Servlet Tutorials

GenericServlet class implements Servlet, ServletConfig and Serializable interfaces. which is provides a implementaion of all the methods of these interfaces except the service method.

GenericServlet can handle any type of request so it is protocol-independent.

We can be create a generic servlet by inheriting the GenericServlet class which providing the implementation of the service method.

GenericServlet class as follows:

    public void init(ServletConfig config) is used to initialize the servlet.
    public abstract void service(ServletRequest request, ServletResponse response)
	provides service for the incoming request. It is invoked at each time when user
	requests for a servlet.
    public void destroy() is invoked only once throughout the life cycle
	and indicates that servlet is being destroyed.
    public ServletConfig getServletConfig() returns the object of ServletConfig.
    public String getServletInfo() returns information about servlet such
	as writer, copyright, version etc.
    public void init() it is a convenient method for the servlet programmers, 
	now there is no need to call super.init(config)
    public ServletContext getServletContext() returns the object of ServletContext.
    public String getInitParameter(String name) returns the parameter value
	for the given parameter name.
    public Enumeration getInitParameterNames() returns all the parameters
	defined in the web.xml file.
    public String getServletName() returns the name of the servlet object.
    public void log(String msg) writes the given message in the servlet log file.
    public void log(String msg,Throwable t) writes the explanatory message
	in the servlet log file and a stack trace.

Example

import java.io.*;
import javax.servlet.*;
public class First extends GenericServlet{
public void service(ServletRequest req,ServletResponse res)
throws IOException,ServletException{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
out.print("<html><body>");
out.print("<b>hello generic servlet</b>");
out.print("</body></html>");
}
}