A Tag And A Business Service

In this tutorial we will discuss an example of using a business service in the Action class with a tag in the JSP file. Business Service is the class where we put the business logic on the coming request and return the value to the response. In the following figure we will see that how to flow the request between the Action and Business Service and View.
Business service return the data to the action and action return the these data as a response to the client with associated view. 

In the JSP file data return by the business service assigned to variable in the action class this variable assign to the JSP file with using a TAG. <s:property/>.

Look the following example using a simple business service with <s:property/> tag.

After creating directory structure add the following code to the files.

web.xml
<?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>Struts2TutorialFinder</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>success.jsp</welcome-file>
    </welcome-file-list>
</web-app>
struts.xml
<?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="/tutorials">
        <action name="getTutorial" class="com.dineshonjava.struts2.action.TutorialAction">
            <result name="success">/success.jsp</result>
            <result name="error">/error.jsp</result>
        </action>
    </package>
    
</struts>
In the above struts configuration file we are using the package with namespace "/tutorials". And action name is "getTutorial" with the TutorialAction class. If return success for success.jsp and error with error.jsp.
TutorialAction.java
package com.dineshonjava.struts2.action;

import com.dineshonjava.struts2.service.TutorialFinderService;

/**
 * @author Dinesh Rajput
 *
 */
public class TutorialAction {
 private String bestTutorialSite;
 public String execute() {
  TutorialFinderService finderService = new TutorialFinderService();
  String bestSite = finderService.getBestTutorialSite();
  setBestTutorialSite(bestSite);
  System.out.println(bestSite);
  return "success";
 }
 public String getBestTutorialSite() {
  return bestTutorialSite;
 }
 public void setBestTutorialSite(String bestTutorialSite) {
  this.bestTutorialSite = bestTutorialSite;
 }
 
}

In the above tutorial action class we are using the business service "TutorialFinderService.java" for operating some business logic to the data. Business service has one method "getBestTutorialSite()" which return the name of the best tutorial site to the Action class and this value set to the variable "bestTutorialSite".
TutorialFinderService.java
package com.dineshonjava.struts2.service;

/**
 * @author Dinesh Rajput
 *
 */
public class TutorialFinderService {
 public String getBestTutorialSite(){
  return "www.dineshonjava.com";
 }
}

The above class is business service class which define the business logic.
success.jsp
<%@ page contentType="text/html; charset=UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Success | dineshonjava.com</title>
</head>
 
<body>
    <h2>Business Service Executed!!! 
    <s:property value="bestTutorialSite"/></h2>
</body>
</html>
In the above JSP file we are using one TAG for display the value of variable which assigned in the Action class using the following TAG name.

<s:property value="bestTutorialSite"/>



Download SourceCode + Libs
Struts2TutorialFinder.zip



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