JAR - extracting specific files

Question

I have .class and .java files in JAR archive. Is there any way to extract only .java files from it? I've tried this command but it doesn't work:

jar xf jar-file.jar *.java

Solution 1

You can use the unzip command which accepts wildcards in its arguments (which is not the case of the jar command). Something like this should do the trick ( disclaimer : not tested)

unzip youFile.jar "*.java"

Solution 2

From the source:

To extract only certain files from a jar file, supply their filenames:

C:\Java> jar xf myFile.jar foo bar

Using wildcards is a shell thing, and you should not expect it to work when extracting from a JAR file (which, as you've realized, is the case).

What you can do, is supply a list of the files you want to extract, via the @ modifier:

jar xf my.jar @myfiles.lst

where myfiles.lst would be:

com/my/MyClass.java
com/my/MySecondClass.java

This file could easily be created automatically with creative use of jar tvf, awk and your desired extraction pattern. I'll leave that as an exercise and/or another SO question :-)

Or you could use unzip - a JAR file is basically a zip-file.

Cheers,