A custom tag: empty

  <!-- this must be added to the web application's web.xml -->

<taglib>
  <taglib-uri>/java2s</taglib-uri>
  <taglib-location>/WEB-INF/java2s.tld</taglib-location>
</taglib>

// create File:java2s.tld in the /WEB-INF/
<!DOCTYPE taglib
  PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
   "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">

    <!-- a tab library descriptor -->
<taglib xmlns="http://java.sun.com/JSP/TagLibraryDescriptor">
  <tlib-version>1.0</tlib-version>
  <jsp-version>1.2</jsp-version>
  <short-name>Java2s Simple Tags</short-name>


  <!-- a tag that outputs information when different methods are called -->
  <tag>
    <name>tagLifecycle</name>
    <tag-class>com.java2s.TagLifecycle</tag-class>
    <body-content>empty</body-content>
    <attribute>
      <name>attr1</name>
    </attribute>
    <attribute>
      <name>attr2</name>
    </attribute>
  </tag>

</taglib>
//compile the following code into WEB-INF\classes\com\java2s
package com.java2s;

import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;

/* This tag handler outputs information about when different methods
   are called.
 */

public class Lifecycle extends TagSupport
{
  // Constructor

  public Lifecycle()
  {
    System.out.println("constructor called");
  }

  // Methods inherited from TagSupport

  public void setPageContext(PageContext p)
  {
    super.setPageContext(p);
    System.out.println("setPageContext() called");
  }
  
  public void setParent(Tag t)
  {
    super.setParent(t);
    System.out.println("setParent() called");
  }

  public void release()
  {
    System.out.println("release() called");
  }
  
  // Code to implement the "attr1" attribute

  private String attr1;
  public String getAttr1()
  {
    return attr1;
  }
  public void setAttr1(String s)
  {
    System.out.println("setAttr1() called with value " + s);
    attr1 = s;
  }

  // Code to implement the "attr2" attribute

  private String attr2;
  public String getAttr2()
  {
    return attr2;
  }
  public void setAttr2(String s)
  {
    System.out.println("setAttr2() called with value " + s);
    attr2 = s;
  }
  public int doStartTag() throws JspException
  {
    System.out.println("doStartTag() called");

    return SKIP_BODY;
  }

  public int doEndTag() throws JspException
  {
    System.out.println("doEndTag() called");
    return super.doEndTag();
  }
}



// start comcat and load the following jsp page in browser

<%@ taglib uri="/java2s" prefix="java2s" %>

<html>
  <head>
    <title>A custom tag: empty</title>
  </head>
  <body>
    <java2s:tagLifecycle attr1="Rob" attr2="G" />
    <java2s:tagLifecycle attr1="Joe" attr2="S" />

    Check your Tomcat console window for the output
  </body>
</html>

1.	Your own simple JSP tag
2.	Create your own tag: a custom tag body
3.	A custom tag that has neither attributes nor body content.
4.	A custom tag: empty with attributes
5.	A custom tag: scripting variable
6.	Write your own tag
7.	Logo Tag
8.	Tag lifecycle with Attribute
9.	A custom tag: iteration
10.	JSP Simple Tags
11.	JSP tag: advanced tags
12.	JSP classic tags
13.	JSP Tag Libraries and JSTL
14.	JSP Directives: HTML tag

A custom tag: empty : Tag « JSP « Java

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