GenericServlet class
GenericServlet classimplements Servlet, ServletConfig and Serializable interfaces.
It provides the implementation of all the methods of these interfaces except
the service method.
GenericServlet
class can handle any type of request so it is protocol-independent.
You
may create a generic servlet by inheriting the GenericServlet class and
providing the implementation of the service method.
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Fig: GenericServlet |
Methods of GenericServlet class
There
are many methods in GenericServlet class. They are as follows:
1.
public
void init(ServletConfig config) is used to initialize the servlet.
2.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.
3.public
void destroy() is
invoked only once throughout the life cycle and indicates that servlet is being
destroyed.
4.public
ServletConfig getServletConfig() returns the object of
ServletConfig.
5.
public
String getServletInfo() returns information about servlet
such as writer, copyright, version etc.
6.public
void init() it
is a convenient method for the servlet programmers, now there is no need to
call super.init(config)
7.public
ServletContext getServletContext() returns the object of
ServletContext.
8.
public
String getInitParameter(String name) returns the parameter value
for the given parameter name.
9.public
Enumeration getInitParameterNames() returns all the parameters defined
in the web.xml file.
10.public
String getServletName() returns the name of the servlet
object.
11. public
void log(String msg) writes the given message in the servlet log
file.
12. public
void log(String msg,Throwable t) writes the explanatory message in
the servlet log file and a stack trace.
There
are many methods in GenericServlet class. They are as follows:
1.
public
void init(ServletConfig config) is used to initialize the servlet.
2.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.
3.public
void destroy() is
invoked only once throughout the life cycle and indicates that servlet is being
destroyed.
4.public
ServletConfig getServletConfig() returns the object of
ServletConfig.
5.
public
String getServletInfo() returns information about servlet
such as writer, copyright, version etc.
6.public
void init() it
is a convenient method for the servlet programmers, now there is no need to
call super.init(config)
7.public
ServletContext getServletContext() returns the object of
ServletContext.
8.
public
String getInitParameter(String name) returns the parameter value
for the given parameter name.
9.public
Enumeration getInitParameterNames() returns all the parameters defined
in the web.xml file.
10.public
String getServletName() returns the name of the servlet
object.
11. public
void log(String msg) writes the given message in the servlet log
file.
12. public
void log(String msg,Throwable t) writes the explanatory message in
the servlet log file and a stack trace.
Example by inheriting the GenericServlet class
import java.io.*;
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>");
}
}
Hello, my name is Pramod Dwivedi. I'm a 5 year old self-employed in online business Industry.
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