Component Roles in the SSH Stack

Struts2 – Acts as the web layer controller. It routes HTTP requests to appropriate business logic via its central servlet (ActionServlet) and configuration defined in struts.xml.

Spring – Functions as the integration backbone using Inversion of Control (IoC) to decouple components, enabling seamless collaboration among the three frameworks.

Hibernate – Serves as the persistence layer. It maps relational database schemas to object-oriented models, allowing developers to manipulate data using objects instead of SQL.

Framework Versions Used

• Struts2: 2.3.15.3
• Spring: 3.2.0
• Hibernate: 3.6.10

Required Libraries

Struts2 Dependencies

• All JARs from struts-2.3.15.3/apps/struts-blank/WEB-INF/lib
• struts2-convention-plugin-2.3.15.3.jar for annotation-based actions
• struts2-spring-plugin-2.3.15.3.jar for Spring integration

Hibernaet Dependencies

• hibernate3.jar from root distribution
• All JARs in hibernate/lib/required
• hibernate-entitymanager-2.0.Final.jar
• Logging bridge: slf4j-log4j12-1.7.5.jar
• MySQL JDBC driver: mysql-connector-java-5.1.25-bin.jar

Spring Dependencies

Core IoC:

• spring-beans-3.2.5.RELEASE.jar
• spring-context-3.2.5.RELEASE.jar
• spring-core-3.2.5.RELEASE.jar
• spring-expression-3.2.5.RELEASE.jar
• com.springsource.org.apache.log4j-1.2.15.jar
• com.springsource.org.apache.commons.logging-1.1.1.jar

AOP and Supporting Modules:

• spring-aop-3.2.5.RELEASE.jar
• spring-aspects-3.2.5.RELEASE.jar
• com.springsource.org.aopalliance-1.0.0.jar
• com.springsource.org.aspectj.weaver-1.6.8.RELEASE.jar
• spring-jdbc-3.2.5.RELEASE.jar
• spring-test-3.2.5.RELEASE.jar
• spring-web-3.2.5.RELEASE.jar
• spring-orm-3.2.5.RELEASE.jar
• spring-tx-3.2.5.RELEASE.jar

Configuration Files

Struts2 Setup

web.xml

<filter>
    <filter-name>strutsDispatcher</filter-name>
    <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>strutsDispatcher</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

struts.xml

<?xml version="1.0" encoding="UTF-8"?>
<struts>
    <!-- Action mappings go here -->
</struts>

Hibernate Setup

• hibernate.cfg.xml can be omitted if configuration is merged into Spring config.
• Mapping files: *.hbm.xml placed alongside entity classes.

Spring Setup

web.xml

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:appContext.xml</param-value>
</context-param>

appContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
           http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:dbconfig.properties"/>

    <bean id="connPool" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${db.driver}"/>
        <property name="jdbcUrl" value="${db.url}"/>
        <property name="user" value="${db.user}"/>
        <property name="password" value="${db.pass}"/>
    </bean>

    <bean id="hibSessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <property name="dataSource" ref="connPool"/>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
        <property name="mappingResources">
            <list>
                <value>com/example/model/ItemEntity.hbm.xml</value>
            </list>
        </property>
    </bean>

    <bean id="itemAction" class="com.example.controller.ItemController">
        <property name="itemSvc" ref="itemSvc"/>
    </bean>

    <bean id="itemSvc" class="com.example.service.ItemService">
        <property name="itemDao" ref="itemDao"/>
    </bean>

    <bean id="itemDao" class="com.example.dao.ItemDao">
        <property name="sessionFactory" ref="hibSessionFactory"/>
    </bean>

    <bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory" ref="hibSessionFactory"/>
    </bean>

    <tx:annotation-driven transaction-manager="txManager"/>
</beans>

Package Structure and Entity Definition

Entity Class

package com.example.model;

public class ItemEntity implements java.io.Serializable {
    private int itemId;
    private String name;
    private double cost;

    public int getItemId() { return itemId; }
    public void setItemId(int itemId) { this.itemId = itemId; }

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

    public double getCost() { return cost; }
    public void setCost(double cost) { this.cost = cost; }
}

Example Flow: Adding an Item via Struts2 and Spring

Input Form (JSP)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="/struts-tags" prefix="sx" %>
<html>
<head><title>Add Item</title></head>
<body>
<h2>Create New Item</h2>
<sx:form action="item_add" method="post" theme="simple">
    | Name | <textfield name="name"></textfield> |
|---|---|
| Cost | <textfield name="cost"></textfield> |
| <submit value="Submit"></submit> |
</sx:form>
</body>
</html>

**Request Path:**Browser form → mapped in struts.xml to ItemController.add() → injected ItemService → delegated to ItemDao → persisted via Hibernate session.

Struts2 Action Mapping

<package name="webPkg" extends="struts-default">
    <action name="item_*" class="itemAction" method="{1}">
        <result name="ok">/index.jsp</result>
    </action>
</package>

ItemController Implementation

package com.example.controller;

import com.opensymphony.xwork2.*;
import com.example.model.ItemEntity;
import com.example.service.ItemService;

public class ItemController extends ActionSupport implements ModelDriven<ItemEntity> {
    private ItemEntity model = new ItemEntity();
    public ItemEntity getModel() { return model; }

    private ItemService itemSvc;
    public void setItemSvc(ItemService svc) { this.itemSvc = svc; }

    public String add() {
        System.out.println("Adding item...");
        itemSvc.save(model);
        return "ok";
    }
}

Service Layer

package com.example.service;

import com.example.model.ItemEntity;
import com.example.dao.ItemDao;

public class ItemService {
    private ItemDao dao;
    public void setDao(ItemDao d) { dao = d; }

    public void save(ItemEntity e) {
        dao.persist(e);
        System.out.println("Service saved item.");
    }
}

DAO Layer

package com.example.dao;

import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import com.example.model.ItemEntity;

public class ItemDao extends HibernateDaoSupport {
    public void persist(ItemEntity e) {
        System.out.println("DAO persisting item.");
        getHibernateTemplate().saveOrUpdate(e);
    }
}

Integrating Spring and Hibernate

Database Properties (dbconfig.properties)

db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/demoDb
db.user=root
db.pass=secret

Hibernate Mapping (ItemEntity.hbm.xml)

<?xml version="1.0" encoding="UTF-8"?>
<hibernate-mapping>
    <class name="com.example.model.ItemEntity" table="item_table">
        <id name="itemId" column="id">
            <generator class="native"/>
        </id>
        <property name="name" column="item_name"/>
        <property name="cost" column="item_cost"/>
    </class>
</hibernate-mapping>

With hibernate.hbm2ddl.auto set to update, the schema synchronizes automatically on application startup.