How to implement inversion of control in Spring?

In Spring, Inversion of Control (IoC) is achieved through Dependency Injection (DI). Here are the steps to implement Inversion of Control.

1. To create a Spring configuration file, first you need to create a file to define and configure the lifecycle and dependency relationships of the beans.
2. Bean declaration: In Spring configuration files, Beans are declared by using the element, indicating objects that need to be managed by the container. Beans can be created by specifying the fully qualified name of a class or by referencing other Beans.
3. Configuring dependencies: Utilizing elements to configure the dependencies between Beans. Dependencies can be injected by directly setting property values or by referencing other Beans.
4. Creating a Spring container: In an application, a Spring container is created to load and manage beans. Different types of containers can be chosen, such as ClassPathXmlApplicationContext, AnnotationConfigApplicationContext, etc.
5. Accessing Beans: Obtain an instance of a Bean by using its unique identifier within the Spring container. Beans can be accessed by using the getBean() method of the container.
6. Using Beans: In an application, you can call methods or access properties of the obtained Bean instances.

By following these steps, Spring has achieved inversion of control, delegating the creation and management of objects to the container. Applications only need to retrieve the required instances from the container, thereby achieving decoupling and flexibility.