BeanNameGenerator

概要

Spring提供的BeanNameGenerator接口有3个实现：

org.springframework.beans.factory.support.BeanNameGenerator 无beanName的注解类实现: org.springframework.context.annotation.AnnotationBeanNameGenerator 无beanName的XML配置实现: org.springframework.beans.factory.support.DefaultBeanNameGenerator

DefaultBeanNameGenerator

BeanClass+#+0

    public static String generateBeanName(
            BeanDefinition definition, BeanDefinitionRegistry registry, boolean isInnerBean)
            throws BeanDefinitionStoreException {
        String generatedBeanName = definition.getBeanClassName();
        if (generatedBeanName == null) {
            if (definition.getParentName() != null) {
                generatedBeanName = definition.getParentName() + "$child";
            }
            else if (definition.getFactoryBeanName() != null) {
                generatedBeanName = definition.getFactoryBeanName() + "$created";
            }
        }
        if (!StringUtils.hasText(generatedBeanName)) {
            throw new BeanDefinitionStoreException("Unnamed bean definition specifies neither " +
                    "'class' nor 'parent' nor 'factory-bean' - can't generate bean name");
        }
        if (isInnerBean) {
            // Inner bean: generate identity hashcode suffix.
            return generatedBeanName + GENERATED_BEAN_NAME_SEPARATOR + ObjectUtils.getIdentityHexString(definition);
        }
        // Top-level bean: use plain class name with unique suffix if necessary.
        return uniqueBeanName(generatedBeanName, registry);
    }
    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; // 这个常量表示#
        while (counter == -1 || registry.containsBeanDefinition(id)) {
            counter++;
            id = prefix + counter;
        }
        return id;
    }

举个栗子

com.example.start.springdemo.spring.HelloWorldBeanPostProcessor#0

AnnotationBeanNameGenerator

当前类的短名称首字母小写

    protected String buildDefaultBeanName(BeanDefinition definition) {
        String beanClassName = definition.getBeanClassName();
        Assert.state(beanClassName != null, "No bean class name set");
        String shortClassName = ClassUtils.getShortName(beanClassName);
        return Introspector.decapitalize(shortClassName);
    }