Spring - BeanFactoryPostProcessor 扩展接口
文章目录
- Pre
- org.springframework.beans.factory.config.BeanFactoryPostProcessor
- 源码探究
- 1 是否实现BeanDefinitionRegistryPostProcessor 接口,分别写入集合
- 2 处理实现了的PriorityOrdered和 BeanDefinitionRegistryPostProcessors 的 bean
- 3. 处理实现了的Ordered和BeanDefinitionRegistryPostProcessors 的 bean
- 4 处理其他实现了BeanDefinitionRegistryPostProcessor的bean
- 5 invokeBeanFactoryPostProcessors
- 6 除了试下BeanDefinitionRegistryPostProcessor之外的其他 实现了BeanFactoryPostProcessor接口的bean 分类
- 7 处理 PriorityOrdered ,invokeBeanDefinitionRegistryPostProcessors
- 8 处理 Ordered ,invokeBeanDefinitionRegistryPostProcessors
- 9 处理剩下的 ,invokeBeanDefinitionRegistryPostProcessors
- 10 invokeBeanDefinitionRegistryPostProcessors & invokeBeanFactoryPostProcessors 分析
- BeanFactoryPostProcessor的处理流程
- 扩展方式
Pre
Spring Boot - 扩展接口一览
org.springframework.beans.factory.config.BeanFactoryPostProcessor
这个接口是beanFactory的扩展接口,调用时机在spring在读取beanDefinition信息之后,实例化bean之前。
在这个时机,用户可以通过实现这个扩展接口来自行处理一些东西,比如修改已经注册的beanDefinition的元信息
package org.springframework.beans.factory.config;import org.springframework.beans.BeansException;/*** Factory hook that allows for custom modification of an application context's* bean definitions, adapting the bean property values of the context's underlying* bean factory.** <p>Useful for custom config files targeted at system administrators that* override bean properties configured in the application context. See* {@link PropertyResourceConfigurer} and its concrete implementations for* out-of-the-box solutions that address such configuration needs.** <p>A {@code BeanFactoryPostProcessor} may interact with and modify bean* definitions, but never bean instances. Doing so may cause premature bean* instantiation, violating the container and causing unintended side-effects.* If bean instance interaction is required, consider implementing* {@link BeanPostProcessor} instead.** <h3>Registration</h3>* <p>An {@code ApplicationContext} auto-detects {@code BeanFactoryPostProcessor}* beans in its bean definitions and applies them before any other beans get created.* A {@code BeanFactoryPostProcessor} may also be registered programmatically* with a {@code ConfigurableApplicationContext}.** <h3>Ordering</h3>* <p>{@code BeanFactoryPostProcessor} beans that are autodetected in an* {@code ApplicationContext} will be ordered according to* {@link org.springframework.core.PriorityOrdered} and* {@link org.springframework.core.Ordered} semantics. In contrast,* {@code BeanFactoryPostProcessor} beans that are registered programmatically* with a {@code ConfigurableApplicationContext} will be applied in the order of* registration; any ordering semantics expressed through implementing the* {@code PriorityOrdered} or {@code Ordered} interface will be ignored for* programmatically registered post-processors. Furthermore, the* {@link org.springframework.core.annotation.Order @Order} annotation is not* taken into account for {@code BeanFactoryPostProcessor} beans.** @author Juergen Hoeller* @author Sam Brannen* @since 06.07.2003* @see BeanPostProcessor* @see PropertyResourceConfigurer*/
@FunctionalInterface
public interface BeanFactoryPostProcessor {/*** Modify the application context's internal bean factory after its standard* initialization. All bean definitions will have been loaded, but no beans* will have been instantiated yet. This allows for overriding or adding* properties even to eager-initializing beans.* @param beanFactory the bean factory used by the application context* @throws org.springframework.beans.BeansException in case of errors*/void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;}
spring容器初始化时,从资源中读取到bean的相关定义后,保存在beanFactory的成员变量中(DefaultListableBeanFactory#beanDefinitionMap)
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);
实例化bean的操作就是依据这些BeanDefinition来做的。
在实例化之前,spring允许我们通过自定义扩展来改变bean的定义,定义一旦变了,后面的实例也就变了,而beanFactory后置处理器BeanFactoryPostProcessor就是用来改变bean定义的。
源码探究
AbstractApplicationContext#refresh 继续走起
继续
// Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);
主要功能是: 找出所有beanFactory后置处理器,并且调用这些处理器来改变bean的定义
继续 org.springframework.context.support.AbstractApplicationContext#invokeBeanFactoryPostProcessors
/*** Instantiate and invoke all registered BeanFactoryPostProcessor beans,* respecting explicit order if given.* <p>Must be called before singleton instantiation.*/protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());.......
我们重点关注PostProcessorRegistrationDelegate#invokeBeanFactoryPostProcessors
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
代码比较长,我们逐段看一下
1 是否实现BeanDefinitionRegistryPostProcessor 接口,分别写入集合
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {BeanDefinitionRegistryPostProcessor registryProcessor =(BeanDefinitionRegistryPostProcessor) postProcessor;registryProcessor.postProcessBeanDefinitionRegistry(registry);registryProcessors.add(registryProcessor);}else {regularPostProcessors.add(postProcessor);}}
遍历入参 beanFactoryPostProcessors , 是否实现了BeanDefinitionRegistryPostProcessor,分别放入两个集合:registryProcessors和regularPostProcessors;
2 处理实现了的PriorityOrdered和 BeanDefinitionRegistryPostProcessors 的 bean
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.String[] postProcessorNames =beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);for (String ppName : postProcessorNames) {if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));processedBeans.add(ppName);}}sortPostProcessors(currentRegistryProcessors, beanFactory);registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry, beanFactory.getApplicationStartup());currentRegistryProcessors.clear();
找出所有实现了BeanDefinitionRegistryPostProcessor接口和PriorityOrdered接口的bean,放入registryProcessors集合,根据PriorityOrdered接口来排序,然后这些bean会被invokeBeanDefinitionRegistryPostProcessors
方法执行;
3. 处理实现了的Ordered和BeanDefinitionRegistryPostProcessors 的 bean
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));processedBeans.add(ppName);}}sortPostProcessors(currentRegistryProcessors, beanFactory);registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry, beanFactory.getApplicationStartup());currentRegistryProcessors.clear();
找出所有实现了BeanDefinitionRegistryPostProcessor接口和Ordered接口的bean,放入registryProcessors集合,根据Ordered接口来排序,然后这些bean会被invokeBeanDefinitionRegistryPostProcessors
方法执行;
4 处理其他实现了BeanDefinitionRegistryPostProcessor的bean
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.boolean reiterate = true;while (reiterate) {reiterate = false;postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName)) {currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));processedBeans.add(ppName);reiterate = true;}}sortPostProcessors(currentRegistryProcessors, beanFactory);registryProcessors.addAll(currentRegistryProcessors);invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry, beanFactory.getApplicationStartup());currentRegistryProcessors.clear();}
对于那些实现了BeanDefinitionRegistryPostProcessor接口,但是没有实现PriorityOrdered和Ordered的bean也被找出来,然后这些bean会被invokeBeanDefinitionRegistryPostProcessors
方法执行
5 invokeBeanFactoryPostProcessors
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
6 除了试下BeanDefinitionRegistryPostProcessor之外的其他 实现了BeanFactoryPostProcessor接口的bean 分类
// Do not initialize FactoryBeans here: We need to leave all regular beans// uninitialized to let the bean factory post-processors apply to them!String[] postProcessorNames =beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,// Ordered, and the rest.List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();List<String> orderedPostProcessorNames = new ArrayList<>();List<String> nonOrderedPostProcessorNames = new ArrayList<>();for (String ppName : postProcessorNames) {if (processedBeans.contains(ppName)) {// skip - already processed in first phase above}else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));}else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {orderedPostProcessorNames.add(ppName);}else {nonOrderedPostProcessorNames.add(ppName);}}
找出实现了BeanFactoryPostProcessor接口的bean,注意这里已将前面实现了BeanDefinitionRegistryPostProcessor接口的bean给剔除了
if (processedBeans.contains(ppName)) {// skip - already processed in first phase above
}
将这些bean分为三类:
- 实现了PriorityOrdered接口的放入priorityOrderedPostProcessors,
- 实现了Ordered接口的放入orderedPostProcessorNames,
- 其他的放入nonOrderedPostProcessorNames,这段代码是关键,自定义的实现BeanFactoryPostProcessor接口的bean就会在此处被查找出来。
7 处理 PriorityOrdered ,invokeBeanDefinitionRegistryPostProcessors
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.sortPostProcessors(priorityOrderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
8 处理 Ordered ,invokeBeanDefinitionRegistryPostProcessors
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());for (String postProcessorName : orderedPostProcessorNames) {orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));}sortPostProcessors(orderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
9 处理剩下的 ,invokeBeanDefinitionRegistryPostProcessors
// Finally, invoke all other BeanFactoryPostProcessors.List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());for (String postProcessorName : nonOrderedPostProcessorNames) {nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));}invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
10 invokeBeanDefinitionRegistryPostProcessors & invokeBeanFactoryPostProcessors 分析
从上面的分析可以发现,所有实现了BeanFactoryPostProcessor
接口的bean,都被作为入参,然后调用了invokeBeanDefinitionRegistryPostProcessors
或者invokeBeanFactoryPostProcessors
方法去处理
/*** Invoke the given BeanDefinitionRegistryPostProcessor beans.*/private static void invokeBeanDefinitionRegistryPostProcessors(Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry, ApplicationStartup applicationStartup) {for (BeanDefinitionRegistryPostProcessor postProcessor : postProcessors) {StartupStep postProcessBeanDefRegistry = applicationStartup.start("spring.context.beandef-registry.post-process").tag("postProcessor", postProcessor::toString);postProcessor.postProcessBeanDefinitionRegistry(registry);postProcessBeanDefRegistry.end();}}
/*** Invoke the given BeanFactoryPostProcessor beans.*/private static void invokeBeanFactoryPostProcessors(Collection<? extends BeanFactoryPostProcessor> postProcessors, ConfigurableListableBeanFactory beanFactory) {for (BeanFactoryPostProcessor postProcessor : postProcessors) {StartupStep postProcessBeanFactory = beanFactory.getApplicationStartup().start("spring.context.bean-factory.post-process").tag("postProcessor", postProcessor::toString);postProcessor.postProcessBeanFactory(beanFactory);postProcessBeanFactory.end();}}
对每个BeanFactoryPostProcessor
接口的实现类,都调用了其接口方法。
不同的是 对于实现了BeanDefinitionRegistryPostProcessor
接口的bean,调用其postProcessBeanDefinitionRegistry
方法的时候,入参是BeanDefinitionRegistry
,而非BeanFactory,因此,实现了BeanDefinitionRegistryPostProcessor
接口的bean,其postProcessBeanDefinitionRegistry
在被调用时,可以通过入参BeanDefinitionRegistry
来做更多和bean的定义有关的操作,例如注册bean等等、
BeanFactoryPostProcessor的处理流程
小结一下:
ApplicationContext
扩展类可以调用AbstractApplicationContext.addBeanFactoryPostProcessor
方法,将自定义的BeanFactoryPostProcessor
实现类保存到ApplicationContext
中;- spring容器初始化时,上一步中被加入到
ApplicationContext
的bean会被优先调用其postProcessBeanFactory
方法; - 自定义的
BeanFactoryPostProcessor
接口实现类,也会被找出来,然后调用其postProcessBeanFactory
方法; postProcessBeanFactory
方法被调用时,beanFactory会被作为参数传入,自定义类中可以使用该参数来处理bean的定义,达到业务需求;- 此时的spring容器还没有开始实例化bean,因此自定义的
BeanFactoryPostProcessor
实现类不要做与bean实例有关的操作,而是做一些与bean定义有关的操作,例如修改某些字段的值,这样后面实例化的bean的就会有相应的改变;
扩展方式
package com.artisan.bootspringextend.testextends;import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.annotation.Configuration;/*** @author 小工匠* @version 1.0 * @date 2022/11/27 16:58* @mark: show me the code , change the world*/@Slf4j
@Configuration
public class ExtendBeanFactoryPostProcessor implements BeanFactoryPostProcessor {@Overridepublic void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {log.info("----->postProcessBeanFactory called ");}
}
Spring - BeanFactoryPostProcessor 扩展接口相关推荐
- Spring8:一些常用的Spring Bean扩展接口
前言 Spring是一款非常强大的框架,可以说是几乎所有的企业级Java项目使用了Spring,而Bean又是Spring框架的核心. Spring框架运用了非常多的设计模式,从整体上看,它的设计严格 ...
- java 扩展接口_详解常用的Spring Bean扩展接口
前言 Spring是一款非常强大的框架,可以说是几乎所有的企业级Java项目使用了Spring,而Bean又是Spring框架的核心. Spring框架运用了非常多的设计模式,从整体上看,它的设计严格 ...
- Spring - BeanDefinitionRegistryPostProcessor 扩展接口 动态注册bean
文章目录 Pre org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor 接口的继承关系 BeanD ...
- Spring - InstantiationAwareBeanPostProcessor 扩展接口
文章目录 Pre org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor InstantiationA ...
- Spring - DisposableBean扩展接口
文章目录 Pre org.springframework.beans.factory.DisposableBean 使用场景 源码解析 扩展示例 Pre Spring Boot - 扩展接口一览 or ...
- Spring - ApplicationContextInitializer 扩展接口
文章目录 Pre org.springframework.context.ApplicationContextInitializer扩展点 扩展接口 扩展生效方式 方式一 : Spring SPI扩展 ...
- Spring Boot - 扩展接口一览
文章目录 扩展接口 扩展接口
- SpringBoot2 | Spring IOC 流程中核心扩展接口的12个扩展点源码分析(十一)
微信公众号:吉姆餐厅ak 学习更多源码知识,欢迎关注. SpringBoot2 | SpringBoot启动流程源码分析(一) SpringBoot2 | SpringBoot启动流程源码分析(二) ...
- 动态管理配置文件扩展接口EnvironmentPostProcessor
SpringBoot支持动态的读取文件,留下的扩展接口org.springframework.boot.env.EnvironmentPostProcessor.这个接口是spring包下的,使用这个 ...
最新文章
- Spring Boot统一异常处理的拦截指南
- 相机定位 | cv paper整理
- linux之scp命令
- ASP.NET生成WORD文档服务器部署注意事项
- julia fit 函数_带有Julia中示例的flipsign()函数
- YOLOv4 | 用C++ 和OpenCV 实现视频目标检测
- ubuntu安装python_与你分享Ubuntu修改源和安装pycharm
- 摄像机成像公式、外参、内参(转载)
- C++ 虚函数表详解
- 25.专栏订阅者利用专栏技术再现无线密码破解
- 使用stress,压力测试K8S的POD cpu
- ActiveSync同步使用方法
- 验证码图片生成和验证
- python游戏数据分析
- BUCK电源芯片做升压电源的方法(1)
- Intellij Idea 好用插件之GsonFormat
- 多元统计分析基于r课后答案_何晓群版—多元统计分析课后练习答案.pdf
- 贝叶斯网络python代码_贝叶斯网络,看完这篇我终于理解了(附代码)!
- 套利套保模型|BVAR、ECM、GARCH、价差
- 新员工入职表_员工培训
热门文章
- 200228批量导入开票接口出错,用另外一种方式解决,快速开票顺畅
- 多层级部门结构展示与分级汇总
- 读书随记-方向和结果
- “网络状态变成一条虚线”的解决办法(右下角网络图标突然消失情况)
- css引入woff ttf,css引用跨域字体文件woff,eot,ttf问题
- Java解析woff_ttf字体转换成web中使用的woff、svg、eot格式字体
- 昆明网站建设公司排名榜
- 不能使用 UPN 格式的用户名登录到使用 IIS 6.0的FTP
- 你真的了解10G以太网吗?
- 什么情况下我们需要进行硬盘对拷?硬盘对拷怎么操作?