spring源码解析之ioc-prepareBeanFactory

Bertha 。 2022-12-27 07:13 152阅读 0赞

上一篇，我们分析了beanDefinition的定义，接着，我们继续跟着源码，来看看spring ioc在启动阶段都做了什么事

还是来贴出核心代码

public void refresh() throws BeansException, IllegalStateException { 
            synchronized(this.startupShutdownMonitor) { 
                this.prepareRefresh();
                ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
                this.prepareBeanFactory(beanFactory);
    
                try { 
                    this.postProcessBeanFactory(beanFactory);
                    this.invokeBeanFactoryPostProcessors(beanFactory);
                    this.registerBeanPostProcessors(beanFactory);
                    this.initMessageSource();
                    this.initApplicationEventMulticaster();
                    this.onRefresh();
                    this.registerListeners();
                    this.finishBeanFactoryInitialization(beanFactory);
                    this.finishRefresh();
                } catch (BeansException var9) { 
                    if (this.logger.isWarnEnabled()) { 
                        this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var9);
                    }
    
                    this.destroyBeans();
                    this.cancelRefresh(var9);
                    throw var9;
                } finally { 
                    this.resetCommonCaches();
                }
    
            }
        }

在拿到了beanFactory之后，接着源码到了这一块 这也是本篇核心分析的内容

**在beanFactory正式工作之前的准备**

//往下看
    this.prepareBeanFactory(beanFactory);

准备工作

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { 
    		//设置classLoader
            beanFactory.setBeanClassLoader(this.getClassLoader());
            //设置bean表达式的解析器
            beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
            //设置属性文件的注册器（可能理解不对~~~）
            beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, this.getEnvironment()));
            //注册了第一个beanPostProcessor:ApplicationContextAwareProcessor 是new出来的
            beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
            //设置忽略的一些接口
            beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
            beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
            beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
            beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
            beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
            beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
            //正常工作需要依赖的一些bean
            beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
            beanFactory.registerResolvableDependency(ResourceLoader.class, this);
            beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
            beanFactory.registerResolvableDependency(ApplicationContext.class, this);
            //注册第二个beanPostProcessor：ApplicationListenerDetector 也是new出来的
            beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
            //loadTimeWarer的注册 我们没这个bean 忽略 感兴趣可以分析这个bean的作用
            if (beanFactory.containsBean("loadTimeWeaver")) { 
                beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
                beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
            }
    
    		//设置环境相关的bean 我们这里是默认的StandardEnvironment
            if (!beanFactory.containsLocalBean("environment")) { 
                beanFactory.registerSingleton("environment", this.getEnvironment());
            }
    		//设置系统参数相关的bean 默认的Properties
            if (!beanFactory.containsLocalBean("systemProperties")) { 
                beanFactory.registerSingleton("systemProperties", this.getEnvironment().getSystemProperties());
            }
    		//设置系统唤醒相关bean 还是默认的Collections$UnmodifiabneMap
            if (!beanFactory.containsLocalBean("systemEnvironment")) { 
                beanFactory.registerSingleton("systemEnvironment", this.getEnvironment().getSystemEnvironment());
            }
        }

至此，准备工作做完，我们需要知道的，这里**注册了两个beanPostProcessor**

beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
    beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));