Chapter 4. HTTP Protocol: Web Application Communications and Control

IN THIS CHAPTER

• HTTP Protocol and the Request/Response Cycle

• Control Information: HTTP Headers and HTTP Response Codes

• HTTP Cookies and Session/ User Management

• Conclusions

This chapter provides a basic grounding in HTTP communications and the underlying technologies used for building applications in which the application is a browser.

Understanding the underlying protocol of Web applications is well worth the time spent learning about it. The HTTP protocol provides the basis for everything built on top of it (including browser communications, Web servers, servlet containers, servlets, and even Struts itself). Having a good basic understanding of HTTP is essential in helping you pick up the technology quickly and debugging issues when things go wrong.

In keeping with our series title, Kick Start , this chapter goes fast and covers a lot of ground. You'll acquire, in one chapter, a good, detailed working knowledge of the following topics:

• The basics of HTTP communications and how this protocol governs the request/response cycle in JSP and Struts

• How HTTP cookies work and their implications for user session management in JSP and Struts

• HTTP headers and HTTP response codes and how they are used in developing JSP and Struts applications