Servlet Programming

As soon as the Web began to be used for delivering services, service providers recognized the need for dynamic content. Applets, one of the earliest attempts towards this goal, focused on using the client platform to deliver dynamic user experiences.

At the same time, developers also investigated using the server platform for this purpose. Initially, Common Gateway Interface (CGI) scripts were the main technology used to generate dynamic content. Though widely used, CGI scripting technology has a number of shortcomings, including platform dependence and lack of scalability. To address these limitations, Java Servlet technology was created as a portable way to provide dynamic, user-oriented content.

A servlet is a Java programming language class used to extend the capabilities of servers that host applications accessed via a request-response programming model. Although servlets can respond to any type of request, they are commonly used to extend the applications hosted by Web servers. For such applications, Java Servlet technology defines HTTP-specific servlet classes.

The javax.servlet and javax.servlet.http packages provide interfaces and classes for writing servlets. All servlets must implement the Servlet interface, which defines life-cycle methods.

When implementing a generic service, you can use or extend the GenericServlet class provided with the Java Servlet API.

The HttpServlet class provides methods, such as doGet and doPost, for handling HTTP-specific services.