Struts2 Hibernate Integration Example Tutorial

Struts2 and Hibernate both are widely used frameworks in their respective area. Today we will learn how to integrate Struts2 Web application framework with Hibernate ORM framework.

Unlike Spring Hibernate Integration, there are no plugins provided by Struts2 framework that we can use, so we would need to use the Servlet Listener to manage the Hibernate SessionFactory. Let’s see how to do this with a simple web application example.

Our final project structure will look like below image, we will look into each of the component one by one. Start with creating a “Dynamic Web Project” in Eclipse and then convert it to maven project to get the basic skeleton ready for our web application.

Database Setup

We will create a login application, after authentication user will be present to the welcome page where all his information will be displayed. Below SQL script will create the required table and insert data that we will use for authentication.

Struts2, Hibernate and MySQL Dependencies

We need to add Struts2, Hibernate and MySQL dependencies in pom.xml file, final pom.xml file looks like below.

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>Struts2Hibernate</groupId>
  <artifactId>Struts2Hibernate</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
   
    <dependencies>
    <dependency>
        <groupId>org.apache.struts</groupId>
        <artifactId>struts2-core</artifactId>
        <version>2.3.15.1</version>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.3.5.Final</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.0.5</version>
    </dependency>
  </dependencies>
   
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>2.3</version>
        <configuration>
          <warSourceDirectory>WebContent</warSourceDirectory>
          <failOnMissingWebXml>false</failOnMissingWebXml>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.7</source>
          <target>1.7</target>
        </configuration>
      </plugin>
    </plugins>
    <finalName>${project.artifactId}</finalName>
  </build>
 
</project>

We are using Hibernate 4 for our example, however same code will work with Hibernate 3 too. Although you might need to do some configuration hibernate 3 specific changes.

Deployment Descriptor

We need to plugin Struts2 framework in our web application by applying StrutsPrepareAndExecuteFilter in deployment descriptor.

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" 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>Struts2Hibernate</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.journaldev.struts2hibernate.listener.HibernateServletContextListener</listener-class>
    </listener>
</web-app>

Notice that HibernateServletContextListener will be used to manage Hibernate SessionFactory, we will look it’s code later on.

Entity Bean

Our entity bean will also work as the struts2 action class model bean, it looks like below.

User.java

package com.journaldev.struts2hibernate.model;
 
public class User {
 
    private String id;
    private String name;
    private String pwd;
    private String email;
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public String getPwd() {
        return pwd;
    }
 
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
 
    public String getEmail() {
        return email;
    }
 
    public void setEmail(String email) {
        this.email = email;
    }
 
    public String getId() {
        return id;
    }
 
    public void setId(String id) {
        this.id = id;
    }
     
    @Override
    public String toString(){
        return "Name= "+name+", Email= "+email;
    }
}

I am using XML based mappings, but we can also use JPA annotations based mapping for our entity bean.

Hibernate DAO Implementation Classes

Our UserDAO interface declares the method that will be exposed for User entity bean.

UserDAO.java

package com.journaldev.struts2hibernate.dao;
 
import com.journaldev.struts2hibernate.model.User;
 
public interface UserDAO {
 
    User getUserByCredentials(String userId, String password);
}

Hibernate specific DAO implementation looks like below.

UserDAOImpl.java

package com.journaldev.struts2hibernate.dao;
 
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
 
import com.journaldev.struts2hibernate.model.User;
 
public class UserDAOImpl implements UserDAO {
     
    private SessionFactory sf;
     
    public UserDAOImpl(SessionFactory sf){
        this.sf = sf;
    }
 
    @Override
    public User getUserByCredentials(String userId, String password) {
        Session session = sf.openSession();
        Transaction tx = session.beginTransaction();
        Query query = session.createQuery("from User where id=:id and pwd=:pwd");
        query.setString("id", userId); query.setString("pwd", password);
        User user = (User) query.uniqueResult();
        if(user != null){
            System.out.println("User Retrieved from DB::"+user);
        }
        tx.commit();session.close();
        return user;
    }
 
}

Servlet Context Listener

We will initialize Hibernate SessionFactory in the ServletContextListener implementation, when application will be stopped, we will destroy the SessionFactory.

HibernateServletContextListener.java

package com.journaldev.struts2hibernate.listener;
 
import java.net.URL;
 
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
 
import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
 
public class HibernateServletContextListener implements ServletContextListener {
 
    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        SessionFactory sf = (SessionFactory) sce.getServletContext().getAttribute("SessionFactory");
        sf.close();
    }
 
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        URL url = HibernateServletContextListener.class.getResource("/hibernate.cfg.xml");
        Configuration config = new Configuration();
        config.configure(url);
        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                        .applySettings(config.getProperties()).build();
        SessionFactory sf = config.buildSessionFactory(serviceRegistry);
        sce.getServletContext().setAttribute("SessionFactory", sf);
    }
 
}

Action Class

Our hibernate specific setup is ready, let’s move on to Struts2 action class.

LoginAction.java

package com.journaldev.struts2hibernate.action;
 
import javax.servlet.ServletContext;
 
import org.apache.struts2.util.ServletContextAware;
import org.hibernate.SessionFactory;
 
import com.journaldev.struts2hibernate.dao.UserDAO;
import com.journaldev.struts2hibernate.dao.UserDAOImpl;
import com.journaldev.struts2hibernate.model.User;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ModelDriven;
 
public class LoginAction implements Action, ModelDriven<User>, ServletContextAware {
     
    @Override
    public String execute() throws Exception {
         
        SessionFactory sf = (SessionFactory) ctx.getAttribute("SessionFactory");
        UserDAO userDAO = new UserDAOImpl(sf);
        User userDB = userDAO.getUserByCredentials(user.getId(), user.getPwd());
        if(userDB == null) return ERROR;
        else {
            user.setEmail(userDB.getEmail());
            user.setName(userDB.getName());
            return SUCCESS;
        }
    }
 
    @Override
    public User getModel() {
        return user;
    }
     
    private User user = new User();
     
    private ServletContext ctx;
 
    @Override
    public void setServletContext(ServletContext sc) {
        this.ctx = sc;
    }
     
}

Struts2, Hibernate Configuration and Hibernate Mapping XML

We have following URI configurations in Struts2 configuration file.

struts.xml

<?xml version="1.0" encoding="UTF-8"?>
 
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.devMode" value="true"></constant>
 
<constant name="struts.convention.result.path" value="/"></constant>
 
<package name="user" namespace="/User" extends="struts-default">
    <action name="home">
        <result>/login.jsp</result>
    </action>
    <action name="login" class="com.journaldev.struts2hibernate.action.LoginAction">
    <result name="success">/welcome.jsp</result>
    <result name="error">/error.jsp</result>
    </action>
 
</package>
 
</struts>

Hibernate Configuration File looks like below.

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- Database connection properties - Driver, URL, user, password -->
        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost/TestDB</property>
        <property name="hibernate.connection.username">pankaj</property>
        <property name="hibernate.connection.password">pankaj123</property>
        <!-- Connection Pool Size -->
        <property name="hibernate.connection.pool_size">1</property>
         
        <!-- org.hibernate.HibernateException: No CurrentSessionContext configured! -->
        <property name="hibernate.current_session_context_class">thread</property>
         
        <!-- Disable the second-level cache -->
        <property name="hibernate.cache.provider_class">org.hibernate.cache.internal.NoCacheProvider</property>
        <!-- Outputs the SQL queries, should be disabled in Production -->
        <property name="hibernate.show_sql">true</property>
         
        <!-- Dialect is required to let Hibernate know the Database Type, MySQL, Oracle etc
            Hibernate 4 automatically figure out Dialect from Database Connection Metadata -->
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
 
        <!-- mapping file, we can use Bean annotations too -->
        <mapping resource="User.hbm.xml" />
    </session-factory>
</hibernate-configuration>

Hibernate Mapping XML file looks like below.

User.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="com.journaldev.struts2hibernate.model.User" table="USER">
        <id name="id" type="java.lang.String">
            <column name="USER_ID" />
            <generator class="assigned" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" />
        </property>
        <property name="pwd" type="java.lang.String">
            <column name="PASSWORD" />
        </property>
        <property name="email" type="java.lang.String">
            <column name="EMAIL" />
        </property>
    </class>
</hibernate-mapping>

View Pages

As you can see from struts2 configuration file, we have three view pages. They are simple pages and looks like below.

login.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
    pageEncoding="US-ASCII"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%-- Using Struts2 Tags in JSP --%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>Login Page</title>
</head>
<body>
<h3>Welcome User, please login below</h3>
<s:form action="login">
    <s:textfield name="id" label="User ID"></s:textfield>
    <s:textfield name="pwd" label="Password" type="password"></s:textfield>
    <s:submit value="Login"></s:submit>
</s:form>
</body>
</html>

welcome.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
    pageEncoding="US-ASCII"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!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=US-ASCII">
<title>Welcome Page</title>
</head>
<body>
<h3>Welcome <s:property value="name"></s:property></h3>
 
<h3>Your id is <s:property value="id"></s:property></h3>
 
<h3>Your password is <s:property value="pwd"></s:property></h3>
 
<h3>Your email id is <s:property value="email"></s:property></h3>
 
</body>
</html>

error.jsp

<%@ page language="java" contentType="text/html; charset=US-ASCII"
    pageEncoding="US-ASCII"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
     
<!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=US-ASCII">
<title>Error Page</title>
</head>
<body>
<h4>User Name or Password is wrong</h4>
<s:include value="login.jsp"></s:include>
</body>
</html>

Struts2 Hibernate Application Test

Our application is ready, build and deploy it into your favorite servlet container and you should get response pages like below images.

Struts2 Hibernate Login Page

Struts2 Hibernate Welcome Page

Struts2 Hibernate Login Error Page

You will also notice hibernate queries and other logs in the server log file.

Hibernate: select user0_.USER_ID as USER_ID1_0_, user0_.NAME as NAME2_0_, user0_.PASSWORD as PASSWORD3_0_, user0_.EMAIL as EMAIL4_0_ from USER user0_ where user0_.USER_ID=? and user0_.PASSWORD=?
User Retrieved from DB::Name= Pankaj Kumar, Email= pankaj@journaldev.com

Struts2 Hibernate Integration Summary

This tutorial was aimed to provide details about Struts2 and Hibernate integration, so that you can get started. As you can see that Servlet Context Listener makes it very easy to integrate. You can download the final project from below link.