Java Plug-in and Java Server Pages

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Java Server Pages (JSP) is a technology for generating dynamic content with a web server or application server. Since Java Server Pages 1.0, it has provided support for generating proper Java Plug-in HTML tags. This document provides an overview of the JSP support for Java Plug-in and how it can be used for deploying applets in Java Plug-in.

<jsp:plugin>

An element <jsp:plugin> was added into JSP specification "to enable a JSP page author to generate HTML that contains the appropriate client browser dependent constructs (OBJECT or EMBED) that will result in the download of the Java Plug-in Software (if required) and subsequent execution of the Applet" (JSP Specification 1.1, Page 70). 

When the JSP is executed, this <jsp:plugin> tag is replaced by either an <OBJECT> or <EMBED> tag, according to the requested browser's user agent, as specified in the Java Plug-in HTML Specification. 

For example, an applet may be specified as follows in JSP:

<jsp:plugin type=applet code="/products/plugin/1.3/docs/Molecule" codebase="/html" >
<jsp:params>
    <jsp:param name="molecule" 
		value="molecules/benzene.mol"/>     
</jsp:params>
<jsp:fallback>
       <p> unable to start plug-in </p>
</jsp:fallback>
sp:plugin>

In the above example, the attributes of the <jsp:plugin> tag provide configuration data for the applet itself. The <jsp:param> elements indicate the parameters to the applet. The <jsp:fallback> element indicates the content used by the browser if Java Plug-in fails to start.

Depending on the browser connecting to this JSP page, the web server will generate either EMBED/OBJECT tag, according to the browser's user agent.

For example, if Netscape Navigator is used to connect this JSP page, the following EMBED tag will be produced:

<EMBED type="application/x-java-applet" 
	code="Molecule" codebase="/html" 
ule="molecules/benzene.mol">
<NOEMBED>
lt;p> unable to start plug-in </p>
</NOEMBED>

For more information about the <jsp:plugin> tag, please consult the Java Server Pages Specification for more details.

Deploying Java Plug-in through JSP

JSP provides an alternative way to deploy applets through Java Plug-in, without converting the HTML pages through the HTML Converter. Because of the dynamic nature of JSP, developers will be able to generate HTML page on-the-fly that take advantage of Java Plug-in much more easily than before.

Although <jsp:plugin> tag support is part of the JSP specification, various web server or application server vendors may provide different implementations and different level of controls over this feature. For further information, please contact your server vendor.