Connecting an Applet to a JSP

Connecting an applet to a JSP.

First of all, create a Java Application project with your applet in it
The submit button should read the data from the screen, encode them into a URL, and then initiate the web page using the "showDocument()" method
Note, any special characters in the data need to be converted, use the URLEncoder to do this
In the example below, a jsp file named JspForm.jsp (located in the same folder as the jar file on the web server) is invoked with the parameters lastname, firstname, age, and haircolor. Note the "?" separating the jsp file from the paramters and the "&" separating the parameters from one another. Care should be taken to make sure that special characters are not embedded in the data being passed (that is, no "=", "&", or "?" as part of the names). The output of the JSP is directed to a window called "OutputWindow" (this needs to be created in the HTML that has the applet tag), optionally the target could be "_blank", "_self", etc.

 private void
submitButtonActionPerformed(java.awt.event.ActionEvent evt) {

        // TODO add your handling
code here:

      String last = lastField.getText(); //
get data from screen

      String first = firstField.getText();

      String age = ageField.getText();

      String hair =
(String)hairCombo.getSelectedItem();

      

      //

      // fix any spaces or special characters
in the data

      // 

      try{

        last = URLEncoder.encode(last, "UTF-8");

       
first = URLEncoder.encode(first, "UTF-8");

       
age = URLEncoder.encode(age, "UTF-8");

       
hair = URLEncoder.encode(hair, "UTF-8");

      }

      catch(Exception ex)

      {

       
JOptionPane.showMessageDialog(this,ex.toString());

        return;

      }

      

      

      try{

            //
create a url with the data encoded on it

            URL link = new
URL(getCodeBase()+"JspForm.jsp?"+ 

            
"lastname="+last+ "&"+

            
"firstname="+first+ "&"+

            
"age="+age+"&"+

            
"haircolor="+hair);

           
getAppletContext().showDocument(link,"OutputWindow"); // Fire up the
jsp and tell it where to send its output

       }



        
catch(MalformedURLException ex) {

            
JOptionPane.showMessageDialog(this, "Bad URL: JspForm.jsp");

     } 

        

    }

JSP Reception of the parameters

Your JSP will have code the calls the getParameter method of the request object for each paramter. Be sure to spell the parameter names the same way in the applet ad in the JSP.

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<!DOCTYPE html>

<html>

    <head>

        <meta
http-equiv="Content-Type" content="text/html; charset=UTF-8">

        <title>JSP
Page</title>

    </head>

    <body>

        <h3>Your Information
:</h3>

        <%

         
String last = request.getParameter("lastname");

         
String first = request.getParameter("firstname");

         
String age = request.getParameter("age");

         
String haircolor = request.getParameter("haircolor");

       


       
%>

        <b>Name : <%= first+" "+last %>
</b><br/>

        <b>Age : <%= age %></b>
<br/>  

        <b>Hair Color : <%= haircolor %>
</b> <br/>

          

    </body>

</html>

Web page to contain both

In the example below, the applet is on the page and in IFrame is used to create a place for the output. The use of an IFrame is optional.

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1>Applet to JSP Connection Demo</h1>
    <Applet archive="AppletProject.jar" code="AppletForm.class" width="300" Height="260"></applet>
    <IFrame name="OutputWindow" width="300" height="300">
    </body>
</html>

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