Java Reference
In-Depth Information
META-INF
MANIFEST.MF
typical-war_1.0.0.jar
WEB-INF
web.xml
Classes
Figure 11.5
A typical WAR layout
more easily understandable for
WAR
developers, and, most critically, it allows the
WAR
to continue being used as a
WAR
and as a
WAB
!
Changing the default internal classpath of an
OSG
i bundle can be easily achieved
using the
Bundle-ClassPath
header. This takes a comma-separated list of classpath
locations, which can either be folders or
JAR
files, that are specified relative to the root
of the bundle. If you were trying to make the
WAR
from figure 11.5 work in
OSG
i, then
you would need to set the classpath as follows:
Bundle-ClassPath: WEB-INF/classes, WEB-INF/lib/myLib.jar,
WEB-INF/lib/secondLib.jar
When your
WAR
has correctly specified its internal
OSG
i classpath, then you're much
closer to being able to get it running. In the majority of cases, you still won't be able to
load any of your classes. The internal classpath of a bundle is only a small part of the story.
FINISHING OFF YOUR OSGI METADATA
The key piece of information missing from your
WAR
is the most fundamental part of
making your
WAR
into an
OSG
i bundle; it's the modularity statement, the set of pack-
ages that you want to import. Some of the packages that need to be imported are obvi-
ous; for example, we would wager that your
WAR
needs to import
javax.servlet
and
javax.servlet.http
.
Supported versions
Over the life of the Java EE specifications, there have been a number of versions of
the Servlet Specification. The OSGi Web Applications Specification defines support
for version 2.5 of the Servlet Specification. As a result, you shouldn't rely on being
able to migrate Servlet 3.0 applications to an arbitrary OSGi web container. On the
other hand, the OSGi Web Applications Specification does allow for implementations
to support Servlet 3.0 applications. If you do need to use Servlet 3.0 in your applica-
tion, then make sure that your container supports it, and also remember that the cor-
rect semantic version for the Servlet 3.0 package is
2.6
.
