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

问题:

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?

回答1:

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.

回答2:

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

回答3:

Just rename the .war into .jar and unzip it using Winrar (or any other archive manager).

回答4:

If you using Linux or Ubuntu than you can directly extract data from .war file.

A war file is just a jar file, to extract it, just issue following command using the jar program:

jar -xvf yourWARfileName.war

回答5:

Like you said, a jar is a zip file (not a special type, but just a plain old zip), so either library could be made to work. The reasoning is that the average person, seeing a *.zip extension, tends to unzip it. Since the app server wants it unzipped, a simple rename keeps people from unzipping it simply out of habit. Likewise, *.war file also should remain uncompressed.

java.util.jar basically just adds additional functionality to java.util.zip with very little extra overhead. Let the java.util.jar be a helper in posting, etc... and use it.

回答6:

Jar class/package is for specific Jar file mechanisms where there is a manifest that is used by the Jar files in some cases.

The Zip file class/package handles any compressed files that include Jar files, which is a type of compressed file.

The Jar classes thus extend the Zip package classes.

回答7:

You can use a turn-around and just deploy the application into tomcat server: just copy/paste under the webapps folder. Once tomcat is started, it will create a folder with the app name and you can access the contents directly