React to user form input


import java.util.Enumeration;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FirstServlet extends HttpServlet {

  public void doGet(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, java.io.IOException {

    //set the MIME type of the response to "text/html"
    response.setContentType("text/html");

    //use a PrintWriter send text data to the client 
    java.io.PrintWriter out = response.getWriter();

    //output the HTML content
    out.println("<html><head>");

    out.println("<title>Help Page</title></head><body>");
    out.println("<h2>Please submit your information</h2>");

    //make sure method="post" so that the servlet service method
    //calls doPost in the response to this form submit
    out.println("<form method=\"post\" action =\""
        + request.getContextPath() + "/FirstServlet\" >");

    out.println("<table border=\"0\"><tr><td valign=\"top\">");
    out.println("Your first name: </td>  <td valign=\"top\">");
    out.println("<input type=\"text\" name=\"firstname\" size=\"20\">");
    out.println("</td></tr><tr><td valign=\"top\">");
    out.println("Your last name: </td>  <td valign=\"top\">");
    out.println("<input type=\"text\" name=\"lastname\" size=\"20\">");
    out.println("</td></tr><tr><td valign=\"top\">");
    out.println("Your email: </td>  <td valign=\"top\">");
    out.println("<input type=\"text\" name=\"email\" size=\"20\">");
    out.println("</td></tr><tr><td valign=\"top\">");

    out.println("<input type=\"submit\" value=\"Submit Info\"></td></tr>");
    out.println("</table></form>");
    out.println("</body></html>");
  } 

  public void doPost(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, java.io.IOException {

    //display the parameter names and values
    Enumeration paramNames = request.getParameterNames();

    String parName;

    boolean emptyEnum = false;
    if (!paramNames.hasMoreElements())
      emptyEnum = true;

    //set the MIME type of the response to "text/html"
    response.setContentType("text/html");

    //use a PrintWriter send text data to the client
    java.io.PrintWriter out = response.getWriter();

    //Begin assembling the HTML content
    out.println("<html><head>");
    out.println("<title>Submitted Parameters</title></head><body>");

    if (emptyEnum) {
      out.println("<h2>No parameters</h2>");
    } else {
      out.println("<h2>Here are the submitted parameter values</h2>");
    }

    while (paramNames.hasMoreElements()) {

      parName = (String) paramNames.nextElement();
      out.println("<strong>" + parName + "</strong> : "
          + request.getParameter(parName));
      out.println("<br />");
    }
    out.println("</body></html>");
  }
}
Related examples in the same category

1.	Servlets Form TextField
2.	HTML Forms with Servlets
3.	feedback Form
4.	Basic Form processor
React to user form input : Form « Servlets « Java

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