类 ServiceLocatorFactoryBean
- java.lang.Object
- org.springframework.beans.factory.config.ServiceLocatorFactoryBean
- 所有已实现的接口:
Aware
,BeanFactoryAware
,FactoryBean<Object>
,InitializingBean
public class ServiceLocatorFactoryBean extends Object implements FactoryBean<Object>, BeanFactoryAware, InitializingBean
AFactoryBean
implementation that takes an interface which must have one or more methods with the signaturesMyType xxx()
orMyType xxx(MyIdType id)
(typically,MyService getService()
orMyService getService(String id)
) and creates a dynamic proxy which implements that interface, delegating to an underlyingBeanFactory
.Such service locators permit the decoupling of calling code from the
BeanFactory
API, by using an appropriate custom locator interface. They will typically be used for prototype beans, i.e. for factory methods that are supposed to return a new instance for each call. The client receives a reference to the service locator via setter or constructor injection, to be able to invoke the locator's factory methods on demand. For singleton beans, direct setter or constructor injection of the target bean is preferable.On invocation of the no-arg factory method, or the single-arg factory method with a String id of
null
or empty String, if exactly one bean in the factory matches the return type of the factory method, that bean is returned, otherwise aNoSuchBeanDefinitionException
is thrown.On invocation of the single-arg factory method with a non-null (and non-empty) argument, the proxy returns the result of a
BeanFactory.getBean(String)
call, using a stringified version of the passed-in id as bean name.A factory method argument will usually be a String, but can also be an int or a custom enumeration type, for example, stringified via
toString
. The resulting String can be used as bean name as-is, provided that corresponding beans are defined in the bean factory. Alternatively, a custom mapping between service IDs and bean names can be defined.By way of an example, consider the following service locator interface. Note that this interface is not dependent on any Spring APIs.
package a.b.c; public interface ServiceFactory { public MyService getService(); }
A sample config in an XML-based
BeanFactory
might look as follows:<beans> <!-- Prototype bean since we have state --> <bean id="myService" class="a.b.c.MyService" singleton="false"/> <!-- will lookup the above 'myService' bean by *TYPE* --> <bean id="myServiceFactory" class="org.springframework.beans.factory.config.ServiceLocatorFactoryBean"> <property name="serviceLocatorInterface" value="a.b.c.ServiceFactory"/> </bean> <bean id="clientBean" class="a.b.c.MyClientBean"> <property name="myServiceFactory" ref="myServiceFactory"/> </bean> </beans>
The attendant
MyClientBean
class implementation might then look something like this:package a.b.c; public class MyClientBean { private ServiceFactory myServiceFactory; // actual implementation provided by the Spring container public void setServiceFactory(ServiceFactory myServiceFactory) { this.myServiceFactory = myServiceFactory; } public void someBusinessMethod() { // get a 'fresh', brand new MyService instance MyService service = this.myServiceFactory.getService(); // use the service object to effect the business logic... } }
By way of an example that looks up a bean by name, consider the following service locator interface. Again, note that this interface is not dependent on any Spring APIs.
package a.b.c; public interface ServiceFactory { public MyService getService (String serviceName); }
A sample config in an XML-based
BeanFactory
might look as follows:<beans> <!-- Prototype beans since we have state (both extend MyService) --> <bean id="specialService" class="a.b.c.SpecialService" singleton="false"/> <bean id="anotherService" class="a.b.c.AnotherService" singleton="false"/> <bean id="myServiceFactory" class="org.springframework.beans.factory.config.ServiceLocatorFactoryBean"> <property name="serviceLocatorInterface" value="a.b.c.ServiceFactory"/> </bean> <bean id="clientBean" class="a.b.c.MyClientBean"> <property name="myServiceFactory" ref="myServiceFactory"/> </bean> </beans>
The attendant
MyClientBean
class implementation might then look something like this:package a.b.c; public class MyClientBean { private ServiceFactory myServiceFactory; // actual implementation provided by the Spring container public void setServiceFactory(ServiceFactory myServiceFactory) { this.myServiceFactory = myServiceFactory; } public void someBusinessMethod() { // get a 'fresh', brand new MyService instance MyService service = this.myServiceFactory.getService("specialService"); // use the service object to effect the business logic... } public void anotherBusinessMethod() { // get a 'fresh', brand new MyService instance MyService service = this.myServiceFactory.getService("anotherService"); // use the service object to effect the business logic... } }
See
ObjectFactoryCreatingFactoryBean
for an alternate approach.- 从以下版本开始:
- 1.1.4
- 作者:
- Colin Sampaleanu, Juergen Hoeller
- 另请参阅:
setServiceLocatorInterface(java.lang.Class<?>)
,setServiceMappings(java.util.Properties)
,ObjectFactoryCreatingFactoryBean
构造器概要
构造器 构造器 说明 ServiceLocatorFactoryBean()
方法概要
所有方法 实例方法 具体方法 修饰符和类型 方法 说明 void
afterPropertiesSet()
Invoked by the containingBeanFactory
after it has set all bean properties and satisfiedBeanFactoryAware
,ApplicationContextAware
etc.protected Exception
createServiceLocatorException(Constructor<Exception> exceptionConstructor, BeansException cause)
Create a service locator exception for the given cause.protected Constructor<Exception>
determineServiceLocatorExceptionConstructor(Class<? extends Exception> exceptionClass)
Determine the constructor to use for the given service locator exception class.Object
getObject()
Return an instance (possibly shared or independent) of the object managed by this factory.Class<?>
getObjectType()
Return the type of object that this FactoryBean creates, ornull
if not known in advance.boolean
isSingleton()
Is the object managed by this factory a singleton?void
setBeanFactory(BeanFactory beanFactory)
Callback that supplies the owning factory to a bean instance.void
setServiceLocatorExceptionClass(Class<? extends Exception> serviceLocatorExceptionClass)
Set the exception class that the service locator should throw if service lookup failed.void
setServiceLocatorInterface(Class<?> interfaceType)
Set the service locator interface to use, which must have one or more methods with the signaturesMyType xxx()
orMyType xxx(MyIdType id)
(typically,MyService getService()
orMyService getService(String id)
).void
setServiceMappings(Properties serviceMappings)
Set mappings between service ids (passed into the service locator) and bean names (in the bean factory).
构造器详细资料
ServiceLocatorFactoryBean
public ServiceLocatorFactoryBean()
方法详细资料
setServiceLocatorInterface
public void setServiceLocatorInterface(Class<?> interfaceType)
Set the service locator interface to use, which must have one or more methods with the signaturesMyType xxx()
orMyType xxx(MyIdType id)
(typically,MyService getService()
orMyService getService(String id)
). See theclass-level Javadoc
for information on the semantics of such methods.
setServiceLocatorExceptionClass
public void setServiceLocatorExceptionClass(Class<? extends Exception> serviceLocatorExceptionClass)
Set the exception class that the service locator should throw if service lookup failed. The specified exception class must have a constructor with one of the following parameter types:(String, Throwable)
or(Throwable)
or(String)
.If not specified, subclasses of Spring's BeansException will be thrown, for example NoSuchBeanDefinitionException. As those are unchecked, the caller does not need to handle them, so it might be acceptable that Spring exceptions get thrown as long as they are just handled generically.
setServiceMappings
public void setServiceMappings(Properties serviceMappings)
Set mappings between service ids (passed into the service locator) and bean names (in the bean factory). Service ids that are not defined here will be treated as bean names as-is.The empty string as service id key defines the mapping for
null
and empty string, and for factory methods without parameter. If not defined, a single matching bean will be retrieved from the bean factory.- 参数:
serviceMappings
- mappings between service ids and bean names, with service ids as keys as bean names as values
setBeanFactory
public void setBeanFactory(BeanFactory beanFactory) throws BeansException
从接口复制的说明:BeanFactoryAware
Callback that supplies the owning factory to a bean instance.Invoked after the population of normal bean properties but before an initialization callback such as
InitializingBean.afterPropertiesSet()
or a custom init-method.- 指定者:
setBeanFactory
在接口中BeanFactoryAware
- 参数:
beanFactory
- owning BeanFactory (nevernull
). The bean can immediately call methods on the factory.- 抛出:
BeansException
- in case of initialization errors- 另请参阅:
BeanInitializationException
afterPropertiesSet
public void afterPropertiesSet()
从接口复制的说明:InitializingBean
Invoked by the containingBeanFactory
after it has set all bean properties and satisfiedBeanFactoryAware
,ApplicationContextAware
etc.This method allows the bean instance to perform validation of its overall configuration and final initialization when all bean properties have been set.
- 指定者:
afterPropertiesSet
在接口中InitializingBean
determineServiceLocatorExceptionConstructor
protected Constructor<Exception> determineServiceLocatorExceptionConstructor(Class<? extends Exception> exceptionClass)
Determine the constructor to use for the given service locator exception class. Only called in case of a custom service locator exception.The default implementation looks for a constructor with one of the following parameter types:
(String, Throwable)
or(Throwable)
or(String)
.- 参数:
exceptionClass
- the exception class- 返回:
- the constructor to use
- 另请参阅:
setServiceLocatorExceptionClass(java.lang.Class<? extends java.lang.Exception>)
createServiceLocatorException
protected Exception createServiceLocatorException(Constructor<Exception> exceptionConstructor, BeansException cause)
Create a service locator exception for the given cause. Only called in case of a custom service locator exception.The default implementation can handle all variations of message and exception arguments.
- 参数:
exceptionConstructor
- the constructor to usecause
- the cause of the service lookup failure- 返回:
- the service locator exception to throw
- 另请参阅:
setServiceLocatorExceptionClass(java.lang.Class<? extends java.lang.Exception>)
getObject
public Object getObject()
从接口复制的说明:FactoryBean
Return an instance (possibly shared or independent) of the object managed by this factory.As with a
BeanFactory
, this allows support for both the Singleton and Prototype design pattern.If this FactoryBean is not fully initialized yet at the time of the call (for example because it is involved in a circular reference), throw a corresponding
FactoryBeanNotInitializedException
.As of Spring 2.0, FactoryBeans are allowed to return
null
objects. The factory will consider this as normal value to be used; it will not throw a FactoryBeanNotInitializedException in this case anymore. FactoryBean implementations are encouraged to throw FactoryBeanNotInitializedException themselves now, as appropriate.- 指定者:
getObject
在接口中FactoryBean<Object>
- 返回:
- an instance of the bean (can be
null
) - 另请参阅:
FactoryBeanNotInitializedException
getObjectType
public Class<?> getObjectType()
从接口复制的说明:FactoryBean
Return the type of object that this FactoryBean creates, ornull
if not known in advance.This allows one to check for specific types of beans without instantiating objects, for example on autowiring.
In the case of implementations that are creating a singleton object, this method should try to avoid singleton creation as far as possible; it should rather estimate the type in advance. For prototypes, returning a meaningful type here is advisable too.
This method can be called before this FactoryBean has been fully initialized. It must not rely on state created during initialization; of course, it can still use such state if available.
NOTE: Autowiring will simply ignore FactoryBeans that return
null
here. Therefore it is highly recommended to implement this method properly, using the current state of the FactoryBean.- 指定者:
getObjectType
在接口中FactoryBean<Object>
- 返回:
- the type of object that this FactoryBean creates, or
null
if not known at the time of the call - 另请参阅:
ListableBeanFactory.getBeansOfType(java.lang.Class<T>)
isSingleton
public boolean isSingleton()
从接口复制的说明:FactoryBean
Is the object managed by this factory a singleton? That is, willFactoryBean.getObject()
always return the same object (a reference that can be cached)?NOTE: If a FactoryBean indicates to hold a singleton object, the object returned from
getObject()
might get cached by the owning BeanFactory. Hence, do not returntrue
unless the FactoryBean always exposes the same reference.The singleton status of the FactoryBean itself will generally be provided by the owning BeanFactory; usually, it has to be defined as singleton there.
NOTE: This method returning
false
does not necessarily indicate that returned objects are independent instances. An implementation of the extendedSmartFactoryBean
interface may explicitly indicate independent instances through itsSmartFactoryBean.isPrototype()
method. PlainFactoryBean
implementations which do not implement this extended interface are simply assumed to always return independent instances if theisSingleton()
implementation returnsfalse
.- 指定者:
isSingleton
在接口中FactoryBean<Object>
- 返回:
- whether the exposed object is a singleton
- 另请参阅:
FactoryBean.getObject()
,SmartFactoryBean.isPrototype()