Chapter 4. Creating Web Services

IN THIS CHAPTER

• Why and What Is Axis?

• The Axis Architecture

• Installing Axis

• Configuring Axis

• Security

• Simple Web Services

• Client-Side Programming

• Advanced Web Service Deployment

• Document-Centric Services

• Data Encoding/Decoding

• Building Handlers

• Specialized Pivot Point Handlers, a.k.a. Providers

• Faults

• Message Patterns

• Building and Deploying an Intermediary

• SOAP V1.2

• Monitoring

So far, we've seen some very simple examples of Web services without going into any detail about the environment in which these Web services are running. Obviously, the SOAP implementation that comes with this book is the Axis project from the Apache Software Foundation, but we've skimmed over the details. This chapter will focus on giving a detailed overview of Axis ranging from how to configure Axis itself to how to install, configure, and write Web services. In this chapter, we review the primary or common APIs and tasks associated with using Axis, in the context of complete working examples. However, Axis has many rich features that continue to evolve. (For a complete reference to the features in Axis, see http://xml.apache.org/axis.)

While there will always be a need for new Web services that satisfy new requirements, typically Web services will be deployed to allow access to existing business logic through additional channels. By reusing the core business logic that has already been deployed and tested, a brand-new opportunity for business collaborations can be exploited by simply building a bridge between a SOAP processor and the existing business logic. This chapter will explore how to build these bridges between Axis and existing applications.