Dinesh on Java

Struts2

Struts 2 – The generator tag

In this tutorial, we are going to describe the generator tag. The generator tag is a generic tag that is used to generate iterators based on different attributes passed. Here we will not pass any attribute.

Create action class:
ControlTagAction.java

package com.tutorialspoint.struts2;

public class ControlTagAction{
   private String name;

   public String execute() throws Exception {
      return "success";
   }
   
   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }
}

Create views
Let us have generator.jsp to demonstrate the use of the generator tag:

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Generator Control Tag Struts2 | dineshonjava.com</title>
</head>
<body>

<h1><span style="background-color: #FFFFcc">Example of Generator! | dineshonjava.com</span></h1>
<h3>The Name of Students:</h3>

<s:generator val="%{'Dinesh,Sweety,Ankit,
         Adesh,Vinesh,Anamika,Raaz}" count="7" 
         separator=",">
   <s:iterator>
      <s:property />

   </s:iterator>
</s:generator> 
 
</body>
</html>

Here we are creating a generator tag and we ask it to parse the string that contains comma separated list of colors that form a rainbow. We tell the generator tag that the separator is “,” and we want all seven values in the list. If we are only interested in the first three values, then we would set the count to 3. In the body of the generator tag, we used the iterator to go through the values created by the generator tag and we print the value of the property.

Configuration Files
Your struts.xml should look like:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
 
<struts>
    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="false" />
    <constant name="struts.custom.i18n.resources" value="myapp" />
 
    <package name="default" extends="struts-default" namespace="/">
        <action name="generatortag" class="com.dineshonjava.struts2.action.ControlTagAction">
            <result name="success">/generator.jsp</result>
        </action>
        
    </package>
 </struts>

Your web.xml should look like:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Struts2ControlTags</display-name>
  <filter>
        <filter-name>struts2</filter-name>
        <filter-class>
            org.apache.struts2.dispatcher.FilterDispatcher
        </filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

Right click on the project name and click Export > WAR File to create a War file. Then deploy this WAR in the Tomcat’s webapps directory. Finally, start Tomcat server and try to access

URL http://localhost:8080/doj/generatortag.
This will give you following screen:

Download Source Code
Struts2GeneratorTag.zip

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Dinesh Rajput

Dinesh Rajput is the chief editor of a website Dineshonjava, a technical blog dedicated to the Spring and Java technologies. It has a series of articles related to Java technologies. Dinesh has been a Spring enthusiast since 2008 and is a Pivotal Certified Spring Professional, an author of a book Spring 5 Design Pattern, and a blogger. He has more than 10 years of experience with different aspects of Spring and Java design and development. His core expertise lies in the latest version of Spring Framework, Spring Boot, Spring Security, creating REST APIs, Microservice Architecture, Reactive Pattern, Spring AOP, Design Patterns, Struts, Hibernate, Web Services, Spring Batch, Cassandra, MongoDB, and Web Application Design and Architecture. He is currently working as a technology manager at a leading product and web development company. He worked as a developer and tech lead at the Bennett, Coleman & Co. Ltd and was the first developer in his previous company, Paytm. Dinesh is passionate about the latest Java technologies and loves to write technical blogs related to it. He is a very active member of the Java and Spring community on different forums. When it comes to the Spring Framework and Java, Dinesh tops the list!