springboot源码分析(六)-refresh方法分析

概述

　　在学习springboot时候，会牵涉到很多的知识，而refresh方法可以说其中的核心方法，为什么这么说，因为整个spring的核心aop和ioc都和这个方法有关，既然这个方法那么重要，那我们就分析一下这个方法到底干了什么。

refresh()调用的核心方法预览

看了上面这个图是不是都晕了，其实不用晕，这里面很多的方法只是在做一些准备的工作和监听的工作，真正核心的就两三个方法，那我就把核心的方法先列出来，

• invokeBeanFactoryPostProcessors(beanFactory),核心方法，将程序中的所有bean放入到beanDefinitionMap中，注意这一步并没有实例化bean，而是获得bean的beanDefinition
• finishBeanFactoryInitialization(beanFactory),核心方法，将上面放入到beanDefinitionMap中的非懒加载的bean都实例化，这两个方法可以说是让ioc起作用的核心方法

其实核心的方法我觉得就这两个，剩下的都是一些准备性的工作，ok，下面我们就逐个分析一下每个方法，不重要的方法我就简单说一下，我觉得没必要每个方法都全部吃透，搞明白核心方法就可以了，spring代码那么多，又不是自己要去写一个spring，没必要全部吃透。

prepareRefresh()

　　这个方法，从名字就可以看出来，就是一个为了执行refresh()方法做准备的方法，下面我们看一下代码

protected void prepareRefresh() {
　　　　　//设置开始时间
        this.startupDate = System.currentTimeMillis();
        this.closed.set(false);
        this.active.set(true);
        if (this.logger.isDebugEnabled()) {
            if (this.logger.isTraceEnabled()) {
                this.logger.trace("Refreshing " + this);
            } else {
                this.logger.debug("Refreshing " + this.getDisplayName());
            }
        }
　　　　　
        this.initPropertySources();
　　　　　//校验一些关键的环境信息是否存在 
        this.getEnvironment().validateRequiredProperties();
        if (this.earlyApplicationListeners == null) {
            this.earlyApplicationListeners = new LinkedHashSet(this.applicationListeners);
        } else {
            this.applicationListeners.clear();
            this.applicationListeners.addAll(this.earlyApplicationListeners);
        }

        this.earlyApplicationEvents = new LinkedHashSet();
    }

总结：这个方法总的来说就是设置了一下启动的时间，校验了一下环境参数。

obtainFreshBeanFactory()

　　这个方法从名称也可以看出来获取beanFactory的，至于beanFactory是什么，相信大家也应该清楚，整个spring的核心接口，用于生产bean，为他的实现类DefaultListableBeanFactory,ApplicationContext等提供了最基本的规范，下面看一下代码

protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
        this.refreshBeanFactory();
        return this.getBeanFactory();
    }

第一个方法refreshBeanFactory，这个方法就是未beanFactory设置了一个序列化id，我们主要看一下第二个，这里使用了模板模式，真是实现这个getBeanFactory()的是GenericApplicationContext(),我们看一下这个类的构造方法

    public GenericApplicationContext() {
        this.customClassLoader = false;
        this.refreshed = new AtomicBoolean();
　　　　　//这里new了一个beanFactory
        this.beanFactory = new DefaultListableBeanFactory();
    }

我们看一下this.getBeanFactory();方法代码

 public final ConfigurableListableBeanFactory getBeanFactory() {
        return this.beanFactory;
    }

总结：obtainFreshBeanFactory（）方法就是为了返回new DefaultListableBeanFactory();

this.prepareBeanFactory(beanFactory);

　　同样，从名字就可以看出来是为beanFactory做一些准备工作，因为上一步已经获取到beanFactory

 protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        beanFactory.setBeanClassLoader(this.getClassLoader());
        beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
        beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, this.getEnvironment()));
　　　　　//这里设置了一个beanPostProcessor，这个接口的作用后面再说，这个接口和AOP有关
        beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
        beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
        beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
        beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
        beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
        beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
        beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
        beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
        beanFactory.registerResolvableDependency(ResourceLoader.class, this);
        beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
        beanFactory.registerResolvableDependency(ApplicationContext.class, this);
        beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
        if (beanFactory.containsBean("loadTimeWeaver")) {
            beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
            beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
        }

        if (!beanFactory.containsLocalBean("environment")) {
            beanFactory.registerSingleton("environment", this.getEnvironment());
        }

        if (!beanFactory.containsLocalBean("systemProperties")) {
            beanFactory.registerSingleton("systemProperties", this.getEnvironment().getSystemProperties());
        }

        if (!beanFactory.containsLocalBean("systemEnvironment")) {
            beanFactory.registerSingleton("systemEnvironment", this.getEnvironment().getSystemEnvironment());
        }

    }

总结：这个里面代码一大坨，基本就是向beanFactory中设置了一个属性，为了后面使用。

postProcessBeanFactory(beanFactory);

　　这个方法在这里并没有实现，而是交给了子类实现，这里就不分析了

invokeBeanFactoryPostProcessors(beanFactory);

　　这个就是核心方法了，看一下代码

 protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
        PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, this.getBeanFactoryPostProcessors());
        if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean("loadTimeWeaver")) {
            beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
            beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
        }

    }

进入PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, this.getBeanFactoryPostProcessors());

　　这个代码很长，但是大家不要怕，里面很多个循环只是在做重复的事情

public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
        Set<String> processedBeans = new HashSet();
        ArrayList regularPostProcessors;
        ArrayList registryProcessors;
        int var9;
        ArrayList currentRegistryProcessors;
        String[] postProcessorNames;
　　　　　//先判断beanFactory是不是实现了BeanDefinitionRegistry
        if (beanFactory instanceof BeanDefinitionRegistry) {
            BeanDefinitionRegistry registry = (BeanDefinitionRegistry)beanFactory;
            regularPostProcessors = new ArrayList();
            registryProcessors = new ArrayList();
            Iterator var6 = beanFactoryPostProcessors.iterator();

            while(var6.hasNext()) {
                BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor)var6.next();
　　　　　　　　　　//判断postProcessor是不是BeanDefinitionRegistryPostProcessor,这个接口继承了BeanFactoryPostProcessor
                if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
                    BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor)postProcessor;
　　　　　　　　　　　　//执行方法
                    registryProcessor.postProcessBeanDefinitionRegistry(registry);
                    registryProcessors.add(registryProcessor);
                } else {
                    regularPostProcessors.add(postProcessor);
                }
            }

            currentRegistryProcessors = new ArrayList();
　　　　　　　//获取beanFactory中实现了BeanDefinitionRegistryPostProcessor接口的bean
            postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
            String[] var16 = postProcessorNames;
            var9 = postProcessorNames.length;

            int var10;
            String ppName;
            for(var10 = 0; var10 < var9; ++var10) {
                ppName = var16[var10];
                if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
                    currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
                    processedBeans.add(ppName);
                }
            }
　　　　　　　//对postProcessor排序
            sortPostProcessors(currentRegistryProcessors, beanFactory);
            registryProcessors.addAll(currentRegistryProcessors);
　　　　　　　//<1.1>，执行postProcessor的postProcessBeanDefinitionRegistry()方法
            invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
　　　　　　　//执行完了之后，清空当前的后置处理器列表
            currentRegistryProcessors.clear();
　　　　　　　//<1.2>这一步和上一步的过程一样，但是这里获取到的这个处理器非常重要，是ConfigurationClassPostProcessor,这个类会处理所有的bean，并把其beanDefinition放入beanDefinitionMap中
            postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
            var16 = postProcessorNames;
            var9 = postProcessorNames.length;

            for(var10 = 0; var10 < var9; ++var10) {
                ppName = var16[var10];
                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);
            currentRegistryProcessors.clear();
            boolean reiterate = true;

            while(reiterate) {
                reiterate = false;

　　　　　　　　　　//这里的过程依然是一样的，把所有的postProcessor都执行一遍
                postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
                String[] var19 = postProcessorNames;
                var10 = postProcessorNames.length;

                for(int var26 = 0; var26 < var10; ++var26) {
                    String ppName = var19[var26];
                    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);
                currentRegistryProcessors.clear();
            }

            invokeBeanFactoryPostProcessors((Collection)registryProcessors, (ConfigurableListableBeanFactory)beanFactory);
            invokeBeanFactoryPostProcessors((Collection)regularPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
        } else {
            invokeBeanFactoryPostProcessors((Collection)beanFactoryPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
        }

        String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
        regularPostProcessors = new ArrayList();
        registryProcessors = new ArrayList();
        currentRegistryProcessors = new ArrayList();
        postProcessorNames = postProcessorNames;
        int var20 = postProcessorNames.length;

        String ppName;
        for(var9 = 0; var9 < var20; ++var9) {
            ppName = postProcessorNames[var9];
            if (!processedBeans.contains(ppName)) {
                if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
                    regularPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
                } else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
                    registryProcessors.add(ppName);
                } else {
                    currentRegistryProcessors.add(ppName);
                }
            }
        }

        sortPostProcessors(regularPostProcessors, beanFactory);
        invokeBeanFactoryPostProcessors((Collection)regularPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
        List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList(registryProcessors.size());
        Iterator var21 = registryProcessors.iterator();

        while(var21.hasNext()) {
            String postProcessorName = (String)var21.next();
            orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
        }

        sortPostProcessors(orderedPostProcessors, beanFactory);
        invokeBeanFactoryPostProcessors((Collection)orderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
        List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList(currentRegistryProcessors.size());
        Iterator var24 = currentRegistryProcessors.iterator();

        while(var24.hasNext()) {
            ppName = (String)var24.next();
            nonOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
        }

        invokeBeanFactoryPostProcessors((Collection)nonOrderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
        beanFactory.clearMetadataCache();
    }

 这个方法中写了很多的循环，每个循环干了什么事情呢？

• 找出beanFactory中所有的实现了BeanDefinitionRegistryPostProcessor接口和BeanFactoryPostProcessor接口的bean
• 对找出来的postProcessor进行排序
• 执行postProcessor中的postProcessBeanDefinitionRegistry()方法和postProcessBeanFactory()方法

那估计大家都有疑问了，为什么要写那么多循环，一个循环不就ok了，我自己觉得写一个中间那个while(reiterate)就可以了，没搞明白spring为什么要在这个while之前还要搞两个循环

<1.1>处代码

    private static void invokeBeanDefinitionRegistryPostProcessors(Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry) {
        Iterator var2 = postProcessors.iterator();

        while(var2.hasNext()) {
            BeanDefinitionRegistryPostProcessor postProcessor = (BeanDefinitionRegistryPostProcessor)var2.next();
　　　　　　　//就是调用每个postProcessor中的方法
            postProcessor.postProcessBeanDefinitionRegistry(registry);
        }

    }

<1.2>处代码，ConfigurationClassPostProcessor,我们看一下这个类的回调函数

 public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
        int registryId = System.identityHashCode(registry);
        if (this.registriesPostProcessed.contains(registryId)) {
            throw new IllegalStateException("postProcessBeanDefinitionRegistry already called on this post-processor against " + registry);
        } else if (this.factoriesPostProcessed.contains(registryId)) {
            throw new IllegalStateException("postProcessBeanFactory already called on this post-processor against " + registry);
        } else {
　　　　　　
            this.registriesPostProcessed.add(registryId);
　　　　　　　//执行这里的代码
            this.processConfigBeanDefinitions(registry);
        }
    }

进入this.processConfigBeanDefinitions(registry);

public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
        List<BeanDefinitionHolder> configCandidates = new ArrayList();
        String[] candidateNames = registry.getBeanDefinitionNames();
        String[] var4 = candidateNames;
        int var5 = candidateNames.length;

        for(int var6 = 0; var6 < var5; ++var6) {
            String beanName = var4[var6];
            BeanDefinition beanDef = registry.getBeanDefinition(beanName);
            if (beanDef.getAttribute(ConfigurationClassUtils.CONFIGURATION_CLASS_ATTRIBUTE) != null) {
                if (this.logger.isDebugEnabled()) {
                    this.logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
                }
            } else if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
                configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
            }
        }

        if (!configCandidates.isEmpty()) {
            configCandidates.sort((bd1, bd2) -> {
                int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
                int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
                return Integer.compare(i1, i2);
            });
            SingletonBeanRegistry sbr = null;
            if (registry instanceof SingletonBeanRegistry) {
                sbr = (SingletonBeanRegistry)registry;
                if (!this.localBeanNameGeneratorSet) {
                    BeanNameGenerator generator = (BeanNameGenerator)sbr.getSingleton("org.springframework.context.annotation.internalConfigurationBeanNameGenerator");
                    if (generator != null) {
                        this.componentScanBeanNameGenerator = generator;
                        this.importBeanNameGenerator = generator;
                    }
                }
            }

            if (this.environment == null) {
                this.environment = new StandardEnvironment();
            }

            ConfigurationClassParser parser = new ConfigurationClassParser(this.metadataReaderFactory, this.problemReporter, this.environment, this.resourceLoader, this.componentScanBeanNameGenerator, registry);
            Set<BeanDefinitionHolder> candidates = new LinkedHashSet(configCandidates);
            HashSet alreadyParsed = new HashSet(configCandidates.size());

            do {
　　　　　　　　　　//这里就是解析每个bean
                parser.parse(candidates);
                parser.validate();
                Set<ConfigurationClass> configClasses = new LinkedHashSet(parser.getConfigurationClasses());
                configClasses.removeAll(alreadyParsed);
                if (this.reader == null) {
                    this.reader = new ConfigurationClassBeanDefinitionReader(registry, this.sourceExtractor, this.resourceLoader, this.environment, this.importBeanNameGenerator, parser.getImportRegistry());
                }

                this.reader.loadBeanDefinitions(configClasses);
                alreadyParsed.addAll(configClasses);
                candidates.clear();
                if (registry.getBeanDefinitionCount() > candidateNames.length) {
                    String[] newCandidateNames = registry.getBeanDefinitionNames();
                    Set<String> oldCandidateNames = new HashSet(Arrays.asList(candidateNames));
                    Set<String> alreadyParsedClasses = new HashSet();
                    Iterator var12 = alreadyParsed.iterator();

                    while(var12.hasNext()) {
                        ConfigurationClass configurationClass = (ConfigurationClass)var12.next();
                        alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
                    }

                    String[] var23 = newCandidateNames;
                    int var24 = newCandidateNames.length;

                    for(int var14 = 0; var14 < var24; ++var14) {
                        String candidateName = var23[var14];
                        if (!oldCandidateNames.contains(candidateName)) {
                            BeanDefinition bd = registry.getBeanDefinition(candidateName);
                            if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) && !alreadyParsedClasses.contains(bd.getBeanClassName())) {
                                candidates.add(new BeanDefinitionHolder(bd, candidateName));
                            }
                        }
                    }

                    candidateNames = newCandidateNames;
                }
            } while(!candidates.isEmpty());

            if (sbr != null && !sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
                sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
            }

            if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
                ((CachingMetadataReaderFactory)this.metadataReaderFactory).clearCache();
            }

        }
    }

有兴趣的可以进入parse看一下，这个就是我们每次写程序写了很多的@Service,@Component,@Controller，都是这里解析的

总结：这个方法我只分析了invokeBeanFactoryPostProcessors，没有详细分析剩下的一大堆，如果有兴趣可以看看：【Spring】简述@Configuration配置类注册BeanDefinition到Spring容器的过程

finishBeanFactoryInitialization(beanFactory)

　　由于中间几个方法都不重要，就不分析了，直接分析这个方法

protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
        if (beanFactory.containsBean("conversionService") && beanFactory.isTypeMatch("conversionService", ConversionService.class)) {
            beanFactory.setConversionService((ConversionService)beanFactory.getBean("conversionService", ConversionService.class));
        }

        if (!beanFactory.hasEmbeddedValueResolver()) {
            beanFactory.addEmbeddedValueResolver((strVal) -> {
                return this.getEnvironment().resolvePlaceholders(strVal);
            });
        }

        String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
        String[] var3 = weaverAwareNames;
        int var4 = weaverAwareNames.length;

        for(int var5 = 0; var5 < var4; ++var5) {
            String weaverAwareName = var3[var5];
            this.getBean(weaverAwareName);
        }

        beanFactory.setTempClassLoader((ClassLoader)null);
        beanFactory.freezeConfiguration();
　　　　　//这一步就是将所有的非懒加载的bean初始化的步骤
        beanFactory.preInstantiateSingletons();
    }

进入beanFactory.preInstantiateSingletons();

public void preInstantiateSingletons() throws BeansException {
        if (this.logger.isTraceEnabled()) {
            this.logger.trace("Pre-instantiating singletons in " + this);
        }

        List<String> beanNames = new ArrayList(this.beanDefinitionNames);
        Iterator var2 = beanNames.iterator();

        while(true) {
            String beanName;
            Object bean;
            do {
                while(true) {
                    RootBeanDefinition bd;
                    do {
                        do {
                            do {
                                if (!var2.hasNext()) {
                                    var2 = beanNames.iterator();

                                    while(var2.hasNext()) {
                                        beanName = (String)var2.next();
                                        Object singletonInstance = this.getSingleton(beanName);
                                        if (singletonInstance instanceof SmartInitializingSingleton) {
                                            SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton)singletonInstance;
                                            if (System.getSecurityManager() != null) {
                                                AccessController.doPrivileged(() -> {
                                                    smartSingleton.afterSingletonsInstantiated();
                                                    return null;
                                                }, this.getAccessControlContext());
                                            } else {
                                                smartSingleton.afterSingletonsInstantiated();
                                            }
                                        }
                                    }

                                    return;
                                }

                                beanName = (String)var2.next();
                                bd = this.getMergedLocalBeanDefinition(beanName);
                            } while(bd.isAbstract());
                        } while(!bd.isSingleton());
                    } while(bd.isLazyInit());

                    if (this.isFactoryBean(beanName)) {
                        bean = this.getBean("&" + beanName);
                        break;
                    }

                    this.getBean(beanName);
                }
            } while(!(bean instanceof FactoryBean));

            FactoryBean<?> factory = (FactoryBean)bean;
            boolean isEagerInit;
            if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
                SmartFactoryBean var10000 = (SmartFactoryBean)factory;
                ((SmartFactoryBean)factory).getClass();
                isEagerInit = (Boolean)AccessController.doPrivileged(var10000::isEagerInit, this.getAccessControlContext());
            } else {
                isEagerInit = factory instanceof SmartFactoryBean && ((SmartFactoryBean)factory).isEagerInit();
            }

            if (isEagerInit) {
                this.getBean(beanName);
            }
        }
    }

这个方法，真是出奇的长，写的非常神奇，我还从没有写过这么多的循环嵌套，这个方法总的来说其实就是调用beanFactory.getBean()方法进行实例化bean,细节我是真没看头大

总结：这个方法非常重要，尤其是getBean方法，这个方法下一篇文章会分析

---

最后

　　一开始的打算是把每个方法仔细分析一遍，在分析的过程中发现确实没有多大必要，里面的逻辑写的太多，把核心的看一下就可以了，其实这个refresh()方法我写的比较简单，其实里面的逻辑还是挺多的。下一篇文章介绍getBean()方法

参考文章

SpringBoot源码分析之Spring容器的refresh过程

Spring源码-refresh方法

BeanFactory和FactoryBean的区别