BeanDefinition接口
BeanDefinition 描述一个 Bean 实例，这个实例有哪些属性值、构造函数以及一些其他信息，就是描述Bean实例的信息。
BeanDefinition是一个接口，允许BeanFactoryPostProcessor 内省和修改属性值和其他 Bean 元数据。
点击了解BeanFactoryPostProcessor
意义
在spring流程中是现有BeanDefinition再有bean，bean是根据BeanDefinition中的信息去创建的，当然在还没创建bean的时候还可以修改BeanDefinition中的信息，这个就是BeanFactoryPostProcessor 接口的主要功能，如我们在xml中定义的${jdbc.name}最终替换为真正的值就是在实现BeanFactoryPostProcessor 接口完成的。
源码
package org.springframework.beans.factory.config;import org.springframework.beans.BeanMetadataElement;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.core.AttributeAccessor;
import org.springframework.core.ResolvableType;
import org.springframework.lang.Nullable;/*** A BeanDefinition describes a bean instance, which has property values,* constructor argument values, and further information supplied by* concrete implementations.** <p>This is just a minimal interface: The main intention is to allow a* {@link BeanFactoryPostProcessor} to introspect and modify property values* and other bean metadata.** @author Juergen Hoeller* @author Rob Harrop* @since 19.03.2004* @see ConfigurableListableBeanFactory#getBeanDefinition* @see org.springframework.beans.factory.support.RootBeanDefinition* @see org.springframework.beans.factory.support.ChildBeanDefinition*/
public interface BeanDefinition extends AttributeAccessor, BeanMetadataElement {/*** Scope identifier for the standard singleton scope: {@value}.* <p>Note that extended bean factories might support further scopes.* @see #setScope* @see ConfigurableBeanFactory#SCOPE_SINGLETON*/String SCOPE_SINGLETON = ConfigurableBeanFactory.SCOPE_SINGLETON;/*** Scope identifier for the standard prototype scope: {@value}.* <p>Note that extended bean factories might support further scopes.* @see #setScope* @see ConfigurableBeanFactory#SCOPE_PROTOTYPE*/String SCOPE_PROTOTYPE = ConfigurableBeanFactory.SCOPE_PROTOTYPE;/*** Role hint indicating that a {@code BeanDefinition} is a major part* of the application. Typically corresponds to a user-defined bean.*/int ROLE_APPLICATION = 0;/*** Role hint indicating that a {@code BeanDefinition} is a supporting* part of some larger configuration, typically an outer* {@link org.springframework.beans.factory.parsing.ComponentDefinition}.* {@code SUPPORT} beans are considered important enough to be aware* of when looking more closely at a particular* {@link org.springframework.beans.factory.parsing.ComponentDefinition},* but not when looking at the overall configuration of an application.*/int ROLE_SUPPORT = 1;/*** Role hint indicating that a {@code BeanDefinition} is providing an* entirely background role and has no relevance to the end-user. This hint is* used when registering beans that are completely part of the internal workings* of a {@link org.springframework.beans.factory.parsing.ComponentDefinition}.*/int ROLE_INFRASTRUCTURE = 2;// Modifiable attributes/*** Set the name of the parent definition of this bean definition, if any.*/void setParentName(@Nullable String parentName);/*** Return the name of the parent definition of this bean definition, if any.*/@NullableString getParentName();/*** Specify the bean class name of this bean definition.* <p>The class name can be modified during bean factory post-processing,* typically replacing the original class name with a parsed variant of it.* @see #setParentName* @see #setFactoryBeanName* @see #setFactoryMethodName*/void setBeanClassName(@Nullable String beanClassName);/*** Return the current bean class name of this bean definition.* <p>Note that this does not have to be the actual class name used at runtime, in* case of a child definition overriding/inheriting the class name from its parent.* Also, this may just be the class that a factory method is called on, or it may* even be empty in case of a factory bean reference that a method is called on.* Hence, do <i>not</i> consider this to be the definitive bean type at runtime but* rather only use it for parsing purposes at the individual bean definition level.* @see #getParentName()* @see #getFactoryBeanName()* @see #getFactoryMethodName()*/@NullableString getBeanClassName();/*** Override the target scope of this bean, specifying a new scope name.* @see #SCOPE_SINGLETON* @see #SCOPE_PROTOTYPE*/void setScope(@Nullable String scope);/*** Return the name of the current target scope for this bean,* or {@code null} if not known yet.*/@NullableString getScope();/*** Set whether this bean should be lazily initialized.* <p>If {@code false}, the bean will get instantiated on startup by bean* factories that perform eager initialization of singletons.*/void setLazyInit(boolean lazyInit);/*** Return whether this bean should be lazily initialized, i.e. not* eagerly instantiated on startup. Only applicable to a singleton bean.*/boolean isLazyInit();/*** Set the names of the beans that this bean depends on being initialized.* The bean factory will guarantee that these beans get initialized first.* <p>Note that dependencies are normally expressed through bean properties or* constructor arguments. This property should just be necessary for other kinds* of dependencies like statics (*ugh*) or database preparation on startup.*/void setDependsOn(@Nullable String... dependsOn);/*** Return the bean names that this bean depends on.*/@NullableString[] getDependsOn();/*** Set whether this bean is a candidate for getting autowired into some other bean.* <p>Note that this flag is designed to only affect type-based autowiring.* It does not affect explicit references by name, which will get resolved even* if the specified bean is not marked as an autowire candidate. As a consequence,* autowiring by name will nevertheless inject a bean if the name matches.*/void setAutowireCandidate(boolean autowireCandidate);/*** Return whether this bean is a candidate for getting autowired into some other bean.*/boolean isAutowireCandidate();/*** Set whether this bean is a primary autowire candidate.* <p>If this value is {@code true} for exactly one bean among multiple* matching candidates, it will serve as a tie-breaker.* @see #setFallback*/void setPrimary(boolean primary);/*** Return whether this bean is a primary autowire candidate.*/boolean isPrimary();/*** Set whether this bean is a fallback autowire candidate.* <p>If this value is {@code true} for all beans but one among multiple* matching candidates, the remaining bean will be selected.* @since 6.2* @see #setPrimary*/void setFallback(boolean fallback);/*** Return whether this bean is a fallback autowire candidate.* @since 6.2*/boolean isFallback();/*** Specify the factory bean to use, if any.* This is the name of the bean to call the specified factory method on.* <p>A factory bean name is only necessary for instance-based factory methods.* For static factory methods, the method will be derived from the bean class.* @see #setFactoryMethodName* @see #setBeanClassName*/void setFactoryBeanName(@Nullable String factoryBeanName);/*** Return the factory bean name, if any.* <p>This will be {@code null} for static factory methods which will* be derived from the bean class instead.* @see #getFactoryMethodName()* @see #getBeanClassName()*/@NullableString getFactoryBeanName();/*** Specify a factory method, if any. This method will be invoked with* constructor arguments, or with no arguments if none are specified.* The method will be invoked on the specified factory bean, if any,* or otherwise as a static method on the local bean class.* @see #setFactoryBeanName* @see #setBeanClassName*/void setFactoryMethodName(@Nullable String factoryMethodName);/*** Return a factory method, if any.* @see #getFactoryBeanName()* @see #getBeanClassName()*/@NullableString getFactoryMethodName();/*** Return the constructor argument values for this bean.* <p>The returned instance can be modified during bean factory post-processing.* @return the ConstructorArgumentValues object (never {@code null})*/ConstructorArgumentValues getConstructorArgumentValues();/*** Return if there are constructor argument values defined for this bean.* @since 5.0.2* @see #getConstructorArgumentValues()*/default boolean hasConstructorArgumentValues() {return !getConstructorArgumentValues().isEmpty();}/*** Return the property values to be applied to a new instance of the bean.* <p>The returned instance can be modified during bean factory post-processing.* @return the MutablePropertyValues object (never {@code null})*/MutablePropertyValues getPropertyValues();/*** Return if there are property values defined for this bean.* @since 5.0.2* @see #getPropertyValues()*/default boolean hasPropertyValues() {return !getPropertyValues().isEmpty();}/*** Set the name of the initializer method.* @since 5.1*/void setInitMethodName(@Nullable String initMethodName);/*** Return the name of the initializer method.* @since 5.1*/@NullableString getInitMethodName();/*** Set the name of the destroy method.* @since 5.1*/void setDestroyMethodName(@Nullable String destroyMethodName);/*** Return the name of the destroy method.* @since 5.1*/@NullableString getDestroyMethodName();/*** Set the role hint for this {@code BeanDefinition}. The role hint* provides the frameworks as well as tools an indication of* the role and importance of a particular {@code BeanDefinition}.* @since 5.1* @see #ROLE_APPLICATION* @see #ROLE_SUPPORT* @see #ROLE_INFRASTRUCTURE*/void setRole(int role);/*** Get the role hint for this {@code BeanDefinition}. The role hint* provides the frameworks as well as tools an indication of* the role and importance of a particular {@code BeanDefinition}.* @see #ROLE_APPLICATION* @see #ROLE_SUPPORT* @see #ROLE_INFRASTRUCTURE*/int getRole();/*** Set a human-readable description of this bean definition.* @since 5.1*/void setDescription(@Nullable String description);/*** Return a human-readable description of this bean definition.*/@NullableString getDescription();// Read-only attributes/*** Return a resolvable type for this bean definition,* based on the bean class or other specific metadata.* <p>This is typically fully resolved on a runtime-merged bean definition* but not necessarily on a configuration-time definition instance.* @return the resolvable type (potentially {@link ResolvableType#NONE})* @since 5.2* @see ConfigurableBeanFactory#getMergedBeanDefinition*/ResolvableType getResolvableType();/*** Return whether this a <b>Singleton</b>, with a single, shared instance* returned on all calls.* @see #SCOPE_SINGLETON*/boolean isSingleton();/*** Return whether this a <b>Prototype</b>, with an independent instance* returned for each call.* @since 3.0* @see #SCOPE_PROTOTYPE*/boolean isPrototype();/*** Return whether this bean is "abstract", that is, not meant to be instantiated* itself but rather just serving as parent for concrete child bean definitions.*/boolean isAbstract();/*** Return a description of the resource that this bean definition* came from (for the purpose of showing context in case of errors).*/@NullableString getResourceDescription();/*** Return the originating BeanDefinition, or {@code null} if none.* <p>Allows for retrieving the decorated bean definition, if any.* <p>Note that this method returns the immediate originator. Iterate through the* originator chain to find the original BeanDefinition as defined by the user.*/@NullableBeanDefinition getOriginatingBeanDefinition();}| 方法签名 | 中文解释 |
|---|---|
| void setParentName(@Nullable String parentName) | 设置该 bean 定义的父定义的名称（如果有）。 |
| @Nullable String getParentName() | 返回该 bean 定义的父定义的名称（如果有）。 |
| void setBeanClassName(@Nullable String beanClassName) | 指定该 bean 定义的 bean 类名称。 |
| @Nullable String getBeanClassName() | 返回该 bean 定义的当前 bean 类名称。 |
| void setScope(@Nullable String scope) | 重写该 bean 的目标范围，指定新的范围名称。 |
| @Nullable String getScope() | 返回该 bean 当前目标范围的名称，或如果尚不清楚则返回 null。 |
| void setLazyInit(boolean lazyInit) | 设置该 bean 是否应延迟初始化。 |
| boolean isLazyInit() | 返回该 bean 是否应延迟初始化，即不在启动时急切实例化。仅适用于单例 bean。 |
| void setDependsOn(@Nullable String… dependsOn) | 设置该 bean 依赖于初始化的 bean 的名称。 |
| @Nullable String[] getDependsOn() | 返回该 bean 依赖的 bean 名称。 |
| void setAutowireCandidate(boolean autowireCandidate) | 设置该 bean 是否是某些其他 bean 自动装配的候选者。 |
| boolean isAutowireCandidate() | 返回该 bean 是否是某些其他 bean 自动装配的候选者。 |
| void setPrimary(boolean primary) | 设置该 bean 是否是主要自动装配候选者。 |
| boolean isPrimary() | 返回该 bean 是否是主要自动装配候选者。 |
| void setFallback(boolean fallback) | 设置该 bean 是否是后备自动装配候选者。 |
| boolean isFallback() | 返回该 bean 是否是后备自动装配候选者。 |
| void setFactoryBeanName(@Nullable String factoryBeanName) | 指定要使用的工厂 bean（如果有）。这是调用指定工厂方法的 bean 的名称。 |
| @Nullable String getFactoryBeanName() | 返回工厂 bean 名称（如果有）。 |
| void setFactoryMethodName(@Nullable String factoryMethodName) | 指定工厂方法（如果有）。此方法将使用构造函数参数调用，或者如果没有指定参数则不带参数调用。 |
| @Nullable String getFactoryMethodName() | 返回工厂方法（如果有）。 |
| ConstructorArgumentValues getConstructorArgumentValues() | 返回该 bean 的构造函数参数值。返回的实例可以在 bean 工厂后处理期间进行修改。 |
| boolean hasConstructorArgumentValues() | 返回是否定义了该 bean 的构造函数参数值。 |
| MutablePropertyValues getPropertyValues() | 返回应用于该 bean 的新实例的属性值。返回的实例可以在 bean 工厂后处理期间进行修改。 |
| boolean hasPropertyValues() | 返回是否为该 bean 定义了属性值。 |
| void setInitMethodName(@Nullable String initMethodName) | 设置初始化方法的名称。 |
| @Nullable String getInitMethodName() | 返回初始化方法的名称。 |
| void setDestroyMethodName(@Nullable String destroyMethodName) | 设置销毁方法的名称。 |
| @Nullable String getDestroyMethodName() | 返回销毁方法的名称。 |
| void setRole(int role) | 设置该 BeanDefinition 的角色提示。 |
| int getRole() | 获取该 BeanDefinition 的角色提示。 |
| void setDescription(@Nullable String description) | 设置该 bean 定义的人类可读描述。 |
| @Nullable String getDescription() | 返回该 bean 定义的人类可读描述。 |
| ResolvableType getResolvableType() | 返回基于 bean 类或其他特定元数据的可解析类型。 |
| boolean isSingleton() | 返回此 bean 是否为单例，所有调用都返回单个共享实例。 |
| boolean isPrototype() | 返回此 bean 是否为原型，每次调用返回一个独立的实例。 |
| boolean isAbstract() | 返回此 bean 是否为抽象，即不是用于实例化自身，而是作为具体子 bean 定义的父类。 |
| @Nullable String getResourceDescription() | 返回该 bean 定义的资源描述（用于在出现错误时显示上下文）。 |
| @Nullable BeanDefinition getOriginatingBeanDefinition() | 返回原始的 BeanDefinition，如果没有则返回 null。 |
