Explore the technical principles of Java -class library in ActiveJ: Inject framework

ActiveJ: Java -class library technical principle of inject framework ActiveJ: Inject is a lightweight dependency injection framework for building a Java application.It aims to simplify the organization and maintenance of code, and provide flexible dependency injection functions.This article will explore the technical principles of the ActiveJ: Inject framework and provide some Java code examples to illustrate its usage. I. Overview The core idea of the ActiveJ: Inject framework is to decouple the component of the application by injecting the dependency item.It uses a design mode called "reverse control", where the creation and management of dependency items transfer from the component itself to an independent container.This design mode allows application components to develop and test independently of its dependency items. Second, inject annotations ActiveJ: Inject provides some annotations to achieve the injection of dependencies.This includes: 1. @inject: Used to inject the specific implementation class into the component. 2. @Named: Used to specify a specific implementation class. When multiple implementation classes exist, they can be distinguished by names. 3. @eager: It is used to create instances immediately when the component initialization, rather than created when it is first used. 4. @Provides: The method for identifying the dependencies. 5. @module: Used to identify a class that provides dependency items. Third, the definition and use of components Below is a simple example that demonstrates how to use ActiveJ: Inject framework to achieve dependency injection: public interface UserService { void addUser(String username); } public class UserServiceImpl implements UserService { @Override public void addUser(String username) { System.out.println("User added: " + username); } } @Provides public UserService provideUserService() { return new UserServiceImpl(); } @Module public class AppModule { } public class MainClass { @Inject private UserService userService; public static void main(String[] args) { Injector injector = Injector.of(AppModule.class); MainClass mainClass = injector.getInstance(MainClass.class); mainClass.userService.addUser("John"); } } In the above examples, we first define a user service interface `useerservice`, and implement this method in the implementation class` userServiceImpl`. Then, we use the method to indicate a method that provides an instance that provides the `userService`, which returns an instance of` UserServiceImpl`.At the same time, we use the@module` annotation to identify the class `appmodule` containing the provided method. In the `MainClass` class, we injected` userService` into the `userService` field through the`@inject` annotation.Then, we use the instance of `mainClass` from the` Injector` class from the `appmodule`, and call the` adduser` method of `userService`. Fourth, summary ActiveJ: Inject framework provides a simple and powerful method to achieve dependency injection.Through annotations and containers, we can easily manage and inject dependencies to make the code more modular and testable.I hope this article will help you understand the technical principles of the ActiveJ: Inject framework and provide some guidance for your use of this framework in Java application development.