Generating output in html or in excel format based on user input

1) HTML Input File :


<html>
<body>

<form  action="readdata" method="get" >
<fieldset>

<br/>
<b> Do you want Request Header Data? ( in Html or Excel)" : </b>
<input type="radio" name="doctype" value="html" checked /> Html
<input type="radio" name="doctype" value="excel" /> Excel
<br/>
<input type="submit" />
</fieldset>
</form>

</body>

2) Servlet that generate dynamic content (in html or in excel format ) based on user input :

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

import java.util.Enumeration;

public class ServletReadData extends HttpServlet {

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {

   

String sdoctype = request.getParameter("doctype");

if (sdoctype.equals("html")) {

response.setContentType("text/html"); }

else if (sdoctype.equals("excel") )

{ response.setContentType("application/vnd.ms-excel"); }

   

PrintWriter out = response.getWriter();

out.println("<html> <head> <title> First Servlet ... </title></head>");

out.println("<body> <h1> Java Servlet Request Header Reading.. </h1>");

       Enumeration myheader =request.getHeaderNames();

out.println( "<table border='2'> <tr> <th> Header Name </th><th> Header Values </th> </tr>");

while (myheader.hasMoreElements() )

{

String myhname =(String) myheader.nextElement();

//Header Name

out.println("<tr> <td>");

out.println( myhname);

out.println("</td>");

//values of header

Enumeration myhvalue = request.getHeaders(myhname);

out.println("<td>");

while (myhvalue.hasMoreElements() )

{

out.println(myhvalue.nextElement());

}

out.println("</td>");

out.println("</tr>");

}

out.println("</body></html>" );

  }  //end of doPost method

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {

doPost(request, response);

  }  //end of doGet method

}

Servlet Reading HTTP Request Headers and values associated with each request header

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.Enumeration;

public class ServletReadData extends HttpServlet {

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {
    response.setContentType("text/html");

PrintWriter out = response.getWriter();
out.println("<html> <head> <title> First Servlet ... </title></head>");
out.println("<body> <h1> Java Servlet Request Header Reading.. </h1>");

Enumeration myheader =request.getHeaderNames();

out.println( "<table border='2'> <tr> <th> Header Name </th><th> Header Values </th> </tr>");
while (myheader.hasMoreElements() )
{
String myhname =(String) myheader.nextElement();
//Header Name
out.println("<tr> <td>");
out.println( myhname);
out.println("</td>");
//values of header
Enumeration myhvalue = request.getHeaders(myhname);
out.println("<td>");
while (myhvalue.hasMoreElements() )
{
out.println(myhvalue.nextElement());
}
out.println("</td>");
out.println("</tr>");

}

out.println("</body></html>" );

  }  //end of doPost method

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {
doPost(request, response);
  }  //end of doGet method


} // end of class

_______________________________________________________________________________

The output of the Above Servlet Program:

Java Servlet Request Header Reading..

Header Name	Header Values
host	localhost:8080
connection	keep-alive
content-length	53
cache-control	max-age=0
accept	text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
origin	http://localhost:8080
user-agent	Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.111 Safari/537.36
content-type	application/x-www-form-urlencoded
referer	http://localhost:8080/awtad2015/callservlet.html
accept-encoding	gzip, deflate
accept-language	en-US,en;q=0.8

Servlet with getRequestParameter and getParameterValues methods and HTML Form example

1) HTML Form File 


<html>
<body>
<!--
<a href="http://localhost:8080/awtad2015/html/file.aspx"> ServletDemo </a>
-->

<form  action="readdata" method="post" >
<fieldset>
<legend> Institute Information </legend>
Institute Name :
<input type="text" name="iname" value="ISTAR"/> <br>
Place :
<input type="radio" name="place" value="City" checked />City &nbsp;
<input type="radio" name="place" value="Village"  /> Village&nbsp;
<input type="radio" name="place" value="Town"  />Town &nbsp;
<br>
<hr width="30%" align="left"/>
<input type="checkbox" name="course" value="MCA" checked />MCA &nbsp;
<input type="checkbox" name="course" value="MSc.(IT)" checked />MSc.(IT) &nbsp;
<input type="checkbox" name="course" value="MSc(Est)"  />MSc(EST) &nbsp;
<input type="submit" />
</fieldset>
</form>

</body>

</html>



2) Servlet Class:  ServletReadData 


import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class ServletReadData extends HttpServlet {

  public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {
    response.setContentType("text/html");

PrintWriter out = response.getWriter();
out.println("<html> <head> <title> First Servlet ... </title></head>");
out.println("<body> <h1> Welcome to JAVA  </h1>");


out.println("Hello World <br>" );

String siname = request.getParameter("iname");
String splace = request.getParameter("place");

out.println("Institute Name : "+ siname + "<br>");
out.println("Place Name : " + splace);
String courses[] = request.getParameterValues("course");
out.println("<br> Course Name : ");
for (String cname : courses)
{
out.println(cname + "<br>");
}


out.println("</body></html>" );

  }  //end of doPost method

 public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

  {
doPost(request, response);
  }  //end of doGet method


}



3) web.xml entry for ServletReadData

<web-app ...
>
....................

  <servlet>
      <servlet-name>ServletRead</servlet-name>
      <servlet-class>ServletReadData</servlet-class>
  </servlet>

    <servlet-mapping>
      <servlet-name>ServletRead</servlet-name>
      <url-pattern>/readdata</url-pattern>
    </servlet-mapping>
  .....
......
  </web-app>