Spring Boot Framework Learning 2-spring boot core (1)

This section mainly:

1: Analysis of Spring boot Portal and @springbootapplication source detailed

Springbootapplication contains:

@SpringBootConfiguration

@ComponentScan

@EnableAutoConfiguration

This is the second Spring boot core (1) in the Edith Learning Series-Framework Learning Spring Boot Framework Study

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One: Spring boot entry and annotation parsing

In the previous chapter, we talked about the first spring boot application in the Portal:

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Description

Spring boot projects typically have *application entry classes, and the main method is in the entry class. This is the entry method for a standard Java application.

@controller: This annotation is spring. A declaration is a controller class.

@springBootApplication: This is Springboot's note.

Please see the source code for this class:

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From the source, we can see that this annotation is actually a set of combinations of annotations.

Let's take a look at @springbootconfiguration's note.

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From its source code, we can see that the note uses the @configuration annotation. So when using @springbootconfiguration annotations, you can not use @configuration annotations.

In fact, in the Springboot project to recommend the use of springbootconfiguration to replace @configuration annotations.

Come back and look at the springbootapplication annotation, which contains the @componentscan annotations.

@componentScan source code is as follows:

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@conponentScan: This annotation defaults to scanning the sibling directory of the @springbootapplication class and his subdirectories.

From the Componentscan source comments We can look at:

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Explanation of @EnableAutoConfiguration notes:

View source code and notes for this note:

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This annotation enables automatic configuration. From the source note we can tell that the comment will cause SPIRNG boot to automatically configure the project's configuration items based on the jar packages that are dependent on the project.

For example: We have configured spring-boot-starter-web dependencies in Pom.xml, and the project will introduce SPRINGMVC dependencies, and Spring boot will automatically configure Tomcat and SPRINGMVC. Spring boot is automatically configured as follows:

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Extended:

As we learned from the above, spring boot is automatically configured based on the project's Jar dependencies, and spring boot supports automatic configuration as follows (very many. Not all):

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From there we can see that many of our familiar things have been automatically configured.

Such as:

Batch processing framework Spring batch.

Cache caching

Spring Cloud

Spring JPA for data processing

MongoDB, neo4j, Redi, SOLR, etc.

If we want to, do not need spring boot automatic configuration, want to turn off the automatic configuration of an item, how to set it?

Welcome to the next article. We will answer in the next article.

Other articles in this series:

Spring Boot Framework Learn the important annotations of preschool mastery (1)-spring Java configuration method

Spring Boot Framework Learn important annotations for preschool Mastery (2)-Configure with Java configuration spring

Spring Boot Framework Learn important notes for preschool mastery (3)-read external resource profiles by annotation

Spring Boot Framework Learn important notes for preschool mastery (4)-read external resource profiles by annotation 2

Spring Boot Framework Learning 1-Understanding Spring boot and QuickStart

Spring Boot Framework Learning 2-spring boot core (1)

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Spring Boot Framework Learning 2-spring boot core (1)