How can I create custom tag in JSP which can accept attribute from parent jsp page?


You can use various attributes along with your custom tags. To accept an attribute value, a custom tag class needs to implement the setter methods, identical to the JavaBean setter methods as shown below −

package com.tutorialspoint;

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

public class HelloTag extends SimpleTagSupport {
   private String message;
   public void setMessage(String msg) {
      this.message = msg;
   }
   StringWriter sw = new StringWriter();
   public void doTag()
   throws JspException, IOException {
      if (message != null) {
         /* Use message from attribute */
         JspWriter out = getJspContext().getOut();
         out.println( message );
      } else {
         /* use message from the body */
         getJspBody().invoke(sw);
         getJspContext().getOut().println(sw.toString());
      }
   }
}

The attribute's name is "message", so the setter method is setMessage(). Let us now add this attribute in the TLD file using the <attribute> element as follows −

<taglib>
   <tlib-version>1.0</tlib-version>
   <jsp-version>2.0</jsp-version>
   <short-name>Example TLD with Body</short-name>

   <tag>
      <name>Hello</name>
      <tag-class>com.tutorialspoint.HelloTag</tag-class>
      <body-content>scriptless</body-content>

      <attribute>
      <name>message</name>
      </attribute>

   </tag>
</taglib>

Let us follow JSP with message attribute as follows −

<%@ taglib prefix = "ex" uri = "WEB-INF/custom.tld"%>

<html>
   <head>
      <title>A sample custom tag</title>
   </head>

   <body>
      <ex:Hello message = "This is custom tag" />
   </body>
</html>

This will produce the following result −

This is custom tag

karthikeya Boyini
karthikeya Boyini

I love programming (: That's all I know

Updated on: 30-Jul-2019

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