有两个实现版本，DefaultBeanNameGenerator和AnnotationBeanNameGenerator。其中DefaultBeanNameGenerator是给资源文件加载bean时使用（BeanDefinitionReader中使用）；AnnotationBeanNameGenerator是为了处理注解生成bean name的情况。
public class DefaultBeanNameGenerator implements BeanNameGenerator { /** * A convenient constant for a default {@code DefaultBeanNameGenerator} instance, * as used for {@link AbstractBeanDefinitionReader} setup. * @since 5.2 */ public static final DefaultBeanNameGenerator INSTANCE = new DefaultBeanNameGenerator(); @Override public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) { return BeanDefinitionReaderUtils.generateBeanName(definition, registry); }}DefaultBeanNameGenerator类将具体的处理方式委托给了，BeanDefinitionReaderUtils 中的generateBeanName(BeanDefinition, BeanDefinitionRegistry)方法处理。
//org.springframework.beans.factory.support.BeanDefinitionReaderUtilspublic static String generateBeanName(BeanDefinition beanDefinition, BeanDefinitionRegistry registry)throws BeanDefinitionStoreException {return generateBeanName(beanDefinition, registry, false);}//多指定了一个boolean型参数，是为了区分内部bean(innerBean）和顶级bean（top-level bean).public static String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry, boolean isInnerBean)throws BeanDefinitionStoreException {//generatedBeanName定义为类前缀,读取bean的className,不一定是运行时的实际类型。String generatedBeanName = definition.getBeanClassName();//如果类名称为空if (generatedBeanName == null) { if (definition.getParentName() != null) {//读取bean的parent bean namegeneratedBeanName = definition.getParentName() + "$child";}else if (definition.getFactoryBeanName() != null) {//读取生成该bean的factoryBean name名称做前缀generatedBeanName = definition.getFactoryBeanName() + "$created";}}//generatedBeanName为空字符串,抛出异常if (!StringUtils.hasText(generatedBeanName)) {throw new BeanDefinitionStoreException("Unnamed bean definition specifies neither " +"'class' nor 'parent' nor 'factory-bean' - can't generate bean name");}//当为内部bean时，调用系统底层的object唯一标识码生成if (isInnerBean) {// Inner bean: generate identity hashcode suffix.return generatedBeanName + GENERATED_BEAN_NAME_SEPARATOR + ObjectUtils.getIdentityHexString(definition);}//否则即为顶级bean,生成策略是前缀+循环数字,直到找到没有被注册的id作为后缀// Top-level bean: use plain class name with unique suffix if necessary.return uniqueBeanName(generatedBeanName, registry);}/**将给定bean名称转换为给定bean工厂的惟一bean名称，必要时附加惟一计数器作为后缀。*/public static String uniqueBeanName(String beanName, BeanDefinitionRegistry registry) {String id = beanName;int counter = -1;// Increase counter until the id is unique.String prefix = beanName + GENERATED_BEAN_NAME_SEPARATOR;while (counter == -1 || registry.containsBeanDefinition(id)) {counter++;id = prefix + counter;}return id;}public class AnnotationBeanNameGenerator implements BeanNameGenerator { public static final AnnotationBeanNameGenerator INSTANCE = new AnnotationBeanNameGenerator(); private static final String COMPONENT_ANNOTATION_CLASSNAME = "org.springframework.stereotype.Component"; private final Map> metaAnnotationTypesCache = new ConcurrentHashMap<>(); @Override public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) { /** * 判断是否是否是AnnotatedBeanDefinition的子类， AnnotatedBeanDefinition是BeanDefinition的一个子类 * 如果是AnnotatedBeanDefinition ， 按照注解生成模式生成信息，否则生成默认的bean name */ if (definition instanceof AnnotatedBeanDefinition) { String beanName = determineBeanNameFromAnnotation((AnnotatedBeanDefinition) definition); /** 保证生成的bean name 非空 */ if (StringUtils.hasText(beanName)) { // Explicit bean name found. return beanName; } } // Fallback: generate a unique default bean name. return buildDefaultBeanName(definition, registry); }/** * 从类的注解中包含value属性的注解生成一个bean name * @param annotatedDef * @return */@Nullableprotected String determineBeanNameFromAnnotation(AnnotatedBeanDefinition annotatedDef) { /** 获取注解类元信息 */AnnotationMetadata amd = annotatedDef.getMetadata();/** 一个类存在多个注解，故类型为集合*/Set types = amd.getAnnotationTypes();String beanName = null;for (String type : types) { /** 获取该类型对应的属性 */AnnotationAttributes attributes = AnnotationConfigUtils.attributesFor(amd, type);if (attributes != null) {Set metaTypes = this.metaAnnotationTypesCache.computeIfAbsent(type, key -> {Set result = amd.getMetaAnnotationTypes(key);return (result.isEmpty() ? Collections.emptySet() : result);});/** 判断注解类型是否包含value属性 */if (isStereotypeWithNameValue(type, metaTypes, attributes)) {Object value = attributes.get("value");if (value instanceof String) {String strVal = (String) value;if (StringUtils.hasLength(strVal)) { /** 基本不会在此逻辑 */if (beanName != null && !strVal.equals(beanName)) {throw new IllegalStateException("Stereotype annotations suggest inconsistent " +"component names: '" + beanName + "' versus '" + strVal + "'");}beanName = strVal;}}}}}return beanName;}protected String buildDefaultBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {return buildDefaultBeanName(definition);}protected String buildDefaultBeanName(BeanDefinition definition) {String beanClassName = definition.getBeanClassName();Assert.state(beanClassName != null, "No bean class name set");/** 根据传入字符串获取一个具体类名称，不含包路径，考虑cglib代理的类，做了一个特殊处理。 */String shortClassName = ClassUtils.getShortName(beanClassName);return Introspector.decapitalize(shortClassName);}} 生成bean name有两条处理线，使用AnnotationBeanDefinition注解和不使用的。
不使用AnnotationBeanDefinition注解：直接将类名（不含包名）改为驼峰形式作为bean name。
使用AnnotationBeanDefinition注解的：
AnnotationConfigApplicationContext在初始化的时候，可以设置bean生成策略器，放入单例池中；
org.springframework.context.annotation.ConfigurationClassPostProcessor#processConfigBeanDefinitions方法中会进行bean策略器赋值，如果从单例池中根据默认名称获取到对应的beancel器则进行赋值，覆盖掉默认的bean策略器；
public static final String CONFIGURATION_BEAN_NAME_GENERATOR = "org.springframework.context.annotation.internalConfigurationBeanNameGenerator";/* Using short class names as default bean names by default. */private BeanNameGenerator componentScanBeanNameGenerator = AnnotationBeanNameGenerator.INSTANCE;public static final AnnotationBeanNameGenerator INSTANCE = new AnnotationBeanNameGenerator();| 留言与评论（共有 0 条评论） “” |
