doc: BeanNameGenerator

docs/Spring/clazz/Spring-BeanNameGenerator.md

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+# Spring BeanNameGenerator
+- Author: [HuiFer](https://github.com/huifer)
+- 源码阅读仓库: [SourceHot-spring](https://github.com/SourceHot/spring-framework-read)
+
+
+- `org.springframework.beans.factory.support.BeanNameGenerator`
+- 方法用来生成 beanName
+
+
+```java
+public interface BeanNameGenerator {
+
+	/**
+	 * Generate a bean name for the given bean definition.
+	 * 生成 beanName
+	 * @param definition the bean definition to generate a name for
+	 * @param registry the bean definition registry that the given definition
+	 * is supposed to be registered with
+	 * @return the generated bean name
+	 */
+	String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry);
+
+}
+```
+
+
+
+![](/images/spring/BeanNameGenerator.png)
+
+
+
+
+
+## DefaultBeanNameGenerator
+
+- `org.springframework.beans.factory.support.DefaultBeanNameGenerator`
+
+
+
+- 调用工具类方法进行生成
+
+```JAVA
+@Override
+public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {
+   return BeanDefinitionReaderUtils.generateBeanName(definition, registry);
+}
+```
+
+
+
+1. ClassName + # + 十六进制字符
+2. parentName + $child + # + 十六进制字符
+3. factoryBeanName +$created+# + 十六进制字符
+4. beanName + # + 序号
+
+```java
+public static String generateBeanName(
+      BeanDefinition definition, BeanDefinitionRegistry registry, boolean isInnerBean)
+      throws BeanDefinitionStoreException {
+
+   // 获取 bean class 的名称
+   // Class.getName()
+   String generatedBeanName = definition.getBeanClassName();
+   if (generatedBeanName == null) {
+      // 父类名称是否存在
+      if (definition.getParentName() != null) {
+         generatedBeanName = definition.getParentName() + "$child";
+      }
+      // 工厂 beanName 是否为空
+      else if (definition.getFactoryBeanName() != null) {
+         generatedBeanName = definition.getFactoryBeanName() + "$created";
+      }
+   }
+   if (!StringUtils.hasText(generatedBeanName)) {
+      throw new BeanDefinitionStoreException("Unnamed bean definition specifies neither " +
+            "'class' nor 'parent' nor 'factory-bean' - can't generate bean name");
+   }
+
+   String id = generatedBeanName;
+   if (isInnerBean) {
+      // Inner bean: generate identity hashcode suffix.
+      // 组装名称
+      // 生成名称 + # + 16 进制的一个字符串
+      id = generatedBeanName + GENERATED_BEAN_NAME_SEPARATOR + ObjectUtils.getIdentityHexString(definition);
+   }
+   else {
+      // Top-level bean: use plain class name with unique suffix if necessary.
+      // 唯一beanName设置
+      // // beanName + # + 序号
+      return uniqueBeanName(generatedBeanName, registry);
+   }
+   return id;
+}
+```
+
+
+
+
+
+## AnnotationBeanNameGenerator
+
+1. 获取注解的value作为beanName
+2. 类名首字母小写
+
+```java
+@Override
+public String generateBeanName(BeanDefinition definition, BeanDefinitionRegistry registry) {
+   if (definition instanceof AnnotatedBeanDefinition) {
+      // 从注解中获取 beanName
+      // 获取注解的value属性值
+      String beanName = determineBeanNameFromAnnotation((AnnotatedBeanDefinition) definition);
+      if (StringUtils.hasText(beanName)) {
+         // Explicit bean name found.
+         // 如果存在直接返回
+         return beanName;
+      }
+   }
+   // Fallback: generate a unique default bean name.
+   // 默认beanName
+   // 类名,首字母小写
+   return buildDefaultBeanName(definition, registry);
+}
+```
+
+
+
+
+
+## FullyQualifiedAnnotationBeanNameGenerator
+
+- 全类名
+
+```java
+@Override
+protected String buildDefaultBeanName(BeanDefinition definition) {
+   String beanClassName = definition.getBeanClassName();
+   Assert.state(beanClassName != null, "No bean class name set");
+   return beanClassName;
+}
+```