死磕源码系列【@SpringBootConfiguration注解详解】

逃离我推掉我的手 2022-12-08 12:55 105阅读 0赞

> @SpringBootConfiguration注解是@SpringBootApplication组合注解中的一员，今天就来重点了解下这个注解的作用。

##### 1.首先看下注解源码 #####

/* * Copyright 2012-2019 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */
 
 package org.springframework.boot;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.annotation.AliasFor;
 
 /** * Indicates that a class provides Spring Boot application * {@link Configuration @Configuration}. Can be used as an alternative to the Spring's * standard {@code @Configuration} annotation so that configuration can be found * automatically (for example in tests). * * Application should only ever include one {@code @SpringBootConfiguration} and * most idiomatic Spring Boot applications will inherit it from * {@code @SpringBootApplication}. * * @author Phillip Webb * @author Andy Wilkinson * @since 1.4.0 */
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
 @Configuration
 public @interface SpringBootConfiguration { 
 
 	/** * Specify whether {@link Bean @Bean} methods should get proxied in order to enforce * bean lifecycle behavior, e.g. to return shared singleton bean instances even in * case of direct {@code @Bean} method calls in user code. This feature requires * method interception, implemented through a runtime-generated CGLIB subclass which * comes with limitations such as the configuration class and its methods not being * allowed to declare {@code final}. * * The default is {@code true}, allowing for 'inter-bean references' within the * configuration class as well as for external calls to this configuration's * {@code @Bean} methods, e.g. from another configuration class. If this is not needed * since each of this particular configuration's {@code @Bean} methods is * self-contained and designed as a plain factory method for container use, switch * this flag to {@code false} in order to avoid CGLIB subclass processing. * * Turning off bean method interception effectively processes {@code @Bean} methods * individually like when declared on non-{@code @Configuration} classes, a.k.a. * "@Bean Lite Mode" (see {@link Bean @Bean's javadoc}). It is therefore behaviorally * equivalent to removing the {@code @Configuration} stereotype. * @return whether to proxy {@code @Bean} methods * @since 2.2 */
 	@AliasFor(annotation = Configuration.class)
 	boolean proxyBeanMethods() default true;
 
 }

可以看到该注解是@Configuration的派生注解，作用和@Configuration一样标注当前类是一个配置类，只不过@SpringBootConfiguration注解是springboot的注解，@Configuration是Spring注解；应用程序应该仅包含一个@SpringBootConfiguration注解，大多数通用的springboot 应用程序会自动继承@SpringBootConfiguration。

参考@Configuration用法：[https://blog.csdn.net/yaomingyang/article/details/108238121][https_blog.csdn.net_yaomingyang_article_details_108238121]

GitHub地址：[https://github.com/mingyang66/spring-parent][https_github.com_mingyang66_spring-parent]

[https_blog.csdn.net_yaomingyang_article_details_108238121]: https://blog.csdn.net/yaomingyang/article/details/108238121
[https_github.com_mingyang66_spring-parent]: https://github.com/mingyang66/spring-parent