How to integrate Hibernate with Struts 2x ?

STEPS

1. Register a custom ServletContextListener.

2. In the ServletContextListener class, initialize the Hibernate session and store it into the servlet context.

3. In action class, get the Hibernate session from the servlet context, and perform the Hibernate task as normal.

Relationship

Struts 2 ---- (Servlet Context) ---- Hibernate ----- Database

A simple customer module (add and list function), developed in Struts 2, and perform the database operation with Hibernate.

The integration part is using the above stated mechanism (store and retrieve the Hibernate session in the servlet context).

This workaround is very similar with the classic Struts 1.x and Hibernate integration, just the classic Struts 1.x is using the Struts’s plugins; While the Struts 2 is using the generic servlet listener.

Dependency libraries (for Struts2, Hibernate and MySQL)

• Struts 2 = struts2-core 2.1.8
• MySQL database driver = mysql-connector-java 5.1.9
• Hibernate core = hibernate 3.2.7.ga
• Hibernate core library dependency = dom4j 1.6.1, commons-logging 1.1.1,
                                                             commons-collections 3.2.1, cglib 2.2
• Hibernate query library dependency = antlr 2.7.7

Hibernate Stuffs

The Hibernate model and configuration stuffs.

Customer.java – Create a class for customer table.

package com.genius.customer.model;

import java.util.Date;

public class Customer implements java.io.Serializable {

  private Long customerId;

  private String name;

  private String address;

  private Date createdDate;

  // getter and setter methods

}

Customer.hbm.xml – Hibernate mapping file for customer.

<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping 

 DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="com.genius.customer.model.Customer" table="customer" catalog="shaan">

   <id name="customerId" type="java.lang.Long">

     <column name="CUSTOMER_ID" />

     <generator class="identity" />

   </id>

   <property name="name" type="string">

      <column name="NAME" length="45" not-null="true" />

   </property>

   <property name="address" type="string">

      <column name="ADDRESS" not-null="true" />

   </property>

   <property name="createdDate" type="timestamp">

     <column name="CREATED_DATE" length="19" not-null="true" />

   </property>

</class>

</hibernate-mapping>

hibernate.cfg.xml – Hibernate database configuration file.

<?xml version="1.0" encoding="utf-8"?>

<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

  <session-factory>

     <property name="hibernate.bytecode.use_reflection_optimizer">false</property>

     <property name="hibernate.connection.password">password</property>

     <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/genius</property>

     <property name="hibernate.connection.username">root</property>

     <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>

     <property name="show_sql">true</property>

     <property name="format_sql">true</property>

     <property name="use_sql_comments">false</property>

     <mapping resource="com/genius/customer/hibernate/Customer.hbm.xml" />

  </session-factory>

</hibernate-configuration>

Hibernate Listner

Hibernate ServletContextListener

Create a ServletContextListener, and initialize the Hibernate session and store it into the servlet context.

HibernateListener .java

package com.genius.listener;

import java.net.URL;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

public class HibernateListener implements ServletContextListener{

  private Configuration config;

  private SessionFactory factory;

  private String path = "/hibernate.cfg.xml";

  private static Class clazz = HibernateListener.class;

  public static final String KEY_NAME = clazz.getName();

  public void contextDestroyed(ServletContextEvent event) {

     // ....

  }

  public void contextInitialized(ServletContextEvent event) {

    try {

       URL url = HibernateListener.class.getResource(path);

       config = new Configuration().configure(url);

       factory = config.buildSessionFactory();

       // save the Hibernate session factory into serlvet context

       event.getServletContext().setAttribute(KEY_NAME, factory);

   } catch (Exception e) {

       System.out.println(e.getMessage());

  }

 }  }

Register the listener in the web.xml file

web.xml

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

<display-name>Struts 2 Web Application</display-name>

<filter>

  <filter-name>struts2</filter-name>

  <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>

</filter>

<filter-mapping>

  <filter-name>struts2</filter-name>

  <url-pattern>/*</url-pattern>

</filter-mapping>

<listener>

  <listener-class>com.genius.listener.HibernateListener</listener-class>

</listener>

</web-app>

Struts 2 stuff

Action

In Action class, get the Hibernate session from the servlet context and perform the Hibernate task as normal.

CustomerAction.java

package com.genius.customer.action;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import org.apache.struts2.ServletActionContext;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import com.shaan.customer.model.Customer;

import com.shaan.listener.HibernateListener;

import com.opensymphony.xwork2.ActionSupport;

import com.opensymphony.xwork2.ModelDriven;

public class CustomerAction extends ActionSupport implements ModelDriven {

  Customer customer = new Customer();

  List<Customer> customerList = new ArrayList<Customer>();

  public String execute() throws Exception {

    return SUCCESS;

  }

  public Object getModel() {

    return customer;

  }

  public List<Customer> getCustomerList() {

    return customerList;

  }

  public void setCustomerList(List<Customer> customerList) {

    this.customerList = customerList;

  }

  // save customer

  public String addCustomer() throws Exception{

    // get hibernate session from the servlet context

    SessionFactory sessionFactory = (SessionFactory) ServletActionContext

      .getServletContext().getAttribute(HibernateListener.KEY_NAME);

    Session session = sessionFactory.openSession();

    // save it

    customer.setCreatedDate(new Date());

    session.beginTransaction();

    session.save(customer);

    session.getTransaction().commit();

    // reload the customer list

    customerList = null;

    customerList = session.createQuery("from Customer").list();

    return SUCCESS;

  }

  // list all customers

  public String listCustomer() throws Exception{

    // get hibernate session from the servlet context

    SessionFactory sessionFactory = (SessionFactory)ServletActionContext.getServletContext().getAttribute(HibernateListener.KEY_NAME);

    Session session = sessionFactory.openSession();

    customerList = session.createQuery("from Customer").list();

    return SUCCESS;

  }

}

JSP page

JSP page to add and list the customer.

customer.jsp

<%@ taglib prefix="s" uri="/struts-tags" %>

<html>

<head></head>

<body>

<h1>Struts 2 + Hibernate integration example</h1>

<h2>Add Customer</h2>

<s:form action="addCustomerAction" >

<s:textfield name="name" label="Name" value="" />

<s:textarea name="address" label="Address" value="" cols="50" rows="5" />

<s:submit />

</s:form>

<h2>All Customers</h2>

<s:if test="customerList.size() > 0">

  <table border="1px" cellpadding="8px">

  <tr>

   <th>Customer Id</th>

   <th>Name</th>

   <th>Address</th>

   <th>Created Date</th>

  </tr>

 <s:iterator value = "customerList" status="userStatus">

  <tr>

   <td><s:property value="customerId" /></td>

   <td><s:property value="name" /></td>

   <td><s:property value="address" /></td>

   <td><s:date name="createdDate" format="dd/MM/yyyy" /></td>

  </tr>

 </s:iterator>

</table>

</s:if>

</body>

</html>

Entries in 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.devMode" value="true" />

<package name="default" namespace="/" extends="struts-default">

<action name="addCustomerAction" class="com.genius.customer.action.CustomerAction" method="addCustomer" >

  <result name="success">pages/customer.jsp</result>

</action>

<action name="listCustomerAction" class="com.genius.customer.action.CustomerAction" method="listCustomer" >

  <result name="success">pages/customer.jsp</result>

</action>

</package>

</struts>

Reference