Java JSP With A Custom Tag

HelloTag.jsp

<%@page contentType="text/html"%>
<html>
<head><title>Hello Tags Page</title></head>
<body>

<%@ taglib uri="/WEB-INF/classes/tags/helloTag.tld" prefix="hello" %>

<hello:helloTag />

</body>
</html>

download source, use right-click and "Save Target As..." to save with a .jsp extension.

HelloTag.java

package tags;  //note: must be in a package

import java.io.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

public class HelloTag extends TagSupport {
    public int doStartTag() {
        try {
            //use JspWriter to get output to your JSP
            JspWriter jspWriterOutput = pageContext.getOut();
            jspWriterOutput.print("Hello Tag!");
        } catch (IOException ioEx) {
            System.out.println("IOException in HelloTag " + ioEx);
        }
        return (SKIP_BODY);
    }
}

download source, use right-click and "Save Target As..." to save with a .java extension.

helloTag.tld

<?xml version="1.0" encoding="UTF-8" ?><br /><br />
<!DOCTYPE taglib
        PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"><br /><br />
<taglib>
    <tlib-version>1.0</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>helloTag</short-name>
    <uri>/WEB-INF/tags/helloTag</uri>
    <display-name>helloTag</display-name>
    <small-icon></small-icon>
    <large-icon></large-icon>
    <description>simple hello tags tag
    </description>
    <tag>
        <name>helloTag</name>
        <tag-class>tags.HelloTag</tag-class>
        <body-content>empty</body-content>
        <small-icon></small-icon>
        <large-icon></large-icon>
        <description></description>
        <example></example>
    </tag>
</taglib>

Notes

The helloTag I show was generated by NetBeans, and then I modified it just a little. I generally like to code my own XML files, but even the Sun tutorial on custom tags suggests letting your ide do it.

The tld files can be put directly into WEB-INF. I accidentally put mine in the directory with the tag class file, and I now prefer it that way.

References

online
The Java 2 Platform Specification
Books
Core JSP by Damon Hougland and Aaron Tavistock
Core Servlets and JavaServer Pages by Marty Hall

Comments Comments are left by visitors to FluffyCat.com and may or may not be accurate.

Comment by ramesh on 2008-05-12 Rate this Comment

this will be very usefull for beginners