ListableBeanFactory接口

朴灿烈づ我的快乐病毒、 2023-08-17 16:04 25阅读 0赞

在这里插入图片描述
ListableBeanFactory获取bean时,Spring 鼓励使用这个接口定义的api. 还有个Beanfactory方便使用.其他的4个接口都是不鼓励使用的.

提供容器中bean迭代的功能,不再需要一个个bean地查找.比如可以一次获取全部的bean(太暴力了),根据类型获取bean.在看SpringMVC时,扫描包路径下的具体实现策略就是使用的这种方式(那边使用的是BeanFactoryUtils封装的api).

如果同时实现了HierarchicalBeanFactory,返回值不会考虑父类BeanFactory,只考虑当前factory定义的类.当然也可以使用BeanFactoryUtils辅助类来查找祖先工厂中的类. 即ListableBeanFactory是beanFactory接口的扩展接口，它可以枚举所有的bean实例，而不是客户端通过名称一个一个的查询得出所有的实例。要预加载所有的bean定义的beanfactory可以实现这个接口来。该 接口定义了访问容器中Bean基本信息的若干方法，如查看Bean的个数、获取某一类型Bean的配置名、查看容器中是否包括某一Bean等方法.

这个接口中的方法只会考虑本factory定义的bean.这些方法会忽略ConfigurableBeanFactory的registerSingleton注册的单例bean(getBeanNamesOfType和getBeansOfType是例外,一样会考虑手动注册的单例).当然BeanFactory的getBean一样可以透明访问这些特殊bean.当然在典型情况下,所有的bean都是由external bean定义,所以应用不需要顾虑这些差别.

注意:getBeanDefinitionCount和containsBeanDefinition的实现方法因为效率比较低,还是少用为好.
ListableBeanFactory源码具体：

1、3个跟BeanDefinition有关的总体操作。包括BeanDefinition的总数、名字的集合、指定类型的名字的集合。（这里指出，BeanDefinition是Spring中非常重要的一个类，每个BeanDefinition实例都包含一个类在Spring工厂中所有属性。）

2、2个getBeanNamesForType重载方法。根据指定类型（包括子类）获取其对应的所有Bean名字。

3、2个getBeansOfType重载方法。根据类型（包括子类）返回指定Bean名和Bean的Map。

4、2个跟注解查找有关的方法。根据注解类型，查找Bean名和Bean的Map。以及根据指定Bean名和注解类型查找指定的Bean。

总结：

正如这个工厂接口的名字所示，这个工厂接口最大的特点就是可以列出工厂可以生产的所有实例。当然，工厂并没有直接提供返回所有实例的方法，也没这个必要。它可以返回指定类型的所有的实例。而且你可以通过getBeanDefinitionNames()得到工厂所有bean的名字，然后根据这些名字得到所有的Bean。这个工厂接口扩展了BeanFactory的功能，作为上文指出的BeanFactory二级接口，有9个独有的方法，扩展了跟BeanDefinition的功能，提供了BeanDefinition、BeanName、注解有关的各种操作。它可以根据条件返回Bean的集合，这就是它名字的由来——ListableBeanFactory。

  1. /** * * @author DemoTransfer * @since 4.3 */
  2. public interface ListableBeanFactory extends BeanFactory { 
  5.     //-------------------------------------------------------------------------
  6.     // 暴力获取全部bean的属性
  7.     //-------------------------------------------------------------------------
  9.     /** * Check if this bean factory contains a bean definition with the given name. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @param beanName the name of the bean to look for * @return if this bean factory contains a bean definition with the given name * @see #containsBean */
  10.     // 对于给定的名字是否含有BeanDefinition
  11.     boolean containsBeanDefinition(String beanName);
  13.     /** * Return the number of beans defined in the factory. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @return the number of beans defined in the factory */
  14.     // 返回工厂的BeanDefinition总数
  15.     int getBeanDefinitionCount();
  17.     /** * Return the names of all beans defined in this factory. * <p>Does not consider any hierarchy this factory may participate in, * and ignores any singleton beans that have been registered by * other means than bean definitions. * @return the names of all beans defined in this factory, * or an empty array if none defined */
  18.     // 返回工厂中所有Bean的名字
  19.     String[] getBeanDefinitionNames();
  21.     //-------------------------------------------------------------------------
  22.     // 根据bean 的类型获取bean
  23.     //
  24.     // 这边的方法仅检查顶级bean.它不会检查嵌套的bean.FactoryBean创建的bean会匹配为FactoryBean而不是原始类型.
  25.     // 一样不会考虑父factory中的bean,非要用可以通过BeanFactoryUtils中的beanNamesForTypeIncludingAncestors.
  26.     // 其他方式注册的单例这边会纳入判断.
  27.     // 这个版本的getBeanNamesForType会匹配所有类型的bean,包括单例,原型,FactoryBean.返回的bean names会根据backend 配置的进行排序.
  28.     //-------------------------------------------------------------------------
  30.     /** * Return the names of beans matching the given type (including subclasses), * judging from either bean definitions or the value of {@code getObjectType} * in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans, which means that FactoryBeans * will get initialized. If the object created by the FactoryBean doesn't match, * the raw FactoryBean itself will be matched against the type. * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils' {@code beanNamesForTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>This version of {@code getBeanNamesForType} matches all kinds of beans, * be it singletons, prototypes, or FactoryBeans. In most implementations, the * result will be the same as for {@code getBeanNamesForType(type, true, true)}. * <p>Bean names returned by this method should always return bean names <i>in the * order of definition</i> in the backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all bean names * @return the names of beans (or objects created by FactoryBeans) matching * the given object type (including subclasses), or an empty array if none * @since 4.2 * @see #isTypeMatch(String, ResolvableType) * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, ResolvableType) */
  31.     String[] getBeanNamesForType(ResolvableType type);
  33.     /** * Return the names of beans matching the given type (including subclasses), * judging from either bean definitions or the value of {@code getObjectType} * in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans, which means that FactoryBeans * will get initialized. If the object created by the FactoryBean doesn't match, * the raw FactoryBean itself will be matched against the type. * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils' {@code beanNamesForTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>This version of {@code getBeanNamesForType} matches all kinds of beans, * be it singletons, prototypes, or FactoryBeans. In most implementations, the * result will be the same as for {@code getBeanNamesForType(type, true, true)}. * <p>Bean names returned by this method should always return bean names <i>in the * order of definition</i> in the backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all bean names * @return the names of beans (or objects created by FactoryBeans) matching * the given object type (including subclasses), or an empty array if none * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, Class) */
  34.     // 获取给定类型的bean names(包括子类),通过bean 定义或者FactoryBean的getObjectType判断.
  35.     // 返回对于指定类型Bean（包括子类）的所有名字
  36.     String[] getBeanNamesForType(Class<?> type);
  38.     /** * Return the names of beans matching the given type (including subclasses), * judging from either bean definitions or the value of {@code getObjectType} * in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans if the "allowEagerInit" flag is set, * which means that FactoryBeans will get initialized. If the object created by the * FactoryBean doesn't match, the raw FactoryBean itself will be matched against the * type. If "allowEagerInit" is not set, only raw FactoryBeans will be checked * (which doesn't require initialization of each FactoryBean). * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils' {@code beanNamesForTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>Bean names returned by this method should always return bean names <i>in the * order of definition</i> in the backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all bean names * @param includeNonSingletons whether to include prototype or scoped beans too * or just singletons (also applies to FactoryBeans) * @param allowEagerInit whether to initialize <i>lazy-init singletons</i> and * <i>objects created by FactoryBeans</i> (or by factory methods with a * "factory-bean" reference) for the type check. Note that FactoryBeans need to be * eagerly initialized to determine their type: So be aware that passing in "true" * for this flag will initialize FactoryBeans and "factory-bean" references. * @return the names of beans (or objects created by FactoryBeans) matching * the given object type (including subclasses), or an empty array if none * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beanNamesForTypeIncludingAncestors(ListableBeanFactory, Class, boolean, boolean) */
  39.      /* * 返回指定类型的名字 includeNonSingletons为false表示只取单例Bean，true则不是 * allowEagerInit为true表示立刻加载，false表示延迟加载。 注意：FactoryBeans都是立刻加载的。 */
  40.     String[] getBeanNamesForType(Class<?> type, boolean includeNonSingletons, boolean allowEagerInit);
  42.     /** * Return the bean instances that match the given object type (including * subclasses), judging from either bean definitions or the value of * {@code getObjectType} in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans, which means that FactoryBeans * will get initialized. If the object created by the FactoryBean doesn't match, * the raw FactoryBean itself will be matched against the type. * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils' {@code beansOfTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>This version of getBeansOfType matches all kinds of beans, be it * singletons, prototypes, or FactoryBeans. In most implementations, the * result will be the same as for {@code getBeansOfType(type, true, true)}. * <p>The Map returned by this method should always return bean names and * corresponding bean instances <i>in the order of definition</i> in the * backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all concrete beans * @return a Map with the matching beans, containing the bean names as * keys and the corresponding bean instances as values * @throws BeansException if a bean could not be created * @since 1.1.2 * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beansOfTypeIncludingAncestors(ListableBeanFactory, Class) */
  43.     // 如果保护懒加载的类,FactoryBean初始化的类和工厂方法初始化的类会被初始化.就是说执行这个方法会执行对应的初始化.
  44.     // 根据类型（包括子类）返回指定Bean名和Bean的Map
  45.     <T> Map<String, T> getBeansOfType(Class<T> type) throws BeansException;
  47.     /** * Return the bean instances that match the given object type (including * subclasses), judging from either bean definitions or the value of * {@code getObjectType} in the case of FactoryBeans. * <p><b>NOTE: This method introspects top-level beans only.</b> It does <i>not</i> * check nested beans which might match the specified type as well. * <p>Does consider objects created by FactoryBeans if the "allowEagerInit" flag is set, * which means that FactoryBeans will get initialized. If the object created by the * FactoryBean doesn't match, the raw FactoryBean itself will be matched against the * type. If "allowEagerInit" is not set, only raw FactoryBeans will be checked * (which doesn't require initialization of each FactoryBean). * <p>Does not consider any hierarchy this factory may participate in. * Use BeanFactoryUtils' {@code beansOfTypeIncludingAncestors} * to include beans in ancestor factories too. * <p>Note: Does <i>not</i> ignore singleton beans that have been registered * by other means than bean definitions. * <p>The Map returned by this method should always return bean names and * corresponding bean instances <i>in the order of definition</i> in the * backend configuration, as far as possible. * @param type the class or interface to match, or {@code null} for all concrete beans * @param includeNonSingletons whether to include prototype or scoped beans too * or just singletons (also applies to FactoryBeans) * @param allowEagerInit whether to initialize <i>lazy-init singletons</i> and * <i>objects created by FactoryBeans</i> (or by factory methods with a * "factory-bean" reference) for the type check. Note that FactoryBeans need to be * eagerly initialized to determine their type: So be aware that passing in "true" * for this flag will initialize FactoryBeans and "factory-bean" references. * @return a Map with the matching beans, containing the bean names as * keys and the corresponding bean instances as values * @throws BeansException if a bean could not be created * @see FactoryBean#getObjectType * @see BeanFactoryUtils#beansOfTypeIncludingAncestors(ListableBeanFactory, Class, boolean, boolean) */
  48.     <T> Map<String, T> getBeansOfType(Class<T> type, boolean includeNonSingletons, boolean allowEagerInit)
  49.             throws BeansException;
  51.     //-------------------------------------------------------------------------
  52.     // 查找使用注解的类
  53.     //-------------------------------------------------------------------------
  55.     /** * Find all names of beans whose {@code Class} has the supplied {@link Annotation} * type, without creating any bean instances yet. * @param annotationType the type of annotation to look for * @return the names of all matching beans * @since 4.0 */
  56.     String[] getBeanNamesForAnnotation(Class<? extends Annotation> annotationType);
  58.     /** * Find all beans whose {@code Class} has the supplied {@link Annotation} type, * returning a Map of bean names with corresponding bean instances. * @param annotationType the type of annotation to look for * @return a Map with the matching beans, containing the bean names as * keys and the corresponding bean instances as values * @throws BeansException if a bean could not be created * @since 3.0 */
  59.      // 根据注解类型，查找所有有这个注解的Bean名和Bean的Map
  60.     Map<String, Object> getBeansWithAnnotation(Class<? extends Annotation> annotationType) throws BeansException;
  62.     //-------------------------------------------------------------------------
  63.     // 查找一个类上的注解,如果找不到,父类,接口使用注解也算.
  64.     //-------------------------------------------------------------------------
  66.     /** * Find an {@link Annotation} of {@code annotationType} on the specified * bean, traversing its interfaces and super classes if no annotation can be * found on the given class itself. * @param beanName the name of the bean to look for annotations on * @param annotationType the annotation class to look for * @return the annotation of the given type if found, or {@code null} * @throws NoSuchBeanDefinitionException if there is no bean with the given name * @since 3.0 */
  67.      // 根据指定Bean名和注解类型查找指定的Bean
  68.     <A extends Annotation> A findAnnotationOnBean(String beanName, Class<A> annotationType)
  69.             throws NoSuchBeanDefinitionException;
  71. }

发表评论

表情：
评论列表 （有 0 条评论，25人围观）

还没有评论，来说两句吧...

相关阅读

    相关 接口

    接口的基本概念 --------------------  Java接口是一系列方法的声明，是一些方法特征的集合。一个接口只有方法的特征没有方法的实现，因此这些方法可以

    小灰灰小灰灰/ 0 赞/ 935 阅读