Java EE Development Technology and Tutorial with Real-World Examples294

Java Enterprise Edition (Java EE) is a platform for developing large-scale, enterprise-grade applications. It provides a comprehensive set of APIs and frameworks that can be used to build complex applications in a modular and scalable way. In this tutorial, we will explore the key concepts and technologies involved in Java EE development, and we will build a simple web application as an example.

Java EE Architecture

Java EE is a multi-tiered architecture, which means that applications are typically divided into multiple layers, each with its own set of responsibilities. The main tiers in a Java EE application are:
Presentation tier: This tier contains the user interface of the application. It is responsible for rendering pages and handling user input.
Business tier: This tier contains the business logic of the application. It is responsible for processing data and making decisions.
Persistence tier: This tier is responsible for storing and retrieving data.

Java EE Technologies

Java EE provides a wide range of technologies that can be used to build applications. Some of the most important technologies include:
JavaServer Faces (JSF): A framework for building web applications.
Java Persistence API (JPA): An API for object-relational mapping.
Enterprise JavaBeans (EJB): A framework for developing business logic.
Java Message Service (JMS): An API for messaging.
Java Transaction API (JTA): An API for managing transactions.

Building a Java EE Application

Now that we have a basic understanding of Java EE, let's build a simple web application. We will use JSF for the presentation tier, JPA for the persistence tier, and EJB for the business tier.

Step 1: Create a new Java EE project

Open your Java IDE and create a new Java EE project. Select the "Web Application" project type and give it a name.

Step 2: Add the necessary libraries

Add the following libraries to your project:```xml


jsf-api
2.3.25



jsf-impl
2.3.25



-api
2.2



hibernate-jpa-2.1-api




ejb-api
3.2

```

Step 3: Create the entity class

Create a new class called `Product`. This class will represent the products in our database.```java
@Entity
@Table(name = "products")
public class Product {
@Id
@GeneratedValue(strategy = )
private int id;
private String name;
private double price;
}
```

Step 4: Create the DAO class

Create a new class called `ProductDAO`. This class will contain the methods for interacting with the database.```java
public class ProductDAO {
@PersistenceContext
private EntityManager em;
public void create(Product product) {
(product);
}
public Product find(int id) {
return (, id);
}
public List findAll() {
return ("from Product", ).getResultList();
}
public void update(Product product) {
(product);
}
public void delete(Product product) {
(product);
}
}
```

Step 5: Create the EJB class

Create a new class called `ProductService`. This class will contain the business logic for our application.```java
@Stateless
public class ProductService {
@Inject
private ProductDAO productDAO;
public void create(Product product) {
(product);
}
public Product find(int id) {
return (id);
}
public List findAll() {
return ();
}
public void update(Product product) {
(product);
}
public void delete(Product product) {
(product);
}
}
```

Step 6: Create the JSF page

Create a new JSF page called ``. This page will contain the user interface for our application.```xhtml



Products










```

Step 7: Run the application

Run the application in your Java IDE. The application should display a list of products.

Conclusion

In this tutorial, we have explored the key concepts and technologies involved in Java EE development, and we have built a simple web application as an example. Java EE is a powerful platform for developing large-scale, enterprise-grade applications, and it can be used to build a wide range of applications, from simple web applications to complex business systems.

2025-02-16

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