Because of keep the usage of servlets in mind I created a simple servlet example. In the majority of cases servlets are the core structure elements of Java web applications. More precisely if I spoke about a servlet I mean the HttpServlet Java class. The HttpServlet class provides methods for standard HTTP operations how PUT, GET, POST or DELETE. Servlet methods have two input parameters. First the HttpServletRequest object parameter that represents a basic HTTP request (e.g. http://developers-blog.org/?param=2). Second the HttpServletResponse object parameter that defines the response. The getWriter() method of the HttpServletResponse object enables to write the response.
Example:
package org.developers.blog.examples.web.servlet;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
//URL - example.com/helloservlet/?myname=rafael
String hisname = request.getParameter("myname");
PrintWriter out = response.getWriter();
out.println("<html>\n" +
"<body>\n" +
"<h1>Hello" + hisname + ".</h1>\n" +
"</body>\n" +
"</html>");
}
}
Definition in web.xml file
<servlet> <servlet-name>helloservlet</servlet-name> <servlet-class>org.developers.blog.examples.web.servlet.HelloServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>hello</servlet-name> <url-pattern>/helloservlet</url-pattern> </servlet-mapping>
Additionaly you can easily access to HTTP header information, access to cookies, create sessions and so on.
Regards
Rafael
Technorati Tags: Java Servlet Servlet Example
<servlet>
<servlet-name>helloservlet</servlet-name>
<servlet-class>org.developers.blog.examples.web.servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hello</servlet-name>
<url-pattern>/helloservlet</url-pattern>
</servlet-mapping>
In above web.xml, servlet-name are different is it valid one ?