Learn from the AUTOWIRE framework in the Java class library

Title: In -depth understanding of the autowire framework in the Java library introduce AUTOWIRE is a very important framework in the Java library that is used to realize the function of dependent injection.Dependent injection is a decoupling method that can improve the maintenance and testability of code.The AUTOWIRE framework enables us to give the dependencies between objects to the container to manage, thereby realizing a loose coupling design. The Autowire framework itself is a part of the Spring framework. It realizes the automatic injection function based on the reflection mechanism.When using the Autowire framework, we only need to use the annotation to mark it at the place where needed, and the framework will automatically inject the dependent objects into it. Common autowire injection method 1. Constructor Inject: Inject the objects relying on by the constructor. public class UserService { private UserRepository userRepository; public UserService(UserRepository userRepository) { this.userRepository = userRepository; } // ... } 2. Setter method injection (Setter Injection): Inject the dependent objects through the setter method. public class UserService { private UserRepository userRepository; public void setUserRepository(UserRepository userRepository) { this.userRepository = userRepository; } // ... } 3. Field Injection: Use annotations to mark directly on the field to inject the dependent objects into it. public class UserService { @Autowired private UserRepository userRepository; // ... } 4. Method inject: Inject the dependent objects through the method. public class UserService { private UserRepository userRepository; @Autowired public void setUserRepository(UserRepository userRepository) { this.userRepository = userRepository; } // ... } Use of autowire annotation To use the Autowire framework, we need to use the @Autowired annotation where we need to inject.The Autowire framework will automatically scan these annotations and inject the corresponding dependencies into it. public class UserController { @Autowired private UserService userService; // ... } In the above example, the AUTOWIRE framework will automatically inject the UserService object into the UserService field in the UserController class. Autowire framework and Spring framework The Autowire framework is part of the Spring framework, which provides a function of relying in injection.When using the Spring framework, we can manage the dependencies between objects through the autowire framework to achieve loose coupling design. In addition to the common AUTOWIRE injection method mentioned above, the Spring framework also provides other special injection methods, such as the injecting constructor injection, annotated field injection, etc. summary The Autowire framework is a very important framework in the Java library. It enables us to achieve loose coupling design by relying on the injection function.When using the Autowire framework, we can choose different injection methods, such as constructor injection, setter method injection, field injection, and method injection.At the same time, the Autowire framework is also part of the Spring framework, which can help us manage the dependent relationship between objects. I hope that this article can help you better understand and use the Autowire framework, and improve the maintenance and testability of code when developing Java applications.