Communication between Applet and Servlet

by Vinoth 2008-12-22 01:16:20

Hi,
Just compile bellow java class and call the applet using html file.
AppletEcho.java

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
public class AppletEcho extends Applet {
private TextField inputField = new TextField();
private TextField outputField = new TextField();
private TextArea exceptionArea = new TextArea();
public void init() {
setLayout(new GridBagLayout());
Label title = new Label("Echo Applet", Label.CENTER);
title.setFont(new Font("SansSerif", Font.BOLD, 14));
GridBagConstraints c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.weightx = 1.0;
c.fill = GridBagConstraints.HORIZONTAL;
c.insets = new Insets(5, 5, 5, 5);
add(title, c);
c = new GridBagConstraints();
c.anchor = GridBagConstraints.EAST;
add(new Label("Input:", Label.RIGHT), c);
c = new GridBagConstraints();
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 1.0;
add(inputField, c);
Button sendButton = new Button("Send");
c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
add(sendButton, c);
sendButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
onSendData();
}
});

// add output label and non-editable field
c = new GridBagConstraints();
c.anchor = GridBagConstraints.EAST;
add(new Label("Output:", Label.RIGHT), c);
c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = 1.0;
add(outputField, c);
outputField.setEditable(false);

// add exception label and non-editable textarea
c = new GridBagConstraints();
c.anchor = GridBagConstraints.EAST;
add(new Label("Exception:", Label.RIGHT), c);
c = new GridBagConstraints();
c.gridwidth = GridBagConstraints.REMAINDER;
c.weighty = 1;
c.fill = GridBagConstraints.BOTH;
add(exceptionArea, c);
exceptionArea.setEditable(false);
}
private URLConnection getServletConnection()
throws MalformedURLException, IOException {

//URL url=new java.net.URL
URL urlServlet = new URL(getCodeBase(), "echo");
URLConnection con = urlServlet.openConnection();

// konfigurieren
con.setDoInput(true);
con.setDoOutput(true);
con.setUseCaches(false);
con.setRequestProperty(
"Content-Type",
"application/x-java-serialized-object");

return con;
}

/*Send the inputField data to the servlet and show the result in the outputField. */
private void onSendData() {
try {
String input = inputField.getText();
// send data to the servlet
URLConnection con = getServletConnection();
OutputStream outstream = con.getOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(outstream);
oos.writeObject(input);
oos.flush();
oos.close();

// receive result from servlet
InputStream instr = con.getInputStream();
ObjectInputStream inputFromServlet = new ObjectInputStream(instr);
String result = (String) inputFromServlet.readObject();
inputFromServlet.close();
instr.close();

// show result
outputField.setText(result);

} catch (Exception ex) {
ex.printStackTrace();
exceptionArea.setText(ex.toString());
}
}
}



Just add the class file in index.html and run it.

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