Custom tags:
Custom tags are the user defined tags. These tags are mainly used for code re-usability. We can define a custom tag with any number of attributes. Let us discuss it with the below example.
Example:
CustomTagWithAttribute.java
import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
* This class is used for defining a custom tag with attributes.
* @author javatutorialpoint
*/
public class CustomTagWithAttribute extends SimpleTagSupport{
//tag attribute
private int num;
public void doTag() throws JspException, IOException {
JspWriter out = getJspContext().getOut();
try{
out.println("Square of " + num + " = " + num * num);
}catch(Exception e){
e.printStackTrace();
}
}
public void setNum(int num) {
this.num = num;
}
}
|
squaretag.tld
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>2.0</jsp-version>
<short-name>Our first custom tag</short-name>
<tag>
<name>squareTag</name>
<tag-class>
com.javawithease.customtags.CustomTagWithAttribute
</tag-class>
<body-content>empty</body-content>
<attribute>
<name>num</name>
<required>true</required>
</attribute>
</tag>
</taglib>
|
test.jsp
<%@ taglib prefix="stag" uri="WEB-INF/squaretag.tld"%>
<html>
<head>
<title>custom tag with attribute example</title>
</head>
<body>
<stag:squareTag num="25"/>
</body>
</html>
|
web.xml
<web-app>
<welcome-file-list>
<welcome-file>test.jsp</welcome-file>
</welcome-file-list>
</web-app>
|
Output:
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