Objectives of this chapter
- Understand the commonly used interfaces and classes of Servlet API
- Familiar with the Servlet life cycle
- Focus on how to retrieve HTTP request parameters and form data processing
- Master the use of request objects to store data and request forwarding
- Understand how to retrieve client information and request header information
- Master how to send responses to clients and how responses are redirected
- Understanding the configuration of a web application's deployment descriptor'
- Understand the use of @WebServlet and @WebInitParam annotations
- Understand the use of the ServletConfig interface
- Learn to use ServletContext to retrieve application initialization parameters
- Master the use of ServletContext to store objects and implement request forwarding
2.1 Servlet API
The latest version of the Servlet API is Servlet4.0, which consists of the following four packages:
- The javax.servlet package defines interfaces and classes for developing protocol-independent Servlets
- The javax.servlet.http package defines the Se