springboot bean解析 及 refresh方法中的13个方法调用

IOC思想介绍

IOC优点

• 松耦合
• 灵活性
• 可维护

IOC缺点

• 配置繁琐
• 开发效率稍低
• 文件解析耗时

xml方式配置bean介绍

无参构造

Student类

import java.util.List;

public class Student {

    private String name;

    private Integer age;

    public Student() {
    }

    public Student(String name, Integer age) {
        this.name = name;
        this.age = age;
    }

    private List classList;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public List getClassList() {
        return classList;
    }

    public void setClassList(List classList) {
        this.classList = classList;
    }

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", classList=" + classList +
                '}';
    }
}

HelloService类

public class HelloService {

    private Student student;

    public void contextLoads() {
        System.out.println(student.toString());
    }

    public Student getStudent() {
        return student;
    }

    public void setStudent(Student student) {
        this.student = student;
    }
}

xml配置

    
        
        
        
            
                Math
                english
            
        
    

    
        
    

测试类

import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringRunner;

@SpringBootTest
@RunWith(SpringRunner.class)
@ContextConfiguration(locations = "classpath:ioc/demo.xml")
public class MystuflinkApplicationTests {

    @Autowired
    private HelloService helloService;

    @Test
    public void contextLoads() {

        helloService.contextLoads();

    }

}

console

Student{name='张三', age=13, classList=[Math, english]}

有参构造

其他与无参构造相同，只修改xml配置

xml配置

    
        
        
        
            
                Math
                english
            
        
    

    
        
    

console

Student{name='李四', age=21, classList=[Math, english]}

静态工厂方法

Animal类

public interface Animal {

    String getName();

}

Cat类

public class Cat implements Animal {
    @Override
    public String getName() {
        return "Cat";
    }
}

Dog类

public class Dog implements Animal {
    @Override
    public String getName() {
        return "Dag";
    }
}

AnimalFacory类

public class AnimalFacory {

    public static Animal getAnimal(String type) {
        switch (type) {
            case "dog":
                return new Dog();
            case "cat":
                return new Cat();
            default:
                return null;
        }
    }

}

xml配置

实例工厂方法

实例工厂相对于静态工厂来说，只需要修改下 xml即可

注解方式配置bean介绍

优点

使用简单
开发效率高
高内聚

缺点

配置分散
对象关系不清晰
配置修改需要重新编译工程

@Component声明

//Component注解会将HelloService实例自动添加到IOC容器中
@Component
public class HelloService {
}

配置类中使用@Bean

@Configuration
public class BeanConfiguration {

    @Bean("dog")
    public Animal getAnimal(){
        return new Dog();
    }

}

实现FactoryBean接口

import com.wwy.myspringboot.ioc.factory.Animal;
import com.wwy.myspringboot.ioc.factory.Cat;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.stereotype.Component;

@Component
public class MyCat implements FactoryBean {
@Override
public Animal getObject() throws Exception {
return new Cat();
}

@Override
public Class getObjectType() {
    return Animal.class;
}

}

实现BeanDefinitionRegistryPostProcessor

Monkey类

public class Monkey implements Animal{
    @Override
    public String getName() {
        return "Monkey";
    }
}

MyBeanRegister类，实现了BeanDefinitionRegistryPostProcessor接口

import com.wwy.mystuflink.myspringboot.ioc.factory.Monkey;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyBeanRegister implements BeanDefinitionRegistryPostProcessor {


    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        /*RootBeanDefinition beanDefinition = new RootBeanDefinition();
        beanDefinition.setBeanClass(Monkey.class);
        registry.registerBeanDefinition("monkey", beanDefinition);*/
        AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(Monkey.class).getRawBeanDefinition();
        registry.registerBeanDefinition("monkey", beanDefinition);
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

    }
}

实现ImportBeanDefinitionRegistrar

Bird类

public class Bird implements Animal {
    @Override
    public String getName() {
        return "Bird";
    }
}

MyBeanImport类，实现ImportBeanDefinitionRegistrar接口

import com.wwy.mystuflink.myspringboot.ioc.factory.Bird;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;

@Configuration
public class MyBeanImport implements ImportBeanDefinitionRegistrar {

    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) {
        RootBeanDefinition beanDefinition = new RootBeanDefinition();
        beanDefinition.setBeanClass(Bird.class);
        registry.registerBeanDefinition("bird", beanDefinition);
    }
}

测试类

重点注意需要加入注解：@Import(MyBeanImport.class)

import com.wwy.mystuflink.myspringboot.ioc.ann.MyBeanImport;
import com.wwy.mystuflink.myspringboot.ioc.factory.Animal;
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.annotation.Import;
import org.springframework.test.context.junit4.SpringRunner;

@SpringBootTest
@RunWith(SpringRunner.class)
@Import(MyBeanImport.class)
public class ApplicationTests {

    @Autowired
    @Qualifier("bird")
    private Animal bird;

    @Test
    public void test2() {
        System.out.println(bird.getName());
    }
}

refresh方法解析

方法简介

• bean配置读取加载入口
• spring框架启动流程
• 面试重点

设计13个子方法调用

方法入口地址

org.springframework.context.support.AbstractApplicationContext#refresh

refresh方法中的13个方法调用

    @Override
    public void refresh() throws BeansException, IllegalStateException {
        synchronized (this.startupShutdownMonitor) {
            StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");

            //准备此上下文以进行刷新
            prepareRefresh();

            // 告诉子类刷新内部bean工厂。
            ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

            // 准备bean工厂，以便在此上下文中使用
            prepareBeanFactory(beanFactory);

            try {
                // 该方法主要处理web请求相关的处理器，bean、以及相关配置
                postProcessBeanFactory(beanFactory);

                StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");
                // 调用在上下文中注册为bean的工厂处理器
                invokeBeanFactoryPostProcessors(beanFactory);

                // 注册拦截bean创建的bean处理器
                registerBeanPostProcessors(beanFactory);
                beanPostProcess.end();

                // 为此上下文初始化消息源
                initMessageSource();

                // 为此上下文初始化事件多播
                initApplicationEventMulticaster();

                // 初始化特定上下文子类中的其他特殊bean
                onRefresh();

                // 检查监听器bean并注册它们
                registerListeners();

                // 实例化所有剩余的（非惰性初始化）单例
                finishBeanFactoryInitialization(beanFactory);

                // 最后一步：发布相应的事件
                finishRefresh();
            }
            catch (BeansException ex) {
                if (logger.isWarnEnabled()) {
                    logger.warn("Exception encountered during context initialization - " +
                            "cancelling refresh attempt: " + ex);
                }
                // 销毁已创建的单例以避免悬空资源.
                destroyBeans();
                // 重置“活动”标志
                cancelRefresh(ex);
                // 将异常传播到调用方
                throw ex;
            }
            finally {
                // 重置Spring核心中的常见内省缓存，因为我们可能不再需要单例bean的元数据了
                resetCommonCaches();
                contextRefresh.end();
            }
        }
    }

1、prepareRefresh

• 容器状态设置
• 初始化属性设置
• 检查必备属性是否存在

/**
	 * 准备此上下文以进行刷新，设置其启动日期和
	 * 活动标志，以及执行属性源的任何初始化
	 */
	protected void prepareRefresh() {
		// 切换到运行状态
		this.startupDate = System.currentTimeMillis();
		this.closed.set(false);
		this.active.set(true);
		//是否Bebug启动
		if (logger.isDebugEnabled()) {
			if (logger.isTraceEnabled()) {
				logger.trace("Refreshing " + this);
			}
			else {
				logger.debug("Refreshing " + getDisplayName());
			}
		}

		//1、初始化上下文环境中的任何占位符属性源
		initPropertySources();

		// 2、验证标记为“需要”的所有属性是否可解析：
		// 查看 ConfigurablePropertyResolver#setRequiredProperties
		getEnvironment().validateRequiredProperties();

		// 3、缓存对预刷新应用事件感兴趣的监听器
		if (this.earlyApplicationListeners == null) {
			this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
		}
		else {
			// 4、将本地应用程序监听器重置为预刷新状态
			this.applicationListeners.clear();
			this.applicationListeners.addAll(this.earlyApplicationListeners);
		}

		// 5、允许收集ApplicationEvents（系统事件），
		//将在Multicast（广播器）可用后发布
		this.earlyApplicationEvents = new LinkedHashSet<>();
	}

//1.1
	@Override
	protected void initPropertySources() {
	    //先去获取容器上下文
		ConfigurableEnvironment env = getEnvironment();
		//判断 如果当前上下文环境属于 可配置的web环境
		if (env instanceof ConfigurableWebEnvironment) {
			//将servletContext与servletConfig加载到上下文环境中（一般情况下servletContext、servletConfig都为null）
			((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, null);
		}
	}

//2.1 演示定义必须存在的属性，设置后不存在的话 启动报错，可在application.properties中添加
import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.PropertySource;
import java.util.HashMap;
import java.util.Map;

@Order(1)
public class Firstinitializer  implements ApplicationContextInitializer {
    
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        ConfigurableEnvironment environment = applicationContext.getEnvironment();
        //约定必须存在的属性myRequestProperty
        environment.setRequiredProperties("myRequestProperty");
    }
}

obtainFreshBeanFactory

• 设置beanFactory序列化id
• 获取beanFactory

    //告诉子类刷新内部bean工厂
	protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
	    //1
		refreshBeanFactory();
		//2
		return getBeanFactory();
	}

    //1.1
	@Override
	protected final void refreshBeanFactory() throws IllegalStateException {
	    //设置refreshed属性为true，标明 当前正处于刷新
		if (!this.refreshed.compareAndSet(false, true)) {
			throw new IllegalStateException(
					"GenericApplicationContext does not support multiple refresh attempts: just call 'refresh' once");
		}
		//给beanFactory设置一个序列化的id
		this.beanFactory.setSerializationId(getId());
	}

	//2.1 返回此上下文持有的单个内部BeanFactory
	private final DefaultListableBeanFactory beanFactory;
	@Override
	public final ConfigurableListableBeanFactory getBeanFactory() {
		return this.beanFactory;
	}

prepareBeanFactory

• 设置beanFactory一些属性
• 添加后置处理器
• 设置忽略的自动装配接口
• 注册一些组件

	/**
	 * 配置工厂的标准上下文特征，
	 * 例如上下文的类加载器和后处理器
	 * @param beanFactory要配置的beanFactory
	 */
	protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		// 设置类加载器
		beanFactory.setBeanClassLoader(getClassLoader());
		if (!shouldIgnoreSpel) {
		    //设置解析器，主要用来解析SPEL表达式的，即：#{...}
			beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
		}
		//用来做属性转化使用的
		beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

		// 添加一个bean的后置处理器
		beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
		//忽略掉如下的所有该方法调用的入参定义类型的自动装配，他会交由ApplicationContextAwareProcessor来处理
		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.ignoreDependencyInterface(ApplicationStartupAware.class);

		// 向beanFactory添加一些解析依赖
		beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
		beanFactory.registerResolvableDependency(ResourceLoader.class, this);
		beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
		beanFactory.registerResolvableDependency(ApplicationContext.class, this);

		// 再添加一个bean的后置处理器
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

		// 如果发现了，检测LoadTimeWeaver并准备编织
		if (!NativeDetector.inNativeImage() && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
			beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
			// 为类型匹配设置临时类加载器
			beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
		}

		// 检查beanFactory中是否包含如下默认环境bean，不包含的话则注册默认环境bean
		if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
			beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
		}
		if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
			beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
		}
		if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
			beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
		}
		if (!beanFactory.containsLocalBean(APPLICATION_STARTUP_BEAN_NAME)) {
			beanFactory.registerSingleton(APPLICATION_STARTUP_BEAN_NAME, getApplicationStartup());
		}
	}

postProcessBeanFactory

• 子类重写以在BeanFactory完成创建后做进一步设置

    //org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#postProcessBeanFactory
	@Override
	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	    //1、调用父类的postProcessBeanFactory方法
		super.postProcessBeanFactory(beanFactory);
		if (this.basePackages != null && this.basePackages.length > 0) {
			this.scanner.scan(this.basePackages);
		}
		if (!this.annotatedClasses.isEmpty()) {
			this.reader.register(ClassUtils.toClassArray(this.annotatedClasses));
		}
	}

    //1.1
	@Override
	protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
	    //添加后置处理器
		beanFactory.addBeanPostProcessor(new WebApplicationContextServletContextAwareProcessor(this));
		//忽略ServletContextAware类型的装配处理接口
		beanFactory.ignoreDependencyInterface(ServletContextAware.class);
		//web应用的作用域和环境配置信息
		registerWebApplicationScopes();
	}

invokeBeanFactoryPostProcessors

• 调用BeanDefinitionRegistryPostProcessor实现向容器内添加bean的定义
• 调用BeanFactoryPostProcessor实现向容器内bean的定义添加属性

	/**
	 * 实例化并按order排序顺序调用所有已注册的BeanFactoryPostProcessor bean
	 * 必须在单例实例化之前调用
	 */
	protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
	    //getBeanFactoryPostProcessors() 方法获取beanFactoryPostProcessors对象实例
		    //invokeBeanFactoryPostProcessors执行所有BeanDefinitionRegistryPostProcessor实例的postProcessBeanDefinitionRegistry的方法调用   和    BeanFactoryPostProcessor对象实例的postProcessBeanFactory的方法调用
		PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
		if (!NativeDetector.inNativeImage() && beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
			beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
			beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
		}
	}

public static void invokeBeanFactoryPostProcessors(
			ConfigurableListableBeanFactory beanFactory, List beanFactoryPostProcessors) {

		// Invoke BeanDefinitionRegistryPostProcessors first, if any.
		Set processedBeans = new HashSet<>();

		if (beanFactory instanceof BeanDefinitionRegistry) {
			BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
			List regularPostProcessors = new ArrayList<>();
			List registryProcessors = new ArrayList<>();

			for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
				if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
					BeanDefinitionRegistryPostProcessor registryProcessor =
							(BeanDefinitionRegistryPostProcessor) postProcessor;
					registryProcessor.postProcessBeanDefinitionRegistry(registry);
					registryProcessors.add(registryProcessor);
				}
				else {
					regularPostProcessors.add(postProcessor);
				}
			}

			List currentRegistryProcessors = new ArrayList<>();

			// 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();

			// 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();

			// 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();
			}

			// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
			invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
			invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
		}

		else {
			// Invoke factory processors registered with the context instance.
			invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
		}

		// 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 priorityOrderedPostProcessors = new ArrayList<>();
		List orderedPostProcessorNames = new ArrayList<>();
		List 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);
			}
		}

		// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

		// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
		List orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
		for (String postProcessorName : orderedPostProcessorNames) {
			orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
		}
		sortPostProcessors(orderedPostProcessors, beanFactory);
		invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

		// Finally, invoke all other BeanFactoryPostProcessors.
		List nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
		for (String postProcessorName : nonOrderedPostProcessorNames) {
			nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
		}
		invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
		beanFactory.clearMetadataCache();
	}

拓展BeanFactoryPostProcessor的使用

@Component
public class Teacher {
    private String name;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

@Component
public class MyPostProcessor implements BeanFactoryPostProcessor {
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        BeanDefinition teacher = beanFactory.getBeanDefinition("teacher");
        MutablePropertyValues propertyValues = teacher.getPropertyValues();
        propertyValues.addPropertyValue("name", "wangwu");
    }
}

    @Autowired
    private Teacher teacher;
    @Test
    public void test3() {
        System.out.println(teacher.getName());
    }

consule：  wangwu

registerBeanPostProcessors

• 找到BeanProcessor的实现
• 排序后注册进容器内

	protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
	    //向beanFactory中注册BeanPostProcessors
		PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
	}

public static void registerBeanPostProcessors(
			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
			//中beanFactory中获得BeanPostProcessor的全类名
		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);

		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));

		List priorityOrderedPostProcessors = new ArrayList<>();
		List internalPostProcessors = new ArrayList<>();
		List orderedPostProcessorNames = new ArrayList<>();
		List nonOrderedPostProcessorNames = new ArrayList<>();
		//遍历 并将 BeanPostProcessor的实现添加在对应的集合
		for (String ppName : postProcessorNames) {
			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
				priorityOrderedPostProcessors.add(pp);
				if (pp instanceof MergedBeanDefinitionPostProcessor) {
					internalPostProcessors.add(pp);
				}
			}
			else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
				orderedPostProcessorNames.add(ppName);
			}
			else {
				nonOrderedPostProcessorNames.add(ppName);
			}
		}
	    //排序
		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
		//注册BeanPostProcessors 到 beanFactory中
		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);

		// Next, register the BeanPostProcessors that implement Ordered.
		List orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
		for (String ppName : orderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			orderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
		sortPostProcessors(orderedPostProcessors, beanFactory);
		registerBeanPostProcessors(beanFactory, orderedPostProcessors);

		// Now, register all regular BeanPostProcessors.
		List nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
		for (String ppName : nonOrderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			nonOrderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
		registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);

		// Finally, re-register all internal BeanPostProcessors.
		sortPostProcessors(internalPostProcessors, beanFactory);
		registerBeanPostProcessors(beanFactory, internalPostProcessors);

		// Re-register post-processor for detecting inner beans as ApplicationListeners,
		// moving it to the end of the processor chain (for picking up proxies etc).
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
	}

initMessageSource

• 初始化国际化相关属性

protected void initMessageSource() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		//判断beanFactory中是否包含MessageSource，如果不包含则创建并添加
		if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
			this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
			// Make MessageSource aware of parent MessageSource.
			if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
				HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
				if (hms.getParentMessageSource() == null) {
					// Only set parent context as parent MessageSource if no parent MessageSource
					// registered already.
					hms.setParentMessageSource(getInternalParentMessageSource());
				}
			}
			if (logger.isTraceEnabled()) {
				logger.trace("Using MessageSource [" + this.messageSource + "]");
			}
		}
		else {
			// Use empty MessageSource to be able to accept getMessage calls.
			DelegatingMessageSource dms = new DelegatingMessageSource();
			dms.setParentMessageSource(getInternalParentMessageSource());
			this.messageSource = dms;
			beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);
			if (logger.isTraceEnabled()) {
				logger.trace("No '" + MESSAGE_SOURCE_BEAN_NAME + "' bean, using [" + this.messageSource + "]");
			}
		}
	}

initApplicationEventMulticaster

• 初始化事件广播器

protected void initApplicationEventMulticaster() {
		ConfigurableListableBeanFactory beanFactory = getBeanFactory();
		//当前beanFactory中是否包含广播器的实现
		if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
			this.applicationEventMulticaster =
					beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
			if (logger.isTraceEnabled()) {
				logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
			}
		}
		else {
		    //不存在的话 构建一个 SimpleApplicationEventMulticaster的广播器实现
			this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
			beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
			if (logger.isTraceEnabled()) {
				logger.trace("No '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "' bean, using " +
						"[" + this.applicationEventMulticaster.getClass().getSimpleName() + "]");
			}
		}
	}

onRefresh

• 创建web容器

    //一个空实现，留给子类来实现
	protected void onRefresh() throws BeansException {
		// For subclasses: do nothing by default.
	}

如果是在web环境中 则调用 org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#onRefresh

	@Override
	protected void onRefresh() {
		super.onRefresh();
		try {
		    //构建web容器，如 tomcat、jette
			createWebServer();
		}
		catch (Throwable ex) {
			throw new ApplicationContextException("Unable to start web server", ex);
		}
	}

registerListeners

• 添加容器内事件监听器至事件广播器中
• 派发早期事件

    //向广播器添加监听器的实现
    protected void registerListeners() {
		// Register statically specified listeners first.
		for (ApplicationListener listener : getApplicationListeners()) {
			getApplicationEventMulticaster().addApplicationListener(listener);
		}

		// Do not initialize FactoryBeans here: We need to leave all regular beans
		// uninitialized to let post-processors apply to them!
		String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
		for (String listenerBeanName : listenerBeanNames) {
			getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
		}

		//当earlyApplicationEvents不为空的时候，将earlyApplicationEvents保存的时间依次广播出去
		//当事件已经产生，但是系统监听器还没有初始化完成的时候，就会将事假保存在earlyApplicationEvents集合中
		Set earlyEventsToProcess = this.earlyApplicationEvents;
		this.earlyApplicationEvents = null;
		if (!CollectionUtils.isEmpty(earlyEventsToProcess)) {
			for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
				getApplicationEventMulticaster().multicastEvent(earlyEvent);
			}
		}
	}

拓展 org.springframework.context.support.AbstractApplicationContext#publishEvent(java.lang.Object, org.springframework.core.ResolvableType)

   //该方法展示 earlyApplicationEvents不为null的时候，将事件 添加到 earlyApplicationEvents中
   //一直等到registerListeners方法调用，将监听器的实现添加到广播器后，将earlyApplicationEvents置位null
	protected void publishEvent(Object event, @Nullable ResolvableType eventType) {
		Assert.notNull(event, "Event must not be null");

		// Decorate event as an ApplicationEvent if necessary
		ApplicationEvent applicationEvent;
		if (event instanceof ApplicationEvent) {
			applicationEvent = (ApplicationEvent) event;
		}
		else {
			applicationEvent = new PayloadApplicationEvent<>(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 {
			getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType);
		}

		// Publish event via parent context as well...
		if (this.parent != null) {
			if (this.parent instanceof AbstractApplicationContext) {
				((AbstractApplicationContext) this.parent).publishEvent(event, eventType);
			}
			else {
				this.parent.publishEvent(event);
			}
		}
	}

finishBeanFactoryInitialization

• 初始化所有剩下的单实例bean
  查看如下的：bean实例化解析 中介绍

finishRefresh

• 初始化生命周期处理器
• 调用生命周期处理器onRefresh方法
• 发布ContextRefreshedEvent事件
• JMX相关处理

	@SuppressWarnings("deprecation")
	protected void finishRefresh() {
		// Clear context-level resource caches (such as ASM metadata from scanning).
		//清除上下文级别的资源缓存
		clearResourceCaches();

		/*......*/
		// Publish the final event.
		//发布最终事件
		publishEvent(new ContextRefreshedEvent(this));

		/*......*/
	}

bean实例化解析

BeanDefinition介绍
1、一个对象在Spring中描述，RootBeanDefinition是其常见实现
2、通过操作BeanDefinition来完成bean实例化和属性注入

实例化流程
start->getBean->doGetBean->getSingleton->CreateBean->resolveBeforeInstantiation->doCreateBean->createBeanInstance->instantiateBean->instantiate->populateBean->initializeBean->end

finishBeanFactoryInitialization

	protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
		/*......*/
		// 实例化单例bean
		beanFactory.preInstantiateSingletons();
	}

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

		// 获取所有beanDefinition的名字
		List beanNames = new ArrayList<>(this.beanDefinitionNames);

		//依次进行遍历
		for (String beanName : beanNames) {
		    //获取BeanDefinition，BeanDefinition是描述bean对象的元数据信息
			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
			//实例化满足 非抽象、单例、非延迟加载 三个条件的bean
			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
			    //1、isFactoryBean方法判断是否为工厂类
				if (isFactoryBean(beanName)) {
				    //是工厂类的haul，在beanName前加上工厂类的标志，再去调用getBean方法（FACTORY_BEAN_PREFIX = "&"）
					Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
					if (bean instanceof FactoryBean) {
						FactoryBean factory = (FactoryBean) bean;
						boolean isEagerInit;
						if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
							isEagerInit = AccessController.doPrivileged(
									(PrivilegedAction) ((SmartFactoryBean) factory)::isEagerInit,
									getAccessControlContext());
						}
						else {
							isEagerInit = (factory instanceof SmartFactoryBean &&
									((SmartFactoryBean) factory).isEagerInit());
						}
						if (isEagerInit) {
						    //2
							getBean(beanName);
						}
					}
				}
				else {
					getBean(beanName);
				}
			}
		}

		// Trigger post-initialization callback for all applicable beans...
		for (String beanName : beanNames) {
			Object singletonInstance = getSingleton(beanName);
			if (singletonInstance instanceof SmartInitializingSingleton) {
				StartupStep smartInitialize = this.getApplicationStartup().start("spring.beans.smart-initialize")
						.tag("beanName", beanName);
				SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
				if (System.getSecurityManager() != null) {
					AccessController.doPrivileged((PrivilegedAction