Introduction

Integrating JSP and Servlets with Hibernate allows for a clean separation of the presentation layer and the data access layer. Hibernate handles the database operations, while JSPs and Servlets manage the user interface and request handling. In this tutorial, we will:

1. Set up a Maven project with necessary dependencies.
2. Configure Hibernate and MySQL.
3. Create an entity class (User).
4. Create JSPs for the login interface.
5. Implement Servlets for handling login requests.
6. Use annotations instead of web.xml for configuration.

Step 1: Set Up Your Project

1.1 Create a Maven Project

Open your IDE and create a new Maven project.

1.2 Add Dependencies

Update your pom.xml file to include dependencies for Hibernate, MySQL, JSP, and Servlet API.

<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>com.example</groupId>
    <artifactId>login-example</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- Hibernate ORM -->
        <dependency>
            <groupId>org.hibernate.orm</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>6.4.0.Final</version>
        </dependency>

        <!-- MySQL Connector -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.29</version>
        </dependency>

        <!-- Servlet API -->
        <dependency>
            <groupId>jakarta.servlet</groupId>
            <artifactId>jakarta.servlet-api</artifactId>
            <version>6.0.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- JSP API -->
        <dependency>
            <groupId>jakarta.servlet.jsp</groupId>
            <artifactId>jakarta.servlet.jsp-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

        <!-- JSTL -->
        <dependency>
            <groupId>jakarta.servlet.jsp.jstl</groupId>
            <artifactId>jakarta.servlet.jsp.jstl-api</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.web</groupId>
            <artifactId>jakarta.servlet.jsp.jstl</artifactId>
            <version>2.0.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.10.1</version>
                <configuration>
                    <source>21</source>
                    <target>21</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Step 2: Configure Hibernate

2.1 Create hibernate.cfg.xml

Create a hibernate.cfg.xml file in the src/main/resources directory to configure database connection settings and Hibernate properties.

<!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.dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hibernate_db</property>
        <property name="hibernate.connection.username">root</property>
        <property name="hibernate.connection.password">password</property>
        <property name="hibernate.hbm2ddl.auto">update</property>
        <property name="hibernate.show_sql">true</property>
    </session-factory>
</hibernate-configuration>

Replace hibernate_db, root, and password with your MySQL database name and credentials.

Explanation:

• hibernate.dialect specifies the SQL dialect to be used.
• hibernate.connection.driver_class specifies the JDBC driver class.
• hibernate.connection.url specifies the JDBC URL for the database connection.
• hibernate.connection.username and hibernate.connection.password specify the database credentials.
• hibernate.hbm2ddl.auto specifies the schema generation strategy.
• hibernate.show_sql specifies whether to show SQL statements in the logs.

Step 3: Create the Entity Class

Create an entity class User that will be mapped to a table in the database. This class uses annotations to define the entity and its fields.

package com.example.entity;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;

    // Getters and setters
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

Explanation:

• The @Entity annotation specifies that the class is an entity and is mapped to a database table.
• The @Id annotation specifies the primary key of the entity.
• The @GeneratedValue(strategy = GenerationType.IDENTITY) annotation specifies that the primary key is auto-incremented.

Step 4: Create JSPs for User Interface

Create a JSP file named index.jsp in the src/main/webapp directory to provide the login form.

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <title>Login Page</title>
</head>
<body>
    <h1>Login</h1>
    <form action="loginServlet" method="post">
        <label for="username">Username:</label>
        <input type="text" id="username" name="username"><br><br>
        <label for="password">Password:</label>
        <input type="password" id="password" name="password"><br><br>
        <input type="submit" value="Login">
    </form>
    <p>${message}</p>
</body>
</html>

Create a welcome.jsp to display a welcome message upon successful login.

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
    <title>Welcome</title>
</head>
<body>
    <h1>Welcome, ${username}!</h1>
</body>
</html>

Explanation:

• index.jsp provides a form to collect user credentials.
• welcome.jsp displays a welcome message for the logged-in user.

Step 5: Implement Servlet for Handling Login Requests

Create a servlet named LoginServlet to handle login requests.

5.1 Create LoginServlet

package com.example.servlet;

import com.example.entity.User;
import com.example.util.HibernateUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.hibernate.Session;

import java.io.IOException;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        Session session = HibernateUtil.getSessionFactory().openSession();
        User user = (User) session.createQuery("FROM User WHERE username = :username AND password = :password")
                                  .setParameter("username", username)
                                  .setParameter("password", password)
                                  .uniqueResult();

        session.close();

        if (user != null) {
            request.setAttribute("username", user.getUsername());
            request.getRequestDispatcher("welcome.jsp").forward(request, response);
        } else {
            request.setAttribute("message", "Invalid username or password");
            request.getRequestDispatcher("index.jsp").forward(request, response);
        }
    }
}

Explanation:

• The LoginServlet class handles POST requests to authenticate the user using Hibernate and redirect to the appropriate JSP page based on the authentication result.

Step 6: Configure Hibernate Utility Class

Create a

utility class HibernateUtil to manage the Hibernate SessionFactory.

package com.example.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {
    private static final SessionFactory sessionFactory = buildSessionFactory();

    private static SessionFactory buildSessionFactory() {
        try {
            return new Configuration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    public static void shutdown() {
        getSessionFactory().close();
    }
}

Explanation:

• The HibernateUtil class provides a singleton SessionFactory and a method to shut it down.

Step 7: Run the Application

1. Deploy the application to a servlet container like Apache Tomcat.
2. Access the application at http://localhost:8080/login-example/.
3. Use the login form to enter user credentials and test the login functionality.

Sample Output

When you log in with valid credentials, you should be redirected to welcome.jsp displaying a welcome message. If the credentials are invalid, you should see an error message on the index.jsp.

Conclusion

In this tutorial, we have successfully set up a JSP Servlet Hibernate web application using a MySQL database and the User entity. We configured the project dependencies, Hibernate, created an entity class, implemented a servlet to handle login requests, and demonstrated the use of JSPs to create a login interface. This guide provides a solid foundation for building a web application with JSP, Servlets, and Hibernate, allowing you to extend the application further as needed.