BeginnersBookDemo/src/ReadParams.java


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

// Extend HttpServlet class
public class ReadParams extends HttpServlet {

   /**
    * 
    */
   private static final long serialVersionUID = 1L;

   // Method to handle GET method request.
   public void doGet(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {

      // Set response content type
      response.setContentType("text/html");

      PrintWriter out = response.getWriter();
      String title = "Reading All Form Parameters";
      String docType = "<!doctype html public \"-//w3c//dtd html 4.0 " + "transitional//en\">\n";

      out.println(docType +
            "<html>\n" +
            "<head><title>" + title + "</title></head>\n" +
            "<body bgcolor = \"#f0f0f0\">\n" +
            "<h1 align = \"center\">" + title + "</h1>\n" +
            "<table width = \"100%\" border = \"1\" align = \"center\">\n" +
            "<tr bgcolor = \"#949494\">\n" +
            "<th>Param Name</th>" +
            "<th>Param Value(s)</th>\n" +
            "</tr>\n");

      Enumeration paramNames = request.getParameterNames();

      while (paramNames.hasMoreElements()) {
         String paramName = (String) paramNames.nextElement();
         out.print("<tr><td>" + paramName + "</td>\n<td>");
         String[] paramValues = request.getParameterValues(paramName);

         // Read single valued data
         if (paramValues.length == 1) {
            String paramValue = paramValues[0];
            if (paramValue.length() == 0)
               out.println("<i>No Value</i>");
            else
               out.println(paramValue);
         } else {
            // Read multiple valued data
            out.println("<ul>");

            for (int i = 0; i < paramValues.length; i++) {
               out.println("<li>" + paramValues[i]);
            }
            out.println("</ul>");
         }
      }
      out.println("</tr>\n</table>\n</body></html>");
   }

   // Method to handle POST method request.
   public void doPost(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {

      doGet(request, response);
   }
}