单一类型依赖查找-BeanFactory

• 根据Bean名称查找
  • getBean(String)
  • Spring 2.5覆盖默认参数：getBean(String,Object...)
• 根据Bean类型查找
  • Bean实时查找
    • Spring3.0 getBean(Class)
    • Spring 4.1覆盖默认参数：getBean(Class,Object)
  • Spring 5.1 Bean延迟查找
    • getBeanProvider(Class)

public class ObjectProviderDemo {
         public static void main(String[] args) {
         //创建BeanFactory容器
         AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
         //ObjectProviderDemo Class(配置类)
         applicationContext.register(ObjectProviderDemo.class);
         //启动spring应用上下文
         applicationContext.refresh();
         //依赖查找集合
         lookupByObjectProvider(applicationContext);
         //显示的关闭spring应用上下文
         applicationContext.close();
         }
        
         @Bean
         public String helloWorld(){ //方法名就是Bean名称 = "helloWorld"
         return "hello world";
         }
        
         private static void lookupByObjectProvider(AnnotationConfigApplicationContext applicationContext) {
         ObjectProvider<String> beanProvider = applicationContext.getBeanProvider(String.class);
         System.out.println(beanProvider.getObject());
         }
        }

    *   getBeanProvider(ResolvableType)

• 根据Bean名称+类型查找：getBean(String,Class)

集合类型依赖查找

集合类型查找接口-ListableBeanFactory

• 根据Bean类型查找
  • 获取同类型Bean名称列表
    • getBeanNamesForType(Class)
    • Spring 4.2 getBeanNamesForType(ResovleType)
  • 获取同类型Bean实例列表
    • getBeansOfType(Class)以及重载方法
• 通过注解类型查找
  • Spring 3.0 获取标注类型Bean名称列表
    • getBeanNamesForAnnotation(Class<? extends Annotation>)
  • Spring 3.0 获取标注类型Bean实例列表
    • getBeansWithAnnotation(Class<? Extends Annotation>)
  • Spring 3.0 获取指定名称 + 标注类型Bean实例
    • findAnnotationOnBean(String,Class<? extends Annotation>)
      根据之前（见Spring Bean深入剖析）对于ListableBeanFactory的介绍，我们可以得出结论：它是针对某一个类型去查找一个集合列表，集合列表可能有两种情况，一种是查询这个Bean的名称，一种情况是查询Bean的实例，推荐使用Bean的名称去判断这个Bean是否存在，当然，重要的方式是判断BeanDefinition是否存在，这种方式会避免Bean的提早的初始化，产生一些不确定的因素。
      层次性依赖查找
      层次性依赖查找接口-HierachicalBeanFactory

public interface HierarchicalBeanFactory extends BeanFactory {
 /**
 * Return the parent bean factory, or {@code null} if there is none.
 */
 @Nullable
 BeanFactory getParentBeanFactory();
 /**
 * Return whether the local bean factory contains a bean of the given name,
 * ignoring beans defined in ancestor contexts.
 * <p>This is an alternative to {@code containsBean}, ignoring a bean
 * of the given name from an ancestor bean factory.
 * @param name the name of the bean to query
 * @return whether a bean with the given name is defined in the local factory
 * @see BeanFactory#containsBean
 */
 boolean containsLocalBean(String name);

}

• 双亲BeanFactory：getParenetBeanFactroy()

 public static void main(String[] args) {
     //创建BeanFactory容器
     AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
     //ObjectProviderDemo Class(配置类)
     applicationContext.register(ObjectProviderDemo.class);
     //获取 HierarchicalBeanFactory <- ConfigurableBeanFactory <-ConfigurableListableBeanFactory
     ConfigurableListableBeanFactory beanFactory = applicationContext.getBeanFactory();
     System.out.println("当前 BeanFactory 的 Parent BeanFactory ：" + beanFactory.getParentBeanFactory());
     //设置 Parent BeanFactory
     HierarchicalBeanFactory parentBeanFactory = createParentBeanFactory();
     beanFactory.setParentBeanFactory(parentBeanFactory);
     System.out.println("当前 BeanFactory 的 Parent BeanFactory ：" + beanFactory.getParentBeanFactory());
     //启动spring应用上下文
     applicationContext.refresh();
     //显示的关闭spring应用上下文
     applicationContext.close();
     }
    
     private static ConfigurableListableBeanFactory createParentBeanFactory(){
     DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
     XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
     String location = "classpath:/META-INF/dependecy-lookup-context.xml";
     reader.loadBeanDefinitions(location);
     return beanFactory;
     }

• 层次性查找
  • 根据Bean的名称查找
    • 基于containsLocalBean方法实现

public class HierarchicalDependencyLookupDemo {
         public static void main(String[] args) {
         //创建BeanFactory容器
         AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
         //ObjectProviderDemo Class(配置类)
         applicationContext.register(ObjectProviderDemo.class);
         //获取 HierarchicalBeanFactory <- ConfigurableBeanFactory <-ConfigurableListableBeanFactory
         ConfigurableListableBeanFactory beanFactory = applicationContext.getBeanFactory();
         System.out.println("当前 BeanFactory 的 Parent BeanFactory ：" + beanFactory.getParentBeanFactory());
         //设置 Parent BeanFactory
         HierarchicalBeanFactory parentBeanFactory = createParentBeanFactory();
         beanFactory.setParentBeanFactory(parentBeanFactory);
         System.out.println("当前 BeanFactory 的 Parent BeanFactory ：" + beanFactory.getParentBeanFactory());
        
         displayLocalBean(beanFactory,"user");
         displayLocalBean(parentBeanFactory,"user");
         displayContainsBean(beanFactory,"user");
         displayContainsBean(parentBeanFactory,"user");
         //启动spring应用上下文
         applicationContext.refresh();
         //显示的关闭spring应用上下文
         applicationContext.close();
         }  
         private static void displayContainsBean(HierarchicalBeanFactory beanFactory,String beanName){
         System.out.printf("当前 BeanFactory [s%] 是否包含 Local bean[ name : s%]\n",beanFactory,beanName);
         containsBean(beanFactory,beanName);
         }
         private static boolean containsBean(HierarchicalBeanFactory beanFactory,String beanName){
         BeanFactory parentBeanFactory = beanFactory.getParentBeanFactory();
         if(parentBeanFactory instanceof HierarchicalBeanFactory){
         HierarchicalBeanFactory parentHierarchicalBeanFactory = HierarchicalBeanFactory.class.cast(parentBeanFactory);
         if(containsBean(parentHierarchicalBeanFactory,beanName)){
         return true;
         }
         }
         return beanFactory.containsLocalBean(beanName);
         }
        
         private static void displayLocalBean(HierarchicalBeanFactory beanFactory,String beanName){
         System.out.printf("当前 BeanFactory [s%] 是否包含 Local bean[ name : s%]\n",beanFactory,beanName);
         }
        
         private static ConfigurableListableBeanFactory createParentBeanFactory(){
         DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
         XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
         String location = "classpath:/META-INF/dependecy-lookup-context.xml";
         reader.loadBeanDefinitions(location);
         return beanFactory;
         }
        }

• 根据Bean类型查找实例列表
  • 单一类型：BeanFactoryUtils#beanOfType
  • 集合类型：BeanFactoryUtils#beansOfTypeIncludingAncestors
• 根据Java注解查找名称列表
  • BeansFactoryUtils#beanNamesForTypeIncluingAncestors