Tutorials : Using Apache Axis version 1 to build Web Services :

Looking at the wire

The tcpmon utility is used to look at the HTTP communication between the Axis client and server. In my first article about Axis I showed how it was used, and how it worked. In order to use it you’ll have to direct your requests from your client to another port, for example 8081. You then tell tcpmon to listen to port 8081. It shows what comes in, and then redirects to the Axis port, which is 8080 in a default Tomcat setup. We’ve already made a bat-file for running tcpmon, so we simply issue:

  tcpmon 8081 localhost 8080

Here’s part of what you see when a request for the DVD titles come in (click on the picture to see the whole screen):

A hint on restarting Axis

If you, for some reason, want to restart Axis you don’t have to restart Tomcat. Here’s what you must do:

• in Tomcat’s conf/tomcat-users.xml file add a line like this:
  <user name="java" password="axis" roles="manager" />
• enter this URL in your browser:
  http://localhost:8080/manager/reload?path=/axis
  When you’re prompted for username and password then enter the values from the users-file.

Where to go from here

In my next article I’ll look into some of the Axis features we haven’t covered yet:

• the SoapMonitor, which resembles tcpmon but is sitting on the server side
• the automatic code generation tools. They can take your service class (in our case the DVDService class) and generate both client and server code for you.
• session management, a feature we know from servlets

We’ll also look more into error handling and "Interoperability", which has to do with what we must consider if different platforms and SOAP implementations should be able to talk to each other.

Finally we’ll modify the Struts DVD browser application to use web services.

Installation of the examples

In the resources section below you’ll find a link where you can download a zip file with all the programs and files shown in this article. Here are some tips on how to install the DVD web service:

All files, except the dvds.xml file, must be placed in Tomcat’s webapps/axis directory.

The DVDManager class uses the JDOM package. You must therefore have downloaded JDOM and placed the jdom.jar file in Tomcat’s common/lib directory. The setcp.bat file contains the location of the jdom.jar file.

All examples have been developed using JDK 1.4, and please note, that the DVDClient uses features from this JDK, which are not present in prior versions of the JDK.

Resources

• A zip file with all the code and files from the article
• Home of Axis at xml.apache.org
• Axis Installation Guide
• "Axis: the New Incarnation of Apache SOAP" by Laurent Dananot. A brilliant 45 page introduction to Axis.
• "Axis – an open source web service toolkit for Java" by Mark Volkmann. Pdf-file, 52 pages. Also very good reading.
• The Axis Newsgroups – lots of questions and answers
• jdom.org--the Home of JDOM
• My previous articles from JavaBoutique about Axis and Struts:
  - "Web Services with Axis"
  - "Stepping through Jakarta Struts"
  - "Coding your second Jakarta Struts Application"
  - "Introducing: the Struts bean and logic Tag Libraries"
  - "Struts meets Swing (1)"
  - "Struts meets Swing (2)"

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