.println("++++++++++++: "+ze.getName());
fname = ze.getName();
}
File f = new File(fname);

regards,
Arun

[Thomas Paul]

How about showing the actual error? Where are you getting the NullPointerException?

[arun mahajan]

Oops I got yhe answer for it at last..Special thanks to Thomas who has given me a lead..
posting the code snippet if some one is interested !!

String fanme = "abc.txt";
JarFile jf = new JarFile("test.jar");
InputStream is = jf.getInputStream(jf.getEntry(fname));
ObjectInputStream ois = new ObjectInputStream (is);

regards,
Arun

[Dirk Schreckmann]

Well done, Arun, and thanks for sharing what you learned.