@SpringBootApplication 之 @SpringBootConfiguration

原创转载请注明出处：https://www.cnblogs.com/agilestyle/p/14900455.html

 

@SpringBootApplication 是一个复合注解，包括

• @SpringBootConfiguration
• @EnableAutoConfiguration
• @ComponentScan

 

@SpringBootConfiguration 源码

可以看出@SpringBootConfiguration 其实就是一个 @Configuration，标注当前类是配置类。

从Spring3.0开始，@Configuration 用于定义配置类，可替换xml 配置文件，被注解的类内部包含一个或多个@Bean 注解的方法，这些方法将会被AnnotationConfigApplicationContext 或AnnotationConfigWebApplicationContext 类进行扫描，并且构建bean 定义，初始化Spring 容器。

@Configuration 标注在类上，等价于Spring 的xml 配置文件中的 <beans></beans>

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="..." class="...">  
        <!-- collaborators and configuration for this bean go here -->
    </bean>

    <bean id="..." class="...">
        <!-- collaborators and configuration for this bean go here -->
    </bean>

    <!-- more bean definitions go here -->

</beans>

 

使用@Configuration 配置Spring 并加载Spring容器

Project Directory

 

Maven Dependency

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.12.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>org.fool</groupId>
    <artifactId>hellospring</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

View Code