自定义BeanNameGenerator生成规则-编程知识

自定义BeanNameGenerator生成规则

通过点进ComponentScan注解进入源码可以看到

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追随BeanNameGenerator进入源码可以看到该类是个借口且只有一个方法

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点击上面黑色箭头出现两个实现方法

点击第一个方法

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进入determineBeanNameFromAnnotation方法中

通过上诉自定义一个生成beanName方法

先创建一个CustomeBeanNameGenerator类
实现BeanNameGenerator接口
重写generateBeanName方法

public class CustomeBeanNameGenerator implements BeanNameGenerator {@Overridepublic String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {//定义Bean的名称String beanName = null;//1.判断当前bean的定义信息是否是注解的if(definition instanceof AnnotatedBeanDefinition){//2.把definition转成注解的bean定义信息AnnotatedBeanDefinition annotatedBeanDefinition = (AnnotatedBeanDefinition)definition;//2.获取注解Bean定义的元信息AnnotationMetadata annotationMetadata = annotatedBeanDefinition.getMetadata();//3.获取定义信息中的所有注解Set<String> types = annotationMetadata.getAnnotationTypes();//4.遍历types集合for(String type : types){//5.得到注解的属性AnnotationAttributes attributes = AnnotationAttributes.fromMap(annotationMetadata.getAnnotationAttributes(type, false));//6.判断attributes是否为null，同时必须是@Component及其衍生注解if (attributes != null && isStereotypeWithNameValue(type, annotationMetadata.getMetaAnnotationTypes(type), attributes)) {//7.获取value属性的值Object value = attributes.get("value");//8.判断value属性是否为String类型if (value instanceof String) {String strVal = (String) value;//9.判断value属性是否有值if (StringUtils.hasLength(strVal)) {if (beanName != null && !strVal.equals(beanName)) {throw new IllegalStateException("Stereotype annotations suggest inconsistent " +"component names: '" + beanName + "' versus '" + strVal + "'");}beanName = strVal;}}}}}return beanName != null ? "my"+beanName : "my"+buildDefaultBeanName(definition);}private static final String COMPONENT_ANNOTATION_CLASSNAME = "org.springframework.stereotype.Component";private boolean isStereotypeWithNameValue(String annotationType,Set<String> metaAnnotationTypes, @Nullable Map<String, Object> attributes) {boolean isStereotype = annotationType.equals(COMPONENT_ANNOTATION_CLASSNAME) ||metaAnnotationTypes.contains(COMPONENT_ANNOTATION_CLASSNAME) ||annotationType.equals("javax.annotation.ManagedBean") ||annotationType.equals("javax.inject.Named");return (isStereotype && attributes != null && attributes.containsKey("value"));}private 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);}
}