Using the Axis utilities
Axis also comes with a set of very useful stand alone Java utilities. Since
they are not run from the server you must be careful to set up the proper
classpath before executing them. On my Win98 computer I’ve found it useful to
write a small bat-file that does this for you:
@echo off
set AXISROOT=d:\apache\jakarta-tomcat-4.0.1\webapps\axis\web-inf\lib\
set TOMCATROOT=d:\apache\jakarta-tomcat-4.0.1\
set CP=.
set CP=%CP%;%AXISROOT%axis.jar
set CP=%CP%;%AXISROOT%axis-ant.jar
set CP=%CP%;%AXISROOT%commons-discovery.jar
set CP=%CP%;%AXISROOT%commons-logging.jar
set CP=%CP%;%AXISROOT%jaxrpc.jar
set CP=%CP%;%AXISROOT%log4j-1.2.4.jar
set CP=%CP%;%AXISROOT%saaj.jar
set CP=%CP%;%AXISROOT%wsdl4j.jar
set CP=%CP%;%TOMCATROOT%common\lib\servlet.jar
rem Remove the next if jdk1.4 is used
set CP=%CP%;%TOMCATROOT%common\lib\xerces.jar
set CLASSPATH=%CP% |
Figure 1: The setcp bat file
The first line shows the directory where my Axis jar files are located. The
next line is where Tomcat is installed. To ease debugging of my bat-file I add
one jar file per line. I’ve included all the jar-files from the Axis
installation, and also the servlet jar, which you may find in the Tomcat
common/lib directory. You also need an XML parser if you’re running a JDK prior
to 1.4.
You of course have the option to add the jar files to your global classpath,
but I personally prefer to start out with a clean classpath whenever I run a
Java program.
We’ll need three of the Axis utilities when we build and test the
application:
The AdminClient utility
This utility is used to deploy, undeploy
and list your web services. Again we make a small bat-file for easy
execution:
java org.apache.axis.client.AdminClient %1 |
Figure 2: The adminclient bat file
The tcpmon utility
This utility is used to monitor the HTTP
communication between the client and the server
java org.apache.axis.utils.tcpmon %1 %2 %3 |
Figure 3: The tcpmon bat file
I’ve found it most convenient to place these files in the WEB-INF folder,
together with the deployment files.
When we begin building our application we’ll start using these utilities.
The DVD application
Once more I’ll take out my good old DVD application, which I recently used in
two articles entitled "Struts meets Swing
(1)" and "Struts meets Swing
(2)". The business case is to make an application that can be used to
maintain a collection of DVDs. You should be able to list all DVDs, update and
delete a DVD, create a new DVD, and of course save the collection on persistent
storage (implemented through an XML file). The Swing look is this:
To make a new application based on web service technology (and with exactly
the same GUI) we’ll need the following web services:
- return list of DVD titles (to populate the combo box)
- return details for one DVD (to fill the 4 text fields)
- update a DVD
- create a DVD
- delete a DVD
- save all the DVDs
We’d of course like to use as much of the code from the Struts application as
possible, so let me sketch the architecture of the application:
The DVDManager
is a Java class that handles all the operations on the DVD collection. It
implements the following main actions:
- read (and keep) DVD data from XML file
- return titles for DVDs
- return details for one DVD
- update a DVD
- create a DVD
- delete a DVD
- save all DVDs
It’s therefore easy to match the web service requests to the actions in the
DVDManager.
The DVDManager acts as a buffer to the XML file, and it keeps all the
DVD information in memory and only saves it to the XML file when the user
requests so. The architecture is therefore "single-user", but could easily be
changed to a "multi-user" architecture working on a data base instead. Since the
focus in this article is on web service technology we can live with this
simplified back-end architecture.
The Swing client only holds the titles of the DVDs, and to simplify the
example they’re held in a list structure matching the one in the
DVDManager. This means that element number 3 in one list is also number 3
in the other list. A more realistic solution would probably be to use a unique
key for every DVD for lookup in the DVDManager.
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