IOC(一). IOC容器初始化过程 -> AnnotationConfigApplicationContext.this()方法

女爷i 2023-07-13 03:11 94阅读 0赞

一. 初始化两个扫描器,并且价值基础的注解过滤器的BeanPostProcessor的bean定义 --—> this()

1.  this.reader = new AnnotatedBeanDefinitionReader(this); 注解读取器，注入了基本的processor Bean定义

this.beanNameGenerator = new AnnotationBeanNameGenerator();  // 名字生成器
    this.scopeMetadataResolver = new AnnotationScopeMetadataResolver();  // 注解范围
    Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
    Assert.notNull(environment, "Environment must not be null");
    this.registry = registry;  // 当前context，也是个BeanDefinitionRegistry
    this.conditionEvaluator = new ConditionEvaluator(registry, environment, (ResourceLoader)null);
    AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);  // 注入核心注解的处理器

**核心为 AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);调到registerAnnotationConfigProcessors方法**

public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(BeanDefinitionRegistry registry, Object source) {
        DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);  //当前context也是DefaultListableBeanFactory
        if (beanFactory != null) {
            if (!(beanFactory.getDependencyComparator() instanceof AnnotationAwareOrderComparator)) {
                beanFactory.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
            }
    
            if (!(beanFactory.getAutowireCandidateResolver() instanceof ContextAnnotationAutowireCandidateResolver)) {
                beanFactory.setAutowireCandidateResolver(new ContextAnnotationAutowireCandidateResolver());
            }
        }
    
        Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet(8);  // 固定8个
        RootBeanDefinition def;
        if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalConfigurationAnnotationProcessor")) {//internalConfigurationAnnotationProcessor配置注解Processor,是个BeanDefinitionRegistryPostProcessor
            def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalConfigurationAnnotationProcessor"));
        }
    
        if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalAutowiredAnnotationProcessor")) {// Autowired注解处理器， 是个InstantiationAwareBeanPostProcessorAdapter
            def = new RootBeanDefinition(AutowiredAnnotationBeanPostProcessor.class);
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalAutowiredAnnotationProcessor"));
        }
    
        if (!registry.containsBeanDefinition("org.springframework.context.annotation.internalRequiredAnnotationProcessor")) {// required注解处理器
            def = new RootBeanDefinition(RequiredAnnotationBeanPostProcessor.class);
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalRequiredAnnotationProcessor"));
        }
    
        if (jsr250Present && !registry.containsBeanDefinition("org.springframework.context.annotation.internalCommonAnnotationProcessor")) {  // jsr250的，如postConstruct，是个InitDestroyAnnotationBeanPostProcessor
            def = new RootBeanDefinition(CommonAnnotationBeanPostProcessor.class);
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalCommonAnnotationProcessor"));
        }
    
        if (jpaPresent && !registry.containsBeanDefinition("org.springframework.context.annotation.internalPersistenceAnnotationProcessor")) {
            def = new RootBeanDefinition();  // internalPersistenceAnnotationProcessor,数据库JPA支持
    
            try {
                def.setBeanClass(ClassUtils.forName("org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor", AnnotationConfigUtils.class.getClassLoader()));
            } catch (ClassNotFoundException var6) {
                throw new IllegalStateException("Cannot load optional framework class: org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor", var6);
            }
    
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.annotation.internalPersistenceAnnotationProcessor"));
        }
    
        if (!registry.containsBeanDefinition("org.springframework.context.event.internalEventListenerProcessor")) { // 事件监听
            def = new RootBeanDefinition(EventListenerMethodProcessor.class);
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.event.internalEventListenerProcessor"));
        }
    
        if (!registry.containsBeanDefinition("org.springframework.context.event.internalEventListenerFactory")) {
            def = new RootBeanDefinition(DefaultEventListenerFactory.class); // DefaultEventListenerFactory
            def.setSource(source);
            beanDefs.add(registerPostProcessor(registry, def, "org.springframework.context.event.internalEventListenerFactory"));
        }
    
        return beanDefs;
    }

以上为AnnotatedBeanDefinitionReader初始化核心

1.  类路径扫描器：`this.scanner = new ClassPathBeanDefinitionScanner(this);`

this.beanDefinitionDefaults = new BeanDefinitionDefaults();
    this.beanNameGenerator = new AnnotationBeanNameGenerator();
    this.scopeMetadataResolver = new AnnotationScopeMetadataResolver();
    this.includeAnnotationConfig = true;
    Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
    this.registry = registry;
    if (useDefaultFilters) {
        this.registerDefaultFilters();  // 搞了filter
    }
    
    
    this.setEnvironment(environment);
    this.setResourceLoader(resourceLoader);

以上流程中都没有实例化bean，全部都是bean定义