/**
* @author hskw
* @version 1.0.0
* @Description TODO
* @createTime 2019-11-16
*/
public class Test {
public static void main(String[] args) {
AnnotationConfigApplicationContext ac = new AnnotationConfigApplicationContext();
ac.register(Appconfig.class);
ac.refresh();
IndexService indexService = ac.getBean(IndexService.class);
System.out.println(indexService.getIndexService1());
}
}
package org.springframework.context.annotation;
/**
* Spring中出来注解Bean定义的类有两个：
* AnnotationConfigApplicationContext和
* AnnotationConfigWebApplicationContex。
* nnotationConfigWebApplicationContext
* 是AnnotationConfigApplicationContext的web版本
* 两者的用法以及对注解的处理方式几乎没有什么差别
* 通过分析这个类我们知道注册一个bean到spring容器有两种办法
* 一、直接将注解Bean注册到容器中：（参考）public void register(Class<?>... annotatedClasses)
* 但是直接把一个注解的bean注册到容器当中也分为两种方法
* 1、在初始化容器时注册并且解析
* 2、也可以在容器创建之后手动调用注册方法向容器注册，然后通过手动刷新容器，使得容器对注册的注解Bean进行处理。
* 思考：为什么@profile要使用这类的第2种方法
*
* 二、通过扫描指定的包及其子包下的所有类
* 扫描其实同上，也是两种方法，初始化的时候扫描，和初始化之后再扫描
*
* @author Juergen Hoeller
* @author Chris Beams
* @since 3.0
* @see #register
* @see #scan
* @see AnnotatedBeanDefinitionReader
* @see ClassPathBeanDefinitionScanner
* @see org.springframework.context.support.GenericXmlApplicationContext
*/
public class AnnotationConfigApplicationContext extends GenericApplicationContext implements AnnotationConfigRegistry {
/**
* 这个类顾名思义是一个reader，一个读取器
* 读取什么呢？还是顾名思义AnnotatedBeanDefinition意思是读取一个被加了注解的bean
* 这个类在构造方法中实例化的
*/
private final AnnotatedBeanDefinitionReader reader;
/**
* 同意顾名思义，这是一个扫描器，扫描所有加了注解的bean
* 同样是在构造方法中被实例化的
*/
private final ClassPathBeanDefinitionScanner scanner;
/**
* 初始化一个bean的读取和扫描器
* 何谓读取器和扫描器参考上面的属性注释
* 默认构造函数，如果直接调用这个默认构造方法，需要在稍后通过调用其register()
* 去注册配置类（javaconfig），并调用refresh()方法刷新容器，
* 触发容器对注解Bean的载入、解析和注册过程
* 这种使用过程我在ioc应用的第二节课讲@profile的时候讲过
* Create a new AnnotationConfigApplicationContext that needs to be populated
* through {@link #register} calls and then manually {@linkplain #refresh refreshed}.
*/
public AnnotationConfigApplicationContext() {
/**
* 父类的构造方法
* 创建一个读取注解的Bean定义读取器
* 什么是bean定义？BeanDefinition
*
* AnnotatedBeanDefinitionReader:
* 1、解析加了@Configuration注解的类
* 2、通过ac.register(xxx.class)注册的也由它来解析
*/
this.reader = new AnnotatedBeanDefinitionReader(this);
//可以用来扫描包或者类，继而转换成bd
//提供API让程序员能够在外部调用AnnotationConfigApplicationContext对象的scan方法
//这个scanner，Spring内部没有使用
this.scanner = new ClassPathBeanDefinitionScanner(this);
}
/**
* Create a new AnnotationConfigApplicationContext with the given DefaultListableBeanFactory.
* @param beanFactory the DefaultListableBeanFactory instance to use for this context
*/
public AnnotationConfigApplicationContext(DefaultListableBeanFactory beanFactory) {
super(beanFactory);
this.reader = new AnnotatedBeanDefinitionReader(this);
this.scanner = new ClassPathBeanDefinitionScanner(this);
}
/**
* 这个构造方法需要传入一个被javaconfig注解了的配置类
* 然后会把这个被注解了javaconfig的类通过注解读取器读取后继而解析
* Create a new AnnotationConfigApplicationContext, deriving bean definitions
* from the given annotated classes and automatically refreshing the context.
* @param annotatedClasses one or more annotated classes,
* e.g. {@link Configuration @Configuration} classes
*/
public AnnotationConfigApplicationContext(Class<?>... annotatedClasses) {
//annotatedClasses appconfig.class
//这里由于他有父类，故而会先调用父类的构造方法，然后才会调用自己的构造方法
//在自己构造方法中初始一个读取器和扫描器
this();
//this.beanDefinitionMap.put(beanName, beanDefinition);
register(annotatedClasses);
refresh();
}
/**
* Create a new AnnotationConfigApplicationContext, scanning for bean definitions
* in the given packages and automatically refreshing the context.
* @param basePackages the packages to check for annotated classes
*/
public AnnotationConfigApplicationContext(String... basePackages) {
this();
scan(basePackages);
refresh();
}
/**
* Propagates the given custom {@code Environment} to the underlying
* {@link AnnotatedBeanDefinitionReader} and {@link ClassPathBeanDefinitionScanner}.
*/
@Override
public void setEnvironment(ConfigurableEnvironment environment) {
super.setEnvironment(environment);
this.reader.setEnvironment(environment);
this.scanner.setEnvironment(environment);
}
/**
* Provide a custom {@link BeanNameGenerator} for use with {@link AnnotatedBeanDefinitionReader}
* and/or {@link ClassPathBeanDefinitionScanner}, if any.
* <p>Default is {@link org.springframework.context.annotation.AnnotationBeanNameGenerator}.
* <p>Any call to this method must occur prior to calls to {@link #register(Class...)}
* and/or {@link #scan(String...)}.
* @see AnnotatedBeanDefinitionReader#setBeanNameGenerator
* @see ClassPathBeanDefinitionScanner#setBeanNameGenerator
*/
public void setBeanNameGenerator(BeanNameGenerator beanNameGenerator) {
this.reader.setBeanNameGenerator(beanNameGenerator);
this.scanner.setBeanNameGenerator(beanNameGenerator);
getBeanFactory().registerSingleton(
AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR, beanNameGenerator);
}
/**
* Set the {@link ScopeMetadataResolver} to use for detected bean classes.
* <p>The default is an {@link AnnotationScopeMetadataResolver}.
* <p>Any call to this method must occur prior to calls to {@link #register(Class...)}
* and/or {@link #scan(String...)}.
*/
public void setScopeMetadataResolver(ScopeMetadataResolver scopeMetadataResolver) {
this.reader.setScopeMetadataResolver(scopeMetadataResolver);
this.scanner.setScopeMetadataResolver(scopeMetadataResolver);
}
//---------------------------------------------------------------------
// Implementation of AnnotationConfigRegistry
//---------------------------------------------------------------------
/**
* 注册单个bean给容器
* 比如有新加的类可以用这个方法
* 但是注册Bean之后需要手动调用refresh方法去触发容器解析注解
*
* 有两个意思
* 他可以注册一个配置类
* 他还可以单独注册一个bean
* Register one or more annotated classes to be processed.
* <p>Note that {@link #refresh()} must be called in order for the context
* to fully process the new classes.
* @param annotatedClasses one or more annotated classes,
* e.g. {@link Configuration @Configuration} classes
* @see #scan(String...)
* @see #refresh()
*/
public void register(Class<?>... annotatedClasses) {
Assert.notEmpty(annotatedClasses, "At least one annotated class must be specified");
this.reader.register(annotatedClasses);
}
/**
* Perform a scan within the specified base packages.
* <p>Note that {@link #refresh()} must be called in order for the context
* to fully process the new classes.
* @param basePackages the packages to check for annotated classes
* @see #register(Class...)
* @see #refresh()
*/
public void scan(String... basePackages) {
Assert.notEmpty(basePackages, "At least one base package must be specified");
this.scanner.scan(basePackages);
}
//---------------------------------------------------------------------
// Convenient methods for registering individual beans
//---------------------------------------------------------------------
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations, and optionally providing explicit constructor
* arguments for consideration in the autowiring process.
* <p>The bean name will be generated according to annotated component rules.
* @param annotatedClass the class of the bean
* @param constructorArguments argument values to be fed into Spring's
* constructor resolution algorithm, resolving either all arguments or just
* specific ones, with the rest to be resolved through regular autowiring
* (may be {@code null} or empty)
* @since 5.0
*/
public <T> void registerBean(Class<T> annotatedClass, Object... constructorArguments) {
registerBean(null, annotatedClass, constructorArguments);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations, and optionally providing explicit constructor
* arguments for consideration in the autowiring process.
* @param beanName the name of the bean (may be {@code null})
* @param annotatedClass the class of the bean
* @param constructorArguments argument values to be fed into Spring's
* constructor resolution algorithm, resolving either all arguments or just
* specific ones, with the rest to be resolved through regular autowiring
* (may be {@code null} or empty)
* @since 5.0
*/
public <T> void registerBean(@Nullable String beanName, Class<T> annotatedClass, Object... constructorArguments) {
this.reader.doRegisterBean(annotatedClass, null, beanName, null,
bd -> {
for (Object arg : constructorArguments) {
bd.getConstructorArgumentValues().addGenericArgumentValue(arg);
}
});
}
@Override
public <T> void registerBean(@Nullable String beanName, Class<T> beanClass, @Nullable Supplier<T> supplier,
BeanDefinitionCustomizer... customizers) {
this.reader.doRegisterBean(beanClass, supplier, beanName, null, customizers);
}
}
/**
* Create a new GenericApplicationContext.
* @see #registerBeanDefinition
* @see #refresh
* 实例化一个工厂DefaultListableBeanFactory
*/
public GenericApplicationContext() {
this.beanFactory = new DefaultListableBeanFactory();
}
/**
* Spring's default implementation of the {@link ConfigurableListableBeanFactory}
* and {@link BeanDefinitionRegistry} interfaces: a full-fledged bean factory
* based on bean definition metadata, extensible through post-processors.
*
* <p>Typical usage is registering all bean definitions first (possibly read
* from a bean definition file), before accessing beans. Bean lookup by name
* is therefore an inexpensive operation in a local bean definition table,
* operating on pre-resolved bean definition metadata objects.
*
* <p>Note that readers for specific bean definition formats are typically
* implemented separately rather than as bean factory subclasses:
* see for example {@link PropertiesBeanDefinitionReader} and
* {@link org.springframework.beans.factory.xml.XmlBeanDefinitionReader}.
*
* <p>For an alternative implementation of the
* {@link org.springframework.beans.factory.ListableBeanFactory} interface,
* have a look at {@link StaticListableBeanFactory}, which manages existing
* bean instances rather than creating new ones based on bean definitions.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @author Sam Brannen
* @author Costin Leau
* @author Chris Beams
* @author Phillip Webb
* @author Stephane Nicoll
* @since 16 April 2001
* @see #registerBeanDefinition
* @see #addBeanPostProcessor
* @see #getBean
* @see #resolveDependency
*/
@SuppressWarnings("serial")
public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory
implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable {
@Nullable
private static Class<?> javaxInjectProviderClass;
static {
try {
javaxInjectProviderClass =
ClassUtils.forName("javax.inject.Provider", DefaultListableBeanFactory.class.getClassLoader());
}
catch (ClassNotFoundException ex) {
// JSR-330 API not available - Provider interface simply not supported then.
javaxInjectProviderClass = null;
}
}
/** Map from serialized id to factory instance */
private static final Map<String, Reference<DefaultListableBeanFactory>> serializableFactories =
new ConcurrentHashMap<>(8);
/** Optional id for this factory, for serialization purposes */
@Nullable
private String serializationId;
/** Whether to allow re-registration of a different definition with the same name */
private boolean allowBeanDefinitionOverriding = true;
/** Whether to allow eager class loading even for lazy-init beans */
private boolean allowEagerClassLoading = true;
/** Optional OrderComparator for dependency Lists and arrays */
@Nullable
private Comparator<Object> dependencyComparator;
/** Resolver to use for checking if a bean definition is an autowire candidate */
private AutowireCandidateResolver autowireCandidateResolver = new SimpleAutowireCandidateResolver();
/** Map from dependency type to corresponding autowired value */
private final Map<Class<?>, Object> resolvableDependencies = new ConcurrentHashMap<>(16);
/** Map of bean definition objects, keyed by bean name */
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<>(256);
/** Map of singleton and non-singleton bean names, keyed by dependency type */
private final Map<Class<?>, String[]> allBeanNamesByType = new ConcurrentHashMap<>(64);
/** Map of singleton-only bean names, keyed by dependency type */
private final Map<Class<?>, String[]> singletonBeanNamesByType = new ConcurrentHashMap<>(64);
/** List of bean definition names, in registration order */
private volatile List<String> beanDefinitionNames = new ArrayList<>(256);
/** List of names of manually registered singletons, in registration order */
private volatile Set<String> manualSingletonNames = new LinkedHashSet<>(16);
/** Cached array of bean definition names in case of frozen configuration */
@Nullable
private volatile String[] frozenBeanDefinitionNames;
/** Whether bean definition metadata may be cached for all beans */
private volatile boolean configurationFrozen = false;
/**
* Create a new DefaultListableBeanFactory.
*/
public DefaultListableBeanFactory() {
super();
}
/**
* Create a new DefaultListableBeanFactory with the given parent.
* @param parentBeanFactory the parent BeanFactory
*/
public DefaultListableBeanFactory(@Nullable BeanFactory parentBeanFactory) {
super(parentBeanFactory);
}
}
package org.springframework.context.annotation;
public class AnnotatedBeanDefinitionReader {
private final BeanDefinitionRegistry registry;
private BeanNameGenerator beanNameGenerator = new AnnotationBeanNameGenerator();
private ScopeMetadataResolver scopeMetadataResolver = new AnnotationScopeMetadataResolver();
private ConditionEvaluator conditionEvaluator;
/**
* Create a new {@code AnnotatedBeanDefinitionReader} for the given registry.
* If the registry is {@link EnvironmentCapable}, e.g. is an {@code ApplicationContext},
* the {@link Environment} will be inherited, otherwise a new
* {@link StandardEnvironment} will be created and used.
* @param registry the {@code BeanFactory} to load bean definitions into,
* in the form of a {@code BeanDefinitionRegistry}
* @see #AnnotatedBeanDefinitionReader(BeanDefinitionRegistry, Environment)
* @see #setEnvironment(Environment)
*/
/**
* 这里的BeanDefinitionRegistry registry是通过在AnnotationConfigApplicationContext
* 的构造方法中传进来的this
* 由此说明AnnotationConfigApplicationContext是一个BeanDefinitionRegistry类型的类
* 何以证明我们可以看到AnnotationConfigApplicationContext的类关系：
* GenericApplicationContext extends AbstractApplicationContext implements BeanDefinitionRegistry
* 看到他实现了BeanDefinitionRegistry证明上面的说法，那么BeanDefinitionRegistry的作用是什么呢？
* BeanDefinitionRegistry 顾名思义就是BeanDefinition的注册器
* 那么何为BeanDefinition呢？参考BeanDefinition的源码的注释
* @param registry
*/
public AnnotatedBeanDefinitionReader(BeanDefinitionRegistry registry) {
this(registry, getOrCreateEnvironment(registry));
}
/**
* Create a new {@code AnnotatedBeanDefinitionReader} for the given registry and using
* the given {@link Environment}.
* @param registry the {@code BeanFactory} to load bean definitions into,
* in the form of a {@code BeanDefinitionRegistry}
* @param environment the {@code Environment} to use when evaluating bean definition
* profiles.
* @since 3.1
*/
public AnnotatedBeanDefinitionReader(BeanDefinitionRegistry registry, Environment environment) {
// Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
// Assert.notNull(environment, "Environment must not be null");
this.registry = registry;
this.conditionEvaluator = new ConditionEvaluator(registry, environment, null);
// 委托AnnotationConfigUtils
AnnotationConfigUtils.registerAnnotationConfigProcessors(this.registry);
}
/**
* Return the BeanDefinitionRegistry that this scanner operates on.
*/
public final BeanDefinitionRegistry getRegistry() {
return this.registry;
}
/**
* Set the Environment to use when evaluating whether
* {@link Conditional @Conditional}-annotated component classes should be registered.
* <p>The default is a {@link StandardEnvironment}.
* @see #registerBean(Class, String, Class...)
*/
public void setEnvironment(Environment environment) {
this.conditionEvaluator = new ConditionEvaluator(this.registry, environment, null);
}
/**
* Set the BeanNameGenerator to use for detected bean classes.
* <p>The default is a {@link AnnotationBeanNameGenerator}.
*/
public void setBeanNameGenerator(@Nullable BeanNameGenerator beanNameGenerator) {
this.beanNameGenerator = (beanNameGenerator != null ? beanNameGenerator : new AnnotationBeanNameGenerator());
}
/**
* Set the ScopeMetadataResolver to use for detected bean classes.
* <p>The default is an {@link AnnotationScopeMetadataResolver}.
*/
public void setScopeMetadataResolver(@Nullable ScopeMetadataResolver scopeMetadataResolver) {
this.scopeMetadataResolver =
(scopeMetadataResolver != null ? scopeMetadataResolver : new AnnotationScopeMetadataResolver());
}
/**
* Register one or more annotated classes to be processed.
* <p>Calls to {@code register} are idempotent; adding the same
* annotated class more than once has no additional effect.
* @param annotatedClasses one or more annotated classes,
* e.g. {@link Configuration @Configuration} classes
*/
public void register(Class<?>... annotatedClasses) {
for (Class<?> annotatedClass : annotatedClasses) {
registerBean(annotatedClass);
}
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations.
* @param annotatedClass the class of the bean
*/
public void registerBean(Class<?> annotatedClass) {
doRegisterBean(annotatedClass, null, null, null);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations, using the given supplier for obtaining a new
* instance (possibly declared as a lambda expression or method reference).
* @param annotatedClass the class of the bean
* @param instanceSupplier a callback for creating an instance of the bean
* (may be {@code null})
* @since 5.0
*/
public <T> void registerBean(Class<T> annotatedClass, @Nullable Supplier<T> instanceSupplier) {
doRegisterBean(annotatedClass, instanceSupplier, null, null);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations, using the given supplier for obtaining a new
* instance (possibly declared as a lambda expression or method reference).
* @param annotatedClass the class of the bean
* @param name an explicit name for the bean
* @param instanceSupplier a callback for creating an instance of the bean
* (may be {@code null})
* @since 5.0
*/
public <T> void registerBean(Class<T> annotatedClass, String name, @Nullable Supplier<T> instanceSupplier) {
doRegisterBean(annotatedClass, instanceSupplier, name, null);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations.
* @param annotatedClass the class of the bean
* @param qualifiers specific qualifier annotations to consider,
* in addition to qualifiers at the bean class level
*/
@SuppressWarnings("unchecked")
public void registerBean(Class<?> annotatedClass, Class<? extends Annotation>... qualifiers) {
doRegisterBean(annotatedClass, null, null, qualifiers);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations.
* @param annotatedClass the class of the bean
* @param name an explicit name for the bean
* @param qualifiers specific qualifier annotations to consider,
* in addition to qualifiers at the bean class level
*/
@SuppressWarnings("unchecked")
public void registerBean(Class<?> annotatedClass, String name, Class<? extends Annotation>... qualifiers) {
doRegisterBean(annotatedClass, null, name, qualifiers);
}
/**
* Register a bean from the given bean class, deriving its metadata from
* class-declared annotations.
* @param annotatedClass the class of the bean
* @param instanceSupplier a callback for creating an instance of the bean
* (may be {@code null})
* @param name an explicit name for the bean
* @param qualifiers specific qualifier annotations to consider, if any,
* in addition to qualifiers at the bean class level
* @param definitionCustomizers one or more callbacks for customizing the
* factory's {@link BeanDefinition}, e.g. setting a lazy-init or primary flag
* @since 5.0
*/
<T> void doRegisterBean(Class<T> annotatedClass, @Nullable Supplier<T> instanceSupplier, @Nullable String name,
@Nullable Class<? extends Annotation>[] qualifiers, BeanDefinitionCustomizer... definitionCustomizers) {
/**
* 根据指定的bean创建一个AnnotatedGenericBeanDefinition
* 这个AnnotatedGenericBeanDefinition可以理解为一个数据结构
* AnnotatedGenericBeanDefinition包含了类的其他信息,比如一些元信息
* scope，lazy等等
*/
AnnotatedGenericBeanDefinition abd = new AnnotatedGenericBeanDefinition(annotatedClass);
/**
* 判断这个类是否需要跳过解析
* 通过代码可以知道spring判断是否跳过解析，主要判断类有没有加注解
*/
if (this.conditionEvaluator.shouldSkip(abd.getMetadata())) {
return;
}
//不知道
abd.setInstanceSupplier(instanceSupplier);
/**
* 得到类的作用域
*/
ScopeMetadata scopeMetadata = this.scopeMetadataResolver.resolveScopeMetadata(abd);
/**
* 把类的作用域添加到数据结构结构中
*/
abd.setScope(scopeMetadata.getScopeName());
/**
* 生成类的名字通过beanNameGenerator记得布置过一个作业
*/
String beanName = (name != null ? name : this.beanNameGenerator.generateBeanName(abd, this.registry));
/**
* 处理类当中的通用注解
* 分析源码可以知道他主要处理
* Lazy DependsOn Primary Role等等注解
* 处理完成之后processCommonDefinitionAnnotations中依然是把他添加到数据结构当中
*
*/
AnnotationConfigUtils.processCommonDefinitionAnnotations(abd);
/**
* 如果在向容器注册注解Bean定义时，使用了额外的限定符注解则解析
* 关于Qualifier和Primary前面的课当中讲过，主要涉及到spring的自动装配
* 这里需要注意的
* byName和qualifiers这个变量是Annotation类型的数组，里面存不仅仅是Qualifier注解
* 理论上里面里面存的是一切注解，所以可以看到下面的代码spring去循环了这个数组
* 然后依次判断了注解当中是否包含了Primary，是否包含了Lazyd
*/
if (qualifiers != null) {
for (Class<? extends Annotation> qualifier : qualifiers) {
////如果配置了@Primary注解，如果加了则作为首选
if (Primary.class == qualifier) {
abd.setPrimary(true);
}
//懒加载，前面加过
else if (Lazy.class == qualifier) {
abd.setLazyInit(true);
}
else {
//如果使用了除@Primary和@Lazy以外的其他注解，则为该Bean添加一个根据名字自动装配的限定符
//这里难以理解，后面会详细介绍
abd.addQualifier(new AutowireCandidateQualifier(qualifier));
}
}
}
for (BeanDefinitionCustomizer customizer : definitionCustomizers) {
customizer.customize(abd);
}
/**
* 这个BeanDefinitionHolder也是一个数据结构
*/
BeanDefinitionHolder definitionHolder = new BeanDefinitionHolder(abd, beanName);
/**
* ScopedProxyMode 这个知识点比较复杂，需要结合web去理解
* 可以暂时放一下，等说道springmvc的时候再说
* 或者看情况现在说也是一样的
*/
definitionHolder = AnnotationConfigUtils.applyScopedProxyMode(scopeMetadata, definitionHolder, this.registry);
/**
* 把上述的这个数据结构注册给registry
* registy就是AnnotatonConfigApplicationContext
* AnnotatonConfigApplicationContext在初始化的時候通過調用父類的構造方法
* 實例化了一个DefaultListableBeanFactory
* *registerBeanDefinition里面就是把definitionHolder这个数据结构包含的信息注册到
* DefaultListableBeanFactory这个工厂
*/
BeanDefinitionReaderUtils.registerBeanDefinition(definitionHolder, this.registry);
}
/**
* Get the Environment from the given registry if possible, otherwise return a new
* StandardEnvironment.
*/
private static Environment getOrCreateEnvironment(BeanDefinitionRegistry registry) {
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
if (registry instanceof EnvironmentCapable) {
return ((EnvironmentCapable) registry).getEnvironment();
}
return new StandardEnvironment();
}
}
package org.springframework.context.annotation;
public class AnnotationConfigUtils {
/**
* The bean name of the internally managed Configuration annotation processor.
*/
public static final String CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME =
"org.springframework.context.annotation.internalConfigurationAnnotationProcessor";
/**
* The bean name of the internally managed BeanNameGenerator for use when processing
* {@link Configuration} classes. Set by {@link AnnotationConfigApplicationContext}
* and {@code AnnotationConfigWebApplicationContext} during bootstrap in order to make
* any custom name generation strategy available to the underlying
* {@link ConfigurationClassPostProcessor}.
* @since 3.1.1
*/
public static final String CONFIGURATION_BEAN_NAME_GENERATOR =
"org.springframework.context.annotation.internalConfigurationBeanNameGenerator";
/**
* The bean name of the internally managed Autowired annotation processor.
*/
public static final String AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME =
"org.springframework.context.annotation.internalAutowiredAnnotationProcessor";
/**
* The bean name of the internally managed Required annotation processor.
*/
public static final String REQUIRED_ANNOTATION_PROCESSOR_BEAN_NAME =
"org.springframework.context.annotation.internalRequiredAnnotationProcessor";
/**
* The bean name of the internally managed JSR-250 annotation processor.
*/
public static final String COMMON_ANNOTATION_PROCESSOR_BEAN_NAME =
"org.springframework.context.annotation.internalCommonAnnotationProcessor";
/**
* The bean name of the internally managed JPA annotation processor.
*/
public static final String PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME =
"org.springframework.context.annotation.internalPersistenceAnnotationProcessor";
private static final String PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME =
"org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor";
/**
* The bean name of the internally managed @EventListener annotation processor.
*/
public static final String EVENT_LISTENER_PROCESSOR_BEAN_NAME =
"org.springframework.context.event.internalEventListenerProcessor";
/**
* The bean name of the internally managed EventListenerFactory.
*/
public static final String EVENT_LISTENER_FACTORY_BEAN_NAME =
"org.springframework.context.event.internalEventListenerFactory";
private static final boolean jsr250Present =
ClassUtils.isPresent("javax.annotation.Resource", AnnotationConfigUtils.class.getClassLoader());
private static final boolean jpaPresent =
ClassUtils.isPresent("javax.persistence.EntityManagerFactory", AnnotationConfigUtils.class.getClassLoader()) &&
ClassUtils.isPresent(PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME, AnnotationConfigUtils.class.getClassLoader());
/**
* Register all relevant annotation post processors in the given registry.
* @param registry the registry to operate on
*/
public static void registerAnnotationConfigProcessors(BeanDefinitionRegistry registry) {
registerAnnotationConfigProcessors(registry, null);
}
/**
* Register all relevant annotation post processors in the given registry.
* @param registry the registry to operate on
* @param source the configuration source element (already extracted)
* that this registration was triggered from. May be {@code null}.
* @return a Set of BeanDefinitionHolders, containing all bean definitions
* that have actually been registered by this call
*/
public static Set<BeanDefinitionHolder> registerAnnotationConfigProcessors(
BeanDefinitionRegistry registry, @Nullable Object source) {
DefaultListableBeanFactory beanFactory = unwrapDefaultListableBeanFactory(registry);
if (beanFactory != null) {
if (!(beanFactory.getDependencyComparator() instanceof AnnotationAwareOrderComparator)) {
//AnnotationAwareOrderComparator主要能解析@Order注解和@Priority，主要去排序
beanFactory.setDependencyComparator(AnnotationAwareOrderComparator.INSTANCE);
}
if (!(beanFactory.getAutowireCandidateResolver() instanceof ContextAnnotationAutowireCandidateResolver)) {
//ContextAnnotationAutowireCandidateResolver提供处理延迟加载的功能
beanFactory.setAutowireCandidateResolver(new ContextAnnotationAutowireCandidateResolver());
}
}
/**
* 往BeanDefinitionMap注册一个ConfigurationClassPostProcessor?
* org.springframework.context.annotation.internalConfigurationAnnotationProcessor
* why?因为需要在invokeBeanFactoryPostProcessors中获取
* invokeBeanFactoryPostProcessors主要是在spring的beanFactory初始化的过程中去做一些事情，怎么来做这些事情呢？
* 委托了多个实现了BeanDefinitionRegistryPostProcessor或者BeanFactoryProcessor接口的类来做这些事情,有自定义的也有spring内部的
* 其中ConfigurationClassPostProcessor就是一个spring内部的BeanDefinitionRegistryPostProcessor
* 因为如果你不添加这里就没有办法委托ConfigurationClassPostProcessor做一些功能
* 到底哪些功能？参考下面的注释
*/
Set<BeanDefinitionHolder> beanDefs = new LinkedHashSet<>(8);
//BeanDefinitio的注册，这里很重要，需要理解注册每个bean的类型（5个BeanPostProcessor和1个BeanFactoryPostProcessor）
if (!registry.containsBeanDefinition(CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME)) {
//需要注意的是ConfigurationClassPostProcessor的类型是BeanDefinitionRegistryPostProcessor
//而 BeanDefinitionRegistryPostProcessor 最终实现BeanFactoryPostProcessor这个接口
RootBeanDefinition def = new RootBeanDefinition(ConfigurationClassPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, CONFIGURATION_ANNOTATION_PROCESSOR_BEAN_NAME));
}
if (!registry.containsBeanDefinition(AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME)) {
//AutowiredAnnotationBeanPostProcessor 实现了 MergedBeanDefinitionPostProcessor
//MergedBeanDefinitionPostProcessor 最终实现了 BeanPostProcessor
RootBeanDefinition def = new RootBeanDefinition(AutowiredAnnotationBeanPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, AUTOWIRED_ANNOTATION_PROCESSOR_BEAN_NAME));
}
if (!registry.containsBeanDefinition(REQUIRED_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(RequiredAnnotationBeanPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, REQUIRED_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// Check for JSR-250 support, and if present add the CommonAnnotationBeanPostProcessor.
if (jsr250Present && !registry.containsBeanDefinition(COMMON_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(CommonAnnotationBeanPostProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, COMMON_ANNOTATION_PROCESSOR_BEAN_NAME));
}
// Check for JPA support, and if present add the PersistenceAnnotationBeanPostProcessor.
// String PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME =
// "org.springframework.context.annotation.internalPersistenceAnnotationProcessor";
if (jpaPresent && !registry.containsBeanDefinition(PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition();
try {
def.setBeanClass(ClassUtils.forName(PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME,
AnnotationConfigUtils.class.getClassLoader()));
}
catch (ClassNotFoundException ex) {
throw new IllegalStateException(
"Cannot load optional framework class: " + PERSISTENCE_ANNOTATION_PROCESSOR_CLASS_NAME, ex);
}
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, PERSISTENCE_ANNOTATION_PROCESSOR_BEAN_NAME));
}
if (!registry.containsBeanDefinition(EVENT_LISTENER_PROCESSOR_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(EventListenerMethodProcessor.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_PROCESSOR_BEAN_NAME));
}
if (!registry.containsBeanDefinition(EVENT_LISTENER_FACTORY_BEAN_NAME)) {
RootBeanDefinition def = new RootBeanDefinition(DefaultEventListenerFactory.class);
def.setSource(source);
beanDefs.add(registerPostProcessor(registry, def, EVENT_LISTENER_FACTORY_BEAN_NAME));
}
return beanDefs;
}
private static BeanDefinitionHolder registerPostProcessor(
BeanDefinitionRegistry registry, RootBeanDefinition definition, String beanName) {
definition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
registry.registerBeanDefinition(beanName, definition);
return new BeanDefinitionHolder(definition, beanName);
}
@Nullable
private static DefaultListableBeanFactory unwrapDefaultListableBeanFactory(BeanDefinitionRegistry registry) {
if (registry instanceof DefaultListableBeanFactory) {
return (DefaultListableBeanFactory) registry;
}
else if (registry instanceof GenericApplicationContext) {
//这里在AnnotationConfigApplicationContext初始化的时候this()
//方法中调用了父类GenericApplicationContext的时候new了一个DefaultListableBeanFactory对象
//下面代码返回这个对象
return ((GenericApplicationContext) registry).getDefaultListableBeanFactory();
}
else {
return null;
}
}
public static void processCommonDefinitionAnnotations(AnnotatedBeanDefinition abd) {
processCommonDefinitionAnnotations(abd, abd.getMetadata());
}
/**
* 检查常用的注解
* @param abd
* @param metadata
*/
static void processCommonDefinitionAnnotations(AnnotatedBeanDefinition abd, AnnotatedTypeMetadata metadata) {
AnnotationAttributes lazy = attributesFor(metadata, Lazy.class);
if (lazy != null) {
abd.setLazyInit(lazy.getBoolean("value"));
}
else if (abd.getMetadata() != metadata) {
lazy = attributesFor(abd.getMetadata(), Lazy.class);
if (lazy != null) {
abd.setLazyInit(lazy.getBoolean("value"));
}
}
if (metadata.isAnnotated(Primary.class.getName())) {
abd.setPrimary(true);
}
AnnotationAttributes dependsOn = attributesFor(metadata, DependsOn.class);
if (dependsOn != null) {
abd.setDependsOn(dependsOn.getStringArray("value"));
}
if (abd instanceof AbstractBeanDefinition) {
AbstractBeanDefinition absBd = (AbstractBeanDefinition) abd;
AnnotationAttributes role = attributesFor(metadata, Role.class);
if (role != null) {
absBd.setRole(role.getNumber("value").intValue());
}
AnnotationAttributes description = attributesFor(metadata, Description.class);
if (description != null) {
absBd.setDescription(description.getString("value"));
}
}
}
static BeanDefinitionHolder applyScopedProxyMode(
ScopeMetadata metadata, BeanDefinitionHolder definition, BeanDefinitionRegistry registry) {
ScopedProxyMode scopedProxyMode = metadata.getScopedProxyMode();
if (scopedProxyMode.equals(ScopedProxyMode.NO)) {
return definition;
}
boolean proxyTargetClass = scopedProxyMode.equals(ScopedProxyMode.TARGET_CLASS);
return ScopedProxyCreator.createScopedProxy(definition, registry, proxyTargetClass);
}
@Nullable
static AnnotationAttributes attributesFor(AnnotatedTypeMetadata metadata, Class<?> annotationClass) {
return attributesFor(metadata, annotationClass.getName());
}
@Nullable
static AnnotationAttributes attributesFor(AnnotatedTypeMetadata metadata, String annotationClassName) {
return AnnotationAttributes.fromMap(metadata.getAnnotationAttributes(annotationClassName, false));
}
static Set<AnnotationAttributes> attributesForRepeatable(AnnotationMetadata metadata,
Class<?> containerClass, Class<?> annotationClass) {
return attributesForRepeatable(metadata, containerClass.getName(), annotationClass.getName());
}
@SuppressWarnings("unchecked")
static Set<AnnotationAttributes> attributesForRepeatable(
AnnotationMetadata metadata, String containerClassName, String annotationClassName) {
Set<AnnotationAttributes> result = new LinkedHashSet<>();
// Direct annotation present?
addAttributesIfNotNull(result, metadata.getAnnotationAttributes(annotationClassName, false));
// Container annotation present?
Map<String, Object> container = metadata.getAnnotationAttributes(containerClassName, false);
if (container != null && container.containsKey("value")) {
for (Map<String, Object> containedAttributes : (Map<String, Object>[]) container.get("value")) {
addAttributesIfNotNull(result, containedAttributes);
}
}
// Return merged result
return Collections.unmodifiableSet(result);
}
private static void addAttributesIfNotNull(
Set<AnnotationAttributes> result, @Nullable Map<String, Object> attributes) {
if (attributes != null) {
result.add(AnnotationAttributes.fromMap(attributes));
}
}
}
@Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
// 准备工作包括设置启动时间，是否激活标识位，
// 初始化属性源(property source)配置
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
//返回一个beanFactory 为什么需要返回一个工厂
//因为要对工厂进行初始化
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
//准备工厂
//1、添加一个类加载器
//2、添加bean表达式解释器，为了能够让我们的beanFactory去解析bean表达式
//3、添加一个后置处理器ApplicationContextAwareProcessor
//4、添加了自动注入被忽略的列表
//5、......
//6、添加了一个ApplicationListenerDetector后置处理器（自行百度）
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
//这个方法在当前版本的spring是没用任何代码的
//可能spring期待在后面的版本中去扩展吧
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
//在spring的环境中去执行已经被注册的 factory processors
//设置执行自定义的ProcessBeanFactory 和spring内部自己定义的
//完成了所谓的扫描 和 parse（类————>BeanDefinition）
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
//注册beanPostProcessor
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
initMessageSource();
// Initialize event multicaster for this context.
//初始化应用事件广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// 检查监听器bean并注册它们。
registerListeners();
// 实例化所有剩余（非延迟初始化）单例。
// 剩下的就是Spring添加的后置处理器和扫描的我们提供的类
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// Destroy already created singletons to avoid dangling resources.
destroyBeans();
// Reset 'active' flag.
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}
/**
* Prepare this context for refreshing, setting its startup date and
* active flag as well as performing any initialization of property sources.
*/
protected void prepareRefresh() {
this.startupDate = System.currentTimeMillis();
this.closed.set(false);
this.active.set(true);
if (logger.isInfoEnabled()) {
logger.info("Refreshing " + this);
}
// Initialize any placeholder property sources in the context environment
//这个方法目前没有子类去实现
//估计spring是期待后面的版本有子类去实现吧
initPropertySources();
// Validate that all properties marked as required are resolvable
// see ConfigurablePropertyResolver#setRequiredProperties
getEnvironment().validateRequiredProperties();
// Allow for the collection of early ApplicationEvents,
// to be published once the multicaster is available...
this.earlyApplicationEvents = new LinkedHashSet<>();
}
/**
*
* 配置其标准的特征，比如上下文的加载器ClassLoader和post-processors回调
* Configure the factory's standard context characteristics,
* such as the context's ClassLoader and post-processors.
* @param beanFactory the BeanFactory to configure
* 此处的beanFactory参数等于DefaultListableFactory
*/
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
beanFactory.setBeanClassLoader(getClassLoader());
//bean表达式解释器，后面说 能够获取bean当中的属性在前台页面
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
//对象与string类型的转换 <property ref="dao">把这个ref指向的dao字符串转换成对象
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
//添加一个后置管理器
//ApplicationContextAwareProcessor
// 能够在bean中获得到各种*Aware（*Aware都有其作用）
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
//添加了自动注入被忽略的列表
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 interface not registered as resolvable type in a plain factory.
// MessageSource registered (and found for autowiring) as a bean.
// 依赖替换
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
// Register early post-processor for detecting inner beans as ApplicationListeners.
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
// Detect a LoadTimeWeaver and prepare for weaving, if found.
if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
// Set a temporary ClassLoader for type matching.
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
//意思是如果自定义的Bean中没有名为"systemProperties"和"systemEnvironment"的Bean，
// 则注册两个Bena，Key为"systemProperties"和"systemEnvironment"，Value为Map，
// 这两个Bean就是一些系统配置和系统环境信息
// 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());
}
}
/**
* Instantiate and invoke all registered BeanPostProcessor beans,
* respecting explicit order if given.
* <p>Must be called before any instantiation of application beans.
*/
protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
}
/**
* Initialize the MessageSource.
* Use parent's if none defined in this context.
*/
protected void initMessageSource() {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
//查找是否包含了名为messageSource的bean，如果没有，创建一个默认的
if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
// Make MessageSource aware of parent MessageSource.
//判断是否有父类且是一个分层级的messageSource，如果是将父容器的的messageSource设置到里边
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.isDebugEnabled()) {
logger.debug("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.isDebugEnabled()) {
logger.debug("Unable to locate MessageSource with name '" + MESSAGE_SOURCE_BEAN_NAME +
"': using default [" + this.messageSource + "]");
}
}
}
