Custom tags are usually distributed in the form of a tag library, which defines a set of related custom tags and contains the objects that implement the tags.
A Simple Custom tags Example:
1.Create a Java Program
2.import javax.servlet.jsp.*,javax.servlet.jsp.tagext.* packages
3.Extends the TagSupport Class
4.Java Program Contain two Default Methods.
a)doStartTag
b)doEndTag
doStartTag:
1.The doStartTag method is invoked when the start tag is encountered
2.This method returns SKIP_BODY because a simple tag has no body
doEndTag:
1.The doEndTag method is invoked when the end tag is encountered
2.This method returns SKIP_BODY because a simple tag has no body
TagClass.java
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
public class TagClass extends TagSupport{
private String data=null;
public void setData(String value){
data= value;
}
public String getData(){
return(data);
}
public int doStartTag()throws JspException{
try{
JspWriter out=pageContext.getOut();
out.println(name);
}catch(Exception e){}
return SKIP_BODY;
}
public int doEndTag(){
return SKIP_BODY;
}
}
5.The Java Program Contain one Variable data(which has Getter and Setter Methods)
6.Create tld File.
7.We have to Create attribute For the Variable data
8.Syntax For Creating attribute:
<taglib>
<tag>
<attribute>
<name>data</name>//Name Can be Same as we can given within the tags
<required>true</required>//Requried Field Show Whether it is Mandatory or Not
</attribute>
<attribute>
<name>id</name>
<required>false</required>
</attribute>
</tag>
</taglib>
taglib.tld
<?xml version=”1.0″ encoding=”ISO-8859-1″ ?>
<!DOCTYPE taglib PUBLIC “-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN” “http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd”>
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>1.2</jsp-version>
<short-name>form</short-name>
<tag>
<name>Show</name>
<tag-class>com.TagClass</tag-class>
<body-content>JSP</body-content>
<description>Simple Customs tags Example</description>
<attribute>
<name>data</name>
<required>true</required>
</attribute>
</tag>
</taglib>
9.Create a JSP Page.
10.Include this tag at the begining of the JSP Page
<%@ taglib uri=”/WEB-INF/tld/taglib.tld” prefix=”custom” %>
11.Create this Tag at the JSP Page
<custom:Show data=”Custom Tag Example”></custom:Show>
12.Output:
Custom Tag Example
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