Use CDI API to improve the efficiency of project development

Use CDI API to improve the efficiency of project development CDI (Contexts and Dependency Injection) is a core specification of Java EE. It provides a flexible and scalable dependency injection mechanism that can significantly improve the development efficiency and maintenance of enterprise applications.In this article, we will explore how to use CDI API to accelerate the development of the project. 1. Dependent injection The main function of CDI is to provide a dependent injection mechanism, which can automatically inject the dependent relationship into the place where the need.By using @inject annotations, we can inject the dependent objects into the target class without manual creation and management object instances.This method follows the principle of opening and closing, making the code clearer and maintainable. The following is an example that demonstrates how to use CDI's dependency injection: public class OrderService { @Inject private CustomerService customerService; // ... } In the above example, the Orderservice class uses @inject annotations to inject Customerservice into it.In this way, when using the OrderService, we do not need to manually create an instance of Customerservice, and CDI will automatically inject an available instance. 2. Life cycle management The CDI provides support for the life cycle management of the instance, which can ensure that each instance is reasonably created, destroyed and recycled.By using@ApplicationScoped,@RequestScoped,@SESSIONSCOPED, etc., we can associate the life cycle of the instance with different parts of the application. The following is an example that demonstrates how to use the CDI's life cycle management: @ApplicationScoped public class OrderRepository { // ... } // ... @RequestScoped public class OrderService { @Inject private OrderRepository orderRepository; // ... } In the above example, OrderRePOSITORY is annotated as @ApplicationScoped, indicating that its instance is created only once during the life cycle of the application.Orderservice is annotated as @RequestScoped, indicating that its instance will be created once in each HTTP request. 3. Event release and observation CDI provides an event system that can be published and observed between different components to decouple and communicate between modules. The following is an example that demonstrates how to use the CDI incident release and observation: public class OrderService { @Inject private Event<OrderEvent> event; public void createOrder() { // Create order logic ... // Release order events event.fire(new OrderEvent(order)); } } // ... public class OrderEventHandler { public void onOrderCreated(@Observes OrderEvent event) { // Treatment of order creation events } } In the above example, OrderService injected an Event <Orderevent> object to publish an order event through the @Inject annotation.And the Ordereventhandler class uses @ObServes annotations to listen to the Orderevent event. Once a new order event is released, it will automatically trigger the corresponding processing logic. By using the CDI event system, we can easily realize the decoupling and flexible message transmission of business logic. Summarize: The CDI API provides many powerful functions to improve the development efficiency of the project.By relying on injection, life cycle management, and event release and observation, we can better organize code to improve maintenance and scalability.I hope that the techniques introduced in this article can help you better use CDI API to develop efficient and maintained corporate applications.