jsp:plugin, jsp:params and jsp:fallback actions examples

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Last Updated on 22 July 2019   |   Print  Email


The <jsp:plugin> action is used to generate browser-dependent HTML code (OBJECTor EMBED) that displays and executes a Java Plugin software (Java applet or a JavaBean component) in the current JSP page. The <jsp:params> and <jsp:fallback> actions are optional sub elements. Here’s a quick example:

<jsp:plugin
    type="applet"
    code="net.codejava.applet.MyApplet.class"
    codebase="html">

    <jsp:params>
        <jsp:param name="username" value="Tom" />
    </jsp:params>

    <jsp:fallback>
        <p>Could not load applet!</p>
    </jsp:fallback>

</jsp:plugin>

 

1. Syntax of JSP plugin action

Following is the complete syntax of the <jsp:plugin> action:

<jsp:plugin type="bean|applet"

       code="objectCode"

       codebase="objectCodebase"

 

       {optional attributes}

 

       { <jsp:params>

              { <jsp:param name="paramName" value="paramValue" /> }+

       </jsp:params> }

 

       { <jsp:fallback> arbitrary_text </jsp:fallback> }

 

</jsp:plugin>

The optional attributes are described in the Attributes Description section below.

The <jsp:params> and <jsp:fallback> elements are optional. If the <jsp:params> element is specified, it must contain at least one sub element <jsp:param>.

 

2. Attributes of JSP plugin action

Attribute name

Required

Description

type

Yes

Specifies type of the component: applet or bean.

code

Yes

Class name of the applet or JavaBean, in the form of packagename.classname.class.

codebase

Yes

Base URL that contains class files of the component.

align

Optional

Alignment of the component. Possible values are: left, right, top, middle, bottom.

archive

Optional

Specifies a list of JAR files which contain classes and resources required by the component.

height, width

Optional

Specifies height and width of the component in pixels.

hspace, vspace

Optional

Specifies horizontal and vertical space between the component and the surrounding components, in pixels.

jreversion

Optional

Specifies JRE version which is required by the component. Default is 1.2.

name

Optional

Name of the component.

title

Optional

Title of the component.

nspluginurl,

iepluginurl

Optional

Specifies URL where JRE plugin can be downloaded for Netscape or IE browser, respectively.

mayscript

Optional

Accepts true/false value. If true, the component can access scripting objects (Javascript) of the web page.

 

3. <jsp:params> action

This action is an optional, direct child of the <jsp:plugin> action. It cannot be used elsewhere. If specified, it must contain one or more <jsp:param> actions to provide additional parameters for the component. For example:

<jsp:params>

	<jsp:param name="param1" value="value1" />

	<jsp:param name="param2" value="value2" />

</jsp:params>

 

4. <jsp:fallback> action

This action is an optional, direct child of the <jsp:plugin> action. Its purpose is to specify some content which is used by the client browser in case the plugin cannot be started. Common usage is to show some text that indicates there’s a problem of loading the component. For example:

<jsp:fallback>
	<p>Could not load applet!</p>
</jsp:fallback>

This action cannot be used elsewhere outside the <jsp:plugin> action.

 

5. JSP plugin action Examples

Let’s see an example in which we create a simple Java applet class and use the <jsp:plugin> action to run the applet on a JSP page.

Code of the applet:

package net.codejava.applet;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;

import javax.swing.JApplet;
import javax.swing.JLabel;

public class MyApplet extends JApplet {
	
	private JLabel label = new JLabel();
	
	public void init() {
		label.setHorizontalAlignment(JLabel.CENTER);
		label.setFont(new Font("Arial", Font.BOLD, 20));
		label.setForeground(Color.BLUE);
		
		setLayout(new BorderLayout());
		add(label, BorderLayout.CENTER);
	}
	
	public void start() {
		String firstName = getParameter("firstName");
		String lastName = getParameter("lastName");
		label.setText("Hello " + firstName + " " + lastName);
	}
}

 

Code of the JSP page:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
	"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Plugin action Demo</title>
</head>
<body>
	<div align="center">
		<jsp:plugin 
			type="applet"
			code="net.codejava.applet.MyApplet.class" 
			codebase="appletCode"
			align="">
			
			<jsp:params>
				<jsp:param name="firstName" value="James" />
				<jsp:param name="lastName" value="Bond" />
			</jsp:params>
			
			<jsp:fallback>
				<p>Could not load applet!</p>
			</jsp:fallback>
			
		</jsp:plugin>
	</div>
</body>
</html>

Output when running the PluginDemo.jsp page:

JSP Plugin Demo run Java applet

 

Other JSP actions:

 

Other JSP Tutorials:


About the Author:

is certified Java programmer (SCJP and SCWCD). He began programming with Java back in the days of Java 1.4 and has been passionate about it ever since. You can connect with him on Facebook and watch his Java videos on YouTube.



Attachments:
Download this file (JspPluginDemo.war)JspPluginDemo.war[Deployable WAR file]4 kB

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