How to extract .war files in java? ZIP vs JAR

Question

I have a web program where I want the user to be able to import a .war file and I can extract certain files out of the .war file. I have found two class libraries: java.util.zip.* and java.util.jar.*. From what I understand, a WAR file is a special JAR file which is a special ZIP file. So would it be better to use java.util.jar? If ZIP and JAR files are pretty much the same why is there a need for two different libraries?

Answer 1

WAR file is just a JAR file, to extract it, just issue following jar command –

jar -xvf yourWARfileName.war 

If the jar command is not found, which sometimes happens in the Windows command prompt, then specify full path i.e. in my case it is,

 c:\java\jdk-1.7.0\bin\jar -xvf my-file.war 

Answer 2

If you look at the JarFile API you'll see that it's a subclass of the ZipFile class.

The jar-specific classes mostly just add jar-specific functionality, like direct support for manifest file attributes and so on.

It's OOP "in action"; since jar files are zip files, the jar classes can use zip functionality and provide additional utility.