Updating war files

Suppose you want to replace or add an image file to a deployable .war for customization purposes? What do you do? Simplified procedure below.


Unpacking and making changes to .war files can be a messy business. To reduce that messiness to a degree the first thing I do is make an important change to the procedures you’ll see across the Internet: I do the work on Linux instead of Windows.

The second thing is I don’t use 7-zip, WinZip or even plain vanilla zip to unpack and repack. I use good old jar.

The third thing I do is use jar’s update option rather than re-packing the entire file. Yes, it’s a bit slower and more tedious, but it has the advantage of being much more surgical and thus less risky.

An example:

MyLogo.gif needs to be added to the openam.war so it can be accessed by some custom code.

[webapp@test ~]$ mkdir /data/staging
[webapp@test ~]$ cp /data/install/openam/openam.war /data/staging
[webapp@test ~]$ cd /data/staging
[webapp@test staging]$ jar xf openam.war
[webapp@test staging]$ cp /data/projects/images/MyLogo.gif images/
[webapp@test staging]$ jar uf openam.war images/MyLogo.gif