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Getting Started
Because you don't know who will be the client of your Web Service, and due to Axis limitations, you cannot use collection classes, because there is no formal interoperability with other SOAP implementations, and nothing in the SOAP specifications which covers complex objects. The most reliable way to send aggregate objects is to use arrays—this is suggested by official documentation, and advice followed in this article. Also, Axis' documentation says that you cannot send arbitrary Java objects over the wire and expect them to be understood at the far end. Axis will only send objects for which there is a registered Axis serializer. So, you shouldn't send arbitrary objects at all, but in general, BeanSerializer can be used to serialize any class that follows the JavaBean pattern of accessor and mutator.
This stateless session EJB is very simple—it only exposes four methods.
Figure 1: The Stateless Session EJB's Interface
The EJB's methods accept parameters, return usual Strings, return an array of Strings, and even return a 2D array. There is no real business logic to these methods—all of them will return dummy hardcoded strings, so you can concentrate on more important things.
The entire enterprise application (EAR) will consist of three main parts:
- The Session Stateless EJB: This has a deployment descriptor (DD) and will be deployed on the application server first.
- Apache Axis: This Web application (WAR) comes with Axis distribution. You will use it completely as a part of your EAR.
- The Configuration File (server-config.wsdd): This is where you will specify that you want to create a new Web Service. Placed this file into the WEB-INF directory of Apache Axis's WAR during compile time by the Ant script.
Figure 2: Enterprise Application Overview
Figure 3: The EJB's Web Service Configuration File
Not a single code line change is required for the business component! And the
WSDL for the Web Service is automatically generated by Axis.
| Author's Note: The server-config.wsdd file is not a configuration for one specific Web service, but for the whole Axis server. If this file does not exist, the server is configured by an automatically generated file. You can list all the Web
services which you want to be deployed on your Axis. |
The Web application (WAR) has two important JSPs: one accesses the EJB directly, and the other one accesses the EJB as a Web service. Normally, performing this kind of interaction from a JSP is a very bad practice, and I suggest you always to avoid it in your real applications. In this case, it's will be easier and won't overload this tutorial with bunch of different Java classes, etc.
The last, but not least is the standalone Java client. It is not part of the EAR, but it will access the EJB as a Web service.
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