Spring源碼解析--IOC根容器Beanfactory詳解

BeanFactory和FactoryBean的聯繫和區別

BeanFactory是整個Spring容器的根容器，裏面描述了在全部的子類或子接口當中對容器的處理原則和職責，包括生命週期的一些約定。

FactoryBean自己存活在BeanFactory當中，也是一種工廠。這個工廠的做用是用於獲取FactoryBean所建立的對象。在建立的對象的時候，對象中的某些方法的前面和後面額外執行一些操做，實現AOP。

 

BeanFactory接口所在的位置：

 BeanFactory源碼

  1 /*
  2  * Copyright 2002-2011 the original author or authors.
  3  *
  4  * Licensed under the Apache License, Version 2.0 (the "License");
  5  * you may not use this file except in compliance with the License.
  6  * You may obtain a copy of the License at
  7  *
  8  *      http://www.apache.org/licenses/LICENSE-2.0
  9  *
 10  * Unless required by applicable law or agreed to in writing, software
 11  * distributed under the License is distributed on an "AS IS" BASIS,
 12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 13  * See the License for the specific language governing permissions and
 14  * limitations under the License.
 15  */
 16 
 17 package org.springframework.beans.factory;
 18 
 19 import org.springframework.beans.BeansException;
 20 
 21 /**
 22  * The root interface for accessing a Spring bean container.
 23  * This is the basic client view of a bean container;
 24  * further interfaces such as {@link ListableBeanFactory} and
 25  * {@link org.springframework.beans.factory.config.ConfigurableBeanFactory}
 26  * are available for specific purposes.
 27  *
 28  * <p>This interface is implemented by objects that hold a number of bean definitions,
 29  * each uniquely identified by a String name. Depending on the bean definition,
 30  * the factory will return either an independent instance of a contained object
 31  * (the Prototype design pattern), or a single shared instance (a superior
 32  * alternative to the Singleton design pattern, in which the instance is a
 33  * singleton in the scope of the factory). Which type of instance will be returned
 34  * depends on the bean factory configuration: the API is the same. Since Spring
 35  * 2.0, further scopes are available depending on the concrete application
 36  * context (e.g. "request" and "session" scopes in a web environment).
 37  *
 38  * <p>The point of this approach is that the BeanFactory is a central registry
 39  * of application components, and centralizes configuration of application
 40  * components (no more do individual objects need to read properties files,
 41  * for example). See chapters 4 and 11 of "Expert One-on-One J2EE Design and
 42  * Development" for a discussion of the benefits of this approach.
 43  *
 44  * <p>Note that it is generally better to rely on Dependency Injection
 45  * ("push" configuration) to configure application objects through setters
 46  * or constructors, rather than use any form of "pull" configuration like a
 47  * BeanFactory lookup. Spring's Dependency Injection functionality is
 48  * implemented using this BeanFactory interface and its subinterfaces.
 49  *
 50  * <p>Normally a BeanFactory will load bean definitions stored in a configuration
 51  * source (such as an XML document), and use the <code>org.springframework.beans</code>
 52  * package to configure the beans. However, an implementation could simply return
 53  * Java objects it creates as necessary directly in Java code. There are no
 54  * constraints on how the definitions could be stored: LDAP, RDBMS, XML,
 55  * properties file, etc. Implementations are encouraged to support references
 56  * amongst beans (Dependency Injection).
 57  *
 58  * <p>In contrast to the methods in {@link ListableBeanFactory}, all of the
 59  * operations in this interface will also check parent factories if this is a
 60  * {@link HierarchicalBeanFactory}. If a bean is not found in this factory instance,
 61  * the immediate parent factory will be asked. Beans in this factory instance
 62  * are supposed to override beans of the same name in any parent factory.
 63  *
 64  * <p>Bean factory implementations should support the standard bean lifecycle interfaces
 65  * as far as possible. The full set of initialization methods and their standard order is:<br>
 66  * 1. BeanNameAware's <code>setBeanName</code><br>
 67  * 2. BeanClassLoaderAware's <code>setBeanClassLoader</code><br>
 68  * 3. BeanFactoryAware's <code>setBeanFactory</code><br>
 69  * 4. ResourceLoaderAware's <code>setResourceLoader</code>
 70  * (only applicable when running in an application context)<br>
 71  * 5. ApplicationEventPublisherAware's <code>setApplicationEventPublisher</code>
 72  * (only applicable when running in an application context)<br>
 73  * 6. MessageSourceAware's <code>setMessageSource</code>
 74  * (only applicable when running in an application context)<br>
 75  * 7. ApplicationContextAware's <code>setApplicationContext</code>
 76  * (only applicable when running in an application context)<br>
 77  * 8. ServletContextAware's <code>setServletContext</code>
 78  * (only applicable when running in a web application context)<br>
 79  * 9. <code>postProcessBeforeInitialization</code> methods of BeanPostProcessors<br>
 80  * 10. InitializingBean's <code>afterPropertiesSet</code><br>
 81  * 11. a custom init-method definition<br>
 82  * 12. <code>postProcessAfterInitialization</code> methods of BeanPostProcessors
 83  *
 84  * <p>On shutdown of a bean factory, the following lifecycle methods apply:<br>
 85  * 1. DisposableBean's <code>destroy</code><br>
 86  * 2. a custom destroy-method definition
 87  *
 88  * @author Rod Johnson
 89  * @author Juergen Hoeller
 90  * @author Chris Beams
 91  * @since 13 April 2001
 92  * @see BeanNameAware#setBeanName
 93  * @see BeanClassLoaderAware#setBeanClassLoader
 94  * @see BeanFactoryAware#setBeanFactory
 95  * @see org.springframework.context.ResourceLoaderAware#setResourceLoader
 96  * @see org.springframework.context.ApplicationEventPublisherAware#setApplicationEventPublisher
 97  * @see org.springframework.context.MessageSourceAware#setMessageSource
 98  * @see org.springframework.context.ApplicationContextAware#setApplicationContext
 99  * @see org.springframework.web.context.ServletContextAware#setServletContext
100  * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessBeforeInitialization
101  * @see InitializingBean#afterPropertiesSet
102  * @see org.springframework.beans.factory.support.RootBeanDefinition#getInitMethodName
103  * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessAfterInitialization
104  * @see DisposableBean#destroy
105  * @see org.springframework.beans.factory.support.RootBeanDefinition#getDestroyMethodName
106  */
107 public interface BeanFactory {
108 
109     /**
110      * Used to dereference a {@link FactoryBean} instance and distinguish it from
111      * beans <i>created</i> by the FactoryBean. For example, if the bean named
112      * <code>myJndiObject</code> is a FactoryBean, getting <code>&myJndiObject</code>
113      * will return the factory, not the instance returned by the factory.
114      */
115     String FACTORY_BEAN_PREFIX = "&";
116 
117     /**
118      * Return an instance, which may be shared or independent, of the specified bean.
119      * <p>This method allows a Spring BeanFactory to be used as a replacement for the
120      * Singleton or Prototype design pattern. Callers may retain references to
121      * returned objects in the case of Singleton beans.
122      * <p>Translates aliases back to the corresponding canonical bean name.
123      * Will ask the parent factory if the bean cannot be found in this factory instance.
124      * @param name the name of the bean to retrieve
125      * @return an instance of the bean
126      * @throws NoSuchBeanDefinitionException if there is no bean definition
127      * with the specified name
128      * @throws BeansException if the bean could not be obtained
129      */
130     Object getBean(String name) throws BeansException;
131 
132     /**
133      * Return an instance, which may be shared or independent, of the specified bean.
134      * <p>Behaves the same as {@link #getBean(String)}, but provides a measure of type
135      * safety by throwing a BeanNotOfRequiredTypeException if the bean is not of the
136      * required type. This means that ClassCastException can't be thrown on casting
137      * the result correctly, as can happen with {@link #getBean(String)}.
138      * <p>Translates aliases back to the corresponding canonical bean name.
139      * Will ask the parent factory if the bean cannot be found in this factory instance.
140      * @param name the name of the bean to retrieve
141      * @param requiredType type the bean must match. Can be an interface or superclass
142      * of the actual class, or <code>null</code> for any match. For example, if the value
143      * is <code>Object.class</code>, this method will succeed whatever the class of the
144      * returned instance.
145      * @return an instance of the bean
146      * @throws NoSuchBeanDefinitionException if there's no such bean definition
147      * @throws BeanNotOfRequiredTypeException if the bean is not of the required type
148      * @throws BeansException if the bean could not be created
149      */
150     <T> T getBean(String name, Class<T> requiredType) throws BeansException;
151 
152     /**
153      * Return the bean instance that uniquely matches the given object type, if any.
154      * @param requiredType type the bean must match; can be an interface or superclass.
155      * {@code null} is disallowed.
156      * <p>This method goes into {@link ListableBeanFactory} by-type lookup territory
157      * but may also be translated into a conventional by-name lookup based on the name
158      * of the given type. For more extensive retrieval operations across sets of beans,
159      * use {@link ListableBeanFactory} and/or {@link BeanFactoryUtils}.
160      * @return an instance of the single bean matching the required type
161      * @throws NoSuchBeanDefinitionException if there is not exactly one matching bean found
162      * @since 3.0
163      * @see ListableBeanFactory
164      */
165     <T> T getBean(Class<T> requiredType) throws BeansException;
166 
167     /**
168      * Return an instance, which may be shared or independent, of the specified bean.
169      * <p>Allows for specifying explicit constructor arguments / factory method arguments,
170      * overriding the specified default arguments (if any) in the bean definition.
171      * @param name the name of the bean to retrieve
172      * @param args arguments to use if creating a prototype using explicit arguments to a
173      * static factory method. It is invalid to use a non-null args value in any other case.
174      * @return an instance of the bean
175      * @throws NoSuchBeanDefinitionException if there's no such bean definition
176      * @throws BeanDefinitionStoreException if arguments have been given but
177      * the affected bean isn't a prototype
178      * @throws BeansException if the bean could not be created
179      * @since 2.5
180      */
181     Object getBean(String name, Object... args) throws BeansException;
182 
183     /**
184      * Does this bean factory contain a bean definition or externally registered singleton
185      * instance with the given name?
186      * <p>If the given name is an alias, it will be translated back to the corresponding
187      * canonical bean name.
188      * <p>If this factory is hierarchical, will ask any parent factory if the bean cannot
189      * be found in this factory instance.
190      * <p>If a bean definition or singleton instance matching the given name is found,
191      * this method will return {@code true} whether the named bean definition is concrete
192      * or abstract, lazy or eager, in scope or not. Therefore, note that a {@code true}
193      * return value from this method does not necessarily indicate that {@link #getBean}
194      * will be able to obtain an instance for the same name.
195      * @param name the name of the bean to query
196      * @return whether a bean with the given name is present
197      */
198     boolean containsBean(String name);
199 
200     /**
201      * Is this bean a shared singleton? That is, will {@link #getBean} always
202      * return the same instance?
203      * <p>Note: This method returning <code>false</code> does not clearly indicate
204      * independent instances. It indicates non-singleton instances, which may correspond
205      * to a scoped bean as well. Use the {@link #isPrototype} operation to explicitly
206      * check for independent instances.
207      * <p>Translates aliases back to the corresponding canonical bean name.
208      * Will ask the parent factory if the bean cannot be found in this factory instance.
209      * @param name the name of the bean to query
210      * @return whether this bean corresponds to a singleton instance
211      * @throws NoSuchBeanDefinitionException if there is no bean with the given name
212      * @see #getBean
213      * @see #isPrototype
214      */
215     boolean isSingleton(String name) throws NoSuchBeanDefinitionException;
216 
217     /**
218      * Is this bean a prototype? That is, will {@link #getBean} always return
219      * independent instances?
220      * <p>Note: This method returning <code>false</code> does not clearly indicate
221      * a singleton object. It indicates non-independent instances, which may correspond
222      * to a scoped bean as well. Use the {@link #isSingleton} operation to explicitly
223      * check for a shared singleton instance.
224      * <p>Translates aliases back to the corresponding canonical bean name.
225      * Will ask the parent factory if the bean cannot be found in this factory instance.
226      * @param name the name of the bean to query
227      * @return whether this bean will always deliver independent instances
228      * @throws NoSuchBeanDefinitionException if there is no bean with the given name
229      * @since 2.0.3
230      * @see #getBean
231      * @see #isSingleton
232      */
233     boolean isPrototype(String name) throws NoSuchBeanDefinitionException;
234 
235     /**
236      * Check whether the bean with the given name matches the specified type.
237      * More specifically, check whether a {@link #getBean} call for the given name
238      * would return an object that is assignable to the specified target type.
239      * <p>Translates aliases back to the corresponding canonical bean name.
240      * Will ask the parent factory if the bean cannot be found in this factory instance.
241      * @param name the name of the bean to query
242      * @param targetType the type to match against
243      * @return <code>true</code> if the bean type matches,
244      * <code>false</code> if it doesn't match or cannot be determined yet
245      * @throws NoSuchBeanDefinitionException if there is no bean with the given name
246      * @since 2.0.1
247      * @see #getBean
248      * @see #getType
249      */
250     boolean isTypeMatch(String name, Class<?> targetType) throws NoSuchBeanDefinitionException;
251 
252     /**
253      * Determine the type of the bean with the given name. More specifically,
254      * determine the type of object that {@link #getBean} would return for the given name.
255      * <p>For a {@link FactoryBean}, return the type of object that the FactoryBean creates,
256      * as exposed by {@link FactoryBean#getObjectType()}.
257      * <p>Translates aliases back to the corresponding canonical bean name.
258      * Will ask the parent factory if the bean cannot be found in this factory instance.
259      * @param name the name of the bean to query
260      * @return the type of the bean, or <code>null</code> if not determinable
261      * @throws NoSuchBeanDefinitionException if there is no bean with the given name
262      * @since 1.1.2
263      * @see #getBean
264      * @see #isTypeMatch
265      */
266     Class<?> getType(String name) throws NoSuchBeanDefinitionException;
267 
268     /**
269      * Return the aliases for the given bean name, if any.
270      * All of those aliases point to the same bean when used in a {@link #getBean} call.
271      * <p>If the given name is an alias, the corresponding original bean name
272      * and other aliases (if any) will be returned, with the original bean name
273      * being the first element in the array.
274      * <p>Will ask the parent factory if the bean cannot be found in this factory instance.
275      * @param name the bean name to check for aliases
276      * @return the aliases, or an empty array if none
277      * @see #getBean
278      */
279     String[] getAliases(String name);
280 
281 }

View Code