Servlet Header Request

Create ./header_request directory for Servlet Header Request program in ../Apache Software Foundation/Tomcat 7.0/webapps and create following directory and file structure.

header_request
├── WEB-INF
     ├── classes
     ├    └── HelloWorld.java
     └── web.xml

Write java code in HelloWorld.java file

//Import java libraries
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

//Extends HttpServlet class
public class HeaderRequestNames extends HttpServlet {
  
    public void init() {
    }
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<table border=1>");
        Enumeration headers = request.getHeaderNames();
        while(headers.hasMoreElements())
        {
          
            String name = (String)headers.nextElement();
            out.println("<tr><td>"+name+"</td>");
            String headerValue = request.getHeader(name);
            out.println("<td>"+headerValue+"</td></tr>");
        }
        out.println("<table>");
    }
}

Write Config code in web.xml file

 

 <web-app>
    <servlet>
        <servlet-name>HeaderRequest</servlet-name>
        <servlet-class>HeaderRequestNames</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HeaderRequest</servlet-name>
        <url-pattern>/request</url-pattern>
    </servlet-mapping>
</web-app>