spring源码分析(五)-finishRefresh方法

妖狐艹你老母 2022-12-28 14:12 130阅读 0赞

### 文章目录 ###

*   *   *  finishRefresh
         *   *  initLifecycleProcessor
             *  getLifecycleProcessor().onRefresh();
             *  publishEvent(new ContextRefreshedEvent(this));
             *  LiveBeansView.registerApplicationContext(this);
         *  完结撒花

### finishRefresh ###

前面大概讲了一下spring通过反射创建bean,对bean进行属性赋值,这时候spring容器大体都加载完成了,单例bean都初始化完成,属性也都赋值了,进行最后一步了,完成刷新方法了  
源码:

protected void finishRefresh() { 
    		// Initialize lifecycle processor for this context.
        // 为此上下文初始化生命周期处理器
    		initLifecycleProcessor();
    
    		// Propagate refresh to lifecycle processor first.
        // 将刷新完成事件广播到生命周期处理器
    		getLifecycleProcessor().onRefresh();
    
    		// Publish the final event.
        // 广播上下文刷新完成事件
    		publishEvent(new ContextRefreshedEvent(this));
    
    		// Participate in LiveBeansView MBean, if active.
        // 将spring容器注册到LiveBeansView
    		LiveBeansView.registerApplicationContext(this);
    	}

#### initLifecycleProcessor ####

protected void initLifecycleProcessor() { 
    		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        // 判断BeanFactory是否已经存在生命周期处理器（固定使用beanName=lifecycleProcessor）
        if (beanFactory.containsLocalBean(LIFECYCLE_PROCESSOR_BEAN_NAME)) { 
          //赋值
    			this.lifecycleProcessor =
    					beanFactory.getBean(LIFECYCLE_PROCESSOR_BEAN_NAME, LifecycleProcessor.class);
    			if (logger.isDebugEnabled()) { 
    				logger.debug("Using LifecycleProcessor [" + this.lifecycleProcessor + "]");
    			}
    		}
    		else { 
    		  //不存在,新建DefaultLifecycleProcessor
    			DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor();
    			defaultProcessor.setBeanFactory(beanFactory);
    			this.lifecycleProcessor = defaultProcessor;
    			beanFactory.registerSingleton(LIFECYCLE_PROCESSOR_BEAN_NAME, this.lifecycleProcessor);
    			if (logger.isDebugEnabled()) { 
    				logger.debug("Unable to locate LifecycleProcessor with name '" +
    						LIFECYCLE_PROCESSOR_BEAN_NAME +
    						"': using default [" + this.lifecycleProcessor + "]");
    			}
    		}
    	}

#### getLifecycleProcessor().onRefresh(); ####

// Internal helpers
    	// 根据阶段执行Lifecycle的start方法
    	private void startBeans(boolean autoStartupOnly) { 
    		Map<String, Lifecycle> lifecycleBeans = getLifecycleBeans();
    		Map<Integer, LifecycleGroup> phases = new HashMap<Integer, LifecycleGroup>();
    		for (Map.Entry<String, ? extends Lifecycle> entry : lifecycleBeans.entrySet()) { 
    			Lifecycle bean = entry.getValue();
    			if (!autoStartupOnly || (bean instanceof SmartLifecycle && ((SmartLifecycle) bean).isAutoStartup())) { 
    				int phase = getPhase(bean);
    				LifecycleGroup group = phases.get(phase);
    				if (group == null) { 
    					group = new LifecycleGroup(phase, this.timeoutPerShutdownPhase, lifecycleBeans, autoStartupOnly);
    					phases.put(phase, group);
    				}
    				group.add(entry.getKey(), bean);
    			}
    		}
    		if (!phases.isEmpty()) { 
    			List<Integer> keys = new ArrayList<Integer>(phases.keySet());
    			Collections.sort(keys);
    			for (Integer key : keys) { 
    				phases.get(key).start();
    			}
    		}
    	}

#### publishEvent(new ContextRefreshedEvent(this)); ####

protected void publishEvent(Object event, ResolvableType eventType) { 
    		Assert.notNull(event, "Event must not be null");
    		if (logger.isTraceEnabled()) { 
    			logger.trace("Publishing event in " + getDisplayName() + ": " + event);
    		}
    
    		// Decorate event as an ApplicationEvent if necessary
        // 将事件封装为ApplicationEvent
    		ApplicationEvent applicationEvent;
    		if (event instanceof ApplicationEvent) { 
    			applicationEvent = (ApplicationEvent) event;
    		}
    		else { 
    			applicationEvent = new PayloadApplicationEvent<Object>(this, event);
    			if (eventType == null) { 
    				eventType = ((PayloadApplicationEvent<?>) applicationEvent).getResolvableType();
    			}
    		}
    
    		// Multicast right now if possible - or lazily once the multicaster is initialized
    		if (this.earlyApplicationEvents != null) { 
    			this.earlyApplicationEvents.add(applicationEvent);
    		}
    		else { 
    		  //使用事件广播器,广播时间
    			getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType);
    		}
    
    		// Publish event via parent context as well...
        // 通过parent发布时间
    		if (this.parent != null) { 
    			if (this.parent instanceof AbstractApplicationContext) { 
    				((AbstractApplicationContext) this.parent).publishEvent(event, eventType);
    			}
    			else { 
    				this.parent.publishEvent(event);
    			}
    		}
    	}

#### LiveBeansView.registerApplicationContext(this); ####

// 向MBeanServer 托管Live Beans,也不知道要干啥…

### 完结撒花 ###

> 至此,spring源码的主流程基本都过了一遍,后面对一些单独的功能进行单独的讲.回顾spring的流程,就是创建bean的流程,然后就是各种后置处理器,bean工厂的后置处理器,和bean后置处理器,这些处理器做了很多的时候,这些处理器的执行时机也十分重要,基本就是在容器的创建过程中和bean创建前后~,spring对处理器进行了一些扩展,理解这些后置处理器十分重要