What is the loading process of Spring Boot?
The loading process of Spring Boot can be divided into the following steps:
- Scan the dependencies and classpath of the project, including both the project itself and all imported dependencies.
- Using the agreed-upon rules, Spring Boot automatically configures various functions such as creating a database connection pool and configuring a transaction manager. These automatic configurations are implemented by using Spring Boot’s starter modules, which are dependencies that provide specific functionalities.
- Override or supplement the default values of auto-configuration based on the configuration information in the settings file (application.properties or application.yml). Configuration in the file can be used to customize properties such as the URL, username, and password for database connection.
- Create a Spring application context and load all bean definitions. The Spring application context is the core container of the Spring framework, responsible for managing the creation, initialization, and destruction of beans.
- Performing lifecycle callbacks for various Beans, such as executing methods annotated with @PostConstruct and registering Bean post processors.
- Start the Spring application. This step will start the embedded Tomcat server and deploy the Spring application context to the Tomcat server.
- Spring Boot simplifies the configuration of Spring MVC by automatically handling HTTP requests and invoking the corresponding Controller method based on the request URL and HTTP method.
- Handling HTTP responses involves automatically generating the HTTP response based on the return value of the Controller method. By default, Spring Boot uses JSON format for data exchange, but you can customize the response format through configuration files.
Overall, the loading process of Spring Boot is mainly simplified through the principles of automatic configuration and convention over configuration to streamline the development and deployment of Spring applications. Developers only need to add dependencies and configure some properties, in order to quickly build a fully functional Spring application.
