What is the spring startup process?

spring startup process: 1. Load the configuration file; 2. Instantiate the Bean container; 3. Register the Bean; 4. Dependency injection; 5. Initialize the Bean; 6. Configuration event publishing; 7. Application context startup; 8. Request processing; 9. Response return; 10. Closing and cleaning. Detailed introduction: 1. Load the configuration file. The startup of the Spring application starts with loading the configuration file. The configuration file is usually an XML file, but it can also be a JavaConfig class or annotation configuration; 2. Instantiate the Bean container, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

The startup process of the Spring framework mainly involves the following key steps:

1. Load the configuration file:

• Spring application Startup starts by loading the configuration file. The configuration file is usually an XML file, but can also be a JavaConfig class or annotation configuration. In this file, the developer defines the beans and their dependencies.

2. Instantiate the Bean container:

• After the configuration file is loaded, Spring will create a Bean container instance. This container is responsible for managing beans in the application. It is responsible for parsing configuration information, creating and initializing beans.

3. Register Bean:

• The Bean container will traverse the configuration file, parse each element, and create a corresponding bean instance. Each bean can be viewed as a Java object with corresponding properties and methods.

4. Dependency injection:

• After registering the bean, Spring will automatically handle dependency injection. Through the autowiring mechanism, Spring will automatically inject the dependencies of one bean into another bean. This is achieved through setter injection, constructor injection or field injection. Developers only need to use the @Autowired annotation on the corresponding properties.

5. Initialize Beans:

• After all beans are registered and dependencies are resolved, the bean container will follow the order of the configuration file (or Initialize these beans through other strategies). This means that beans that depend on other beans will be initialized after the beans they depend on are initialized.

6. Configuration event publishing:

• During the bean initialization process, Spring will publish a series of events, such as ContextRefreshedEvent, ContextStartedEvent, etc. These events allow developers to perform custom operations, such as monitoring, interception, etc., when the Spring container is initialized or running.

7. Application context startup:

• Once all beans have been initialized and related configuration events have been published, the Spring container (i.e. application context) to announce that the startup is complete. This means that the application is ready to receive requests or perform other tasks.

8. Request processing:

• When the application starts and is ready to receive a request, it will process the request according to the type of the request ( Such as HTTP requests) and routing rules distribute the request to the appropriate processor or controller. These handlers or controllers are typically developer-defined beans that handle business logic and return responses.

9. Response return:

• After the processor or controller processes the request, it will return a response to caller. This response can be an HTML page, JSON data, or data in other formats.

10. Shutdown and cleanup:

• When the application no longer needs to run, Spring will execute the shutdown process . This includes destroying all bean instances, cleaning up resources, publishing shutdown events, etc. This step ensures that the application does not leave any resource leaks or unfinished operations when it is closed.

In summary, Spring's startup process involves loading configuration files, creating bean containers, registering and initializing beans, processing dependency injection, publishing configuration events, application context startup, processing requests, returning responses, and closing Cleaning and other steps. This process ensures that Spring applications initialize and run correctly and provides developers with flexibility and scalability.

The above is the detailed content of What is the spring startup process?. For more information, please follow other related articles on the PHP Chinese website!