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spring入門（4） spring中Bean的生命周期總結

編輯：關於JAVA

Spring中Bean的生命周期,在學習spring的過程中bean的生命周期理解對學習spring有很大的幫助，下面我就分別介紹在 ApplicationContext和BeanFactory中Bean的生命周期。

1、在ApplicationContext中Bean的生命周期

生命周期執行的過程如下：

1、需找所有的bean根據bean定義的信息來實例化bean

2、使用依賴注入，spring按bean 定義信息配置bean的所有屬性

3、若bean實現了BeanNameAware接口，工廠調用Bean的setBeanName（）方法傳遞bean 的ID。

4、若bean實現了BeanFactoryAware接口，工廠調用setBeanFactory（）方法傳入工廠自身。

5、若 bean實現了ApplicationContextAware()接口，setApplicationContext()方法會被調用

6、若BeanPostProcessor和 bean關聯,

則它們的postProcessBeforeInitialization()方法被調用

7、若bean指定了init- method="init"方法、，它將被調用。

8、若有BeanPostProcessor和bean關聯，

則它們的 postProcessAfterInitialization()方法被調用

注意：通過已上操作,此時的Bean就可以被應用的系統使用，並講保留在BeanFactory工廠中直到不再需要為止.但我們也可以通過9或者10進行銷毀

9、若bean實現了DisposableBean接口,distroy()方法被調用

10、如果指定了destroy-method="close"定制的銷毀方法，就調用這個方法

案例分析：

創建一個實體Bean代碼如下：

package www.csdn.spring.dao;  
      
      
import org.springframework.beans.BeansException;  
      
import org.springframework.beans.factory.BeanFactory;  
      
import org.springframework.beans.factory.BeanFactoryAware;  
      
import org.springframework.beans.factory.BeanNameAware;  
      
import org.springframework.beans.factory.DisposableBean;  
      
import org.springframework.beans.factory.InitializingBean;  
      
import org.springframework.context.ApplicationContext;  
      
import org.springframework.context.ApplicationContextAware;  
      
      
public class HelloDaoImpl implements BeanNameAware, BeanFactoryAware,  
      
InitializingBean, ApplicationContextAware, DisposableBean {  
      
      
private String content;  
      
      
public HelloDaoImpl() {  
      
System.out.println("----------HelloDaoImpl實例化");  
      
}  
      
      
public void setContent(String content) {  
      
System.out.println("----------通過依賴注入的內容是:" + content);  
      
this.content = content;  
      
}  
      
      
@Override
      
public void setBeanName(String beanId) {  
      
System.out.println("----------輸出BeanId:" + beanId);  
      
}  
      
      
@Override
      
public void setBeanFactory(BeanFactory factory) throws BeansException {  
      
System.out.println("----------factory:" + factory.getClass());  
      
      
}  
      
      
@Override
      
public void setApplicationContext(ApplicationContext applicationContext)  
      
throws BeansException {  
      
System.out.println("----------" + applicationContext);  
      
      
}  
      
      
@Override
      
public void afterPropertiesSet() throws Exception {  
      
System.out.println("----------afterPropertiesSet");  
      
}  
      
      
public void init() {  
      
System.out.println("----------初始化方法");  
      
}  
      
      
@Override
      
public void destroy() throws Exception {  
      
System.out.println("----------bean被銷毀");  
      
      
}  
      
      
public void close() {  
      
System.out.println("----------close");  
      
}  
      
      
}

package www.csdn.spring.dao;  
      
      
import org.springframework.beans.BeansException;  
      
import org.springframework.beans.factory.BeanFactory;  
      
import org.springframework.beans.factory.BeanFactoryAware;  
      
import org.springframework.beans.factory.BeanNameAware;  
      
import org.springframework.beans.factory.DisposableBean;  
      
import org.springframework.beans.factory.InitializingBean;  
      
import org.springframework.context.ApplicationContext;  
      
import org.springframework.context.ApplicationContextAware;  
      
      
public class HelloDaoImpl implements BeanNameAware, BeanFactoryAware,  
      
InitializingBean, ApplicationContextAware, DisposableBean {  
      
      
private String content;  
      
      
public HelloDaoImpl() {  
      
System.out.println("----------HelloDaoImpl實例化");  
      
}  
      
      
public void setContent(String content) {  
      
System.out.println("----------通過依賴注入的內容是:" + content);  
      
this.content = content;  
      
}  
      
      
@Override
      
public void setBeanName(String beanId) {  
      
System.out.println("----------輸出BeanId:" + beanId);  
      
}  
      
      
@Override
      
public void setBeanFactory(BeanFactory factory) throws BeansException {  
      
System.out.println("----------factory:" + factory.getClass());  
      
      
}  
      
      
@Override
      
public void setApplicationContext(ApplicationContext applicationContext)  
      
throws BeansException {  
      
System.out.println("----------" + applicationContext);  
      
      
}  
      
      
@Override
      
public void afterPropertiesSet() throws Exception {  
      
System.out.println("----------afterPropertiesSet");  
      
}  
      
      
public void init() {  
      
System.out.println("----------初始化方法");  
      
}  
      
      
@Override
      
public void destroy() throws Exception {  
      
System.out.println("----------bean被銷毀");  
      
      
}  
      
      
public void close() {  
      
System.out.println("----------close");  
      
}  
      
      
}

創建BeanPostProcessor實現類

package www.csdn.spring.dao;  
      
      
import org.springframework.beans.BeansException;  
      
import org.springframework.beans.factory.config.BeanPostProcessor;  
      
      
public class BeanPostProcessorImpl implements BeanPostProcessor {  
      
@Override
      
public Object postProcessBeforeInitialization(Object bean, String beanName)  
      
throws BeansException {  
      
System.out.println("我把:" + beanName + "實例化化之前的操作");  
      
return bean;  
      
}  
      
      
@Override
      
public Object postProcessAfterInitialization(Object bean, String beanName)  
      
throws BeansException {  
      
System.out.println("我把:" + beanName + "實例化化之後的操作");  
      
return bean;  
      
}  
      
      
}

package www.csdn.spring.dao;  
      
      
import org.springframework.beans.BeansException;  
      
import org.springframework.beans.factory.config.BeanPostProcessor;  
      
      
public class BeanPostProcessorImpl implements BeanPostProcessor {  
      
@Override
      
public Object postProcessBeforeInitialization(Object bean, String beanName)  
      
throws BeansException {  
      
System.out.println("我把:" + beanName + "實例化化之前的操作");  
      
return bean;  
      
}  
      
      
@Override
      
public Object postProcessAfterInitialization(Object bean, String beanName)  
      
throws BeansException {  
      
System.out.println("我把:" + beanName + "實例化化之後的操作");  
      
return bean;  
      
}  
      
      
}

在配置文件中配置實體Bean和BeanPostProcessorImpl 特殊的Bean

<?xml version="1.0" 

encoding="UTF-8"?>  
      
<beans xmlns="http://www.springframework.org/schema/beans"
      
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      
xsi:schemaLocation="http://www.springframework.org/schema/beans  
      
           http://www.springframework.org/schema/beans/spring-beans.xsd">  
      
      
      
<!-- spring容器 就是負責創建、管理、維護Bean 並且能夠依賴注入到相應組件上 -->
      
<bean id="helloDaoImpl" class="www.csdn.spring.dao.HelloDaoImpl"
      
scope="singleton" lazy-init="false" init-method="init" destroy-method="close">  
      
<!-- 通過set方法注入 -->
      
<property name="content" value="陳老師早上好！"   />  
      
</bean>  
      
      
<!-- BeanPostProcessor與當前的bean都進行關聯 -->
      
<bean class="www.csdn.spring.dao.BeanPostProcessorImpl"   />  
      
      
</beans>

<?xml version="1.0" encoding="UTF-8"?>  
      
<beans xmlns="http://www.springframework.org/schema/beans"
      
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      
xsi:schemaLocation="http://www.springframework.org/schema/beans  
      
           http://www.springframework.org/schema/beans/spring-beans.xsd">  
      
      
      
<!-- spring容器 就是負責創建、管理、維護Bean 並且能夠依賴注入到相應組件上 -->
      
<bean id="helloDaoImpl" class="www.csdn.spring.dao.HelloDaoImpl"
      
scope="singleton" lazy-init="false" init-method="init" destroy-method="close">  
      
<!-- 通過set方法注入 -->
      
<property name="content" value="陳老師早上好！"   />  
      
</bean>  
      
      
<!-- BeanPostProcessor與當前的bean都進行關聯 -->
      
<bean class="www.csdn.spring.dao.BeanPostProcessorImpl"   />  
      
      
</beans>

創建測試類BeanTest

package www.csdn.spring.bean.cycle;  
      
      
import org.junit.Test;  
      
import org.springframework.context.ApplicationContext;  
      
import org.springframework.context.ConfigurableApplicationContext;  
      
import org.springframework.context.support.ClassPathXmlApplicationContext;  
      
      
public class BeanTest {  
      
      
@Test
      
public void test() {  
      
ApplicationContext context = new ClassPathXmlApplicationContext(  
      
"classpath:spring-dao.xml");  
      
// 強制造型   
      
ConfigurableApplicationContext cont = (ConfigurableApplicationContext) context;  
      
// 執行關閉 可以考到 destory-method的方法的執行   
      
cont.close();  
      
      
}  
      
}

package www.csdn.spring.bean.cycle;  
      
      
import org.junit.Test;  
      
import org.springframework.context.ApplicationContext;  
      
import org.springframework.context.ConfigurableApplicationContext;  
      
import org.springframework.context.support.ClassPathXmlApplicationContext;  
      
      
public class BeanTest {  
      
      
@Test
      
public void test() {  
      
ApplicationContext context = new ClassPathXmlApplicationContext(  
      
"classpath:spring-dao.xml");  
      
// 強制造型  
      
ConfigurableApplicationContext cont = (ConfigurableApplicationContext) context;  
      
// 執行關閉 可以考到 destory-method的方法的執行  
      
cont.close();  
      
      
}  
      
}

執行結果如下：

總結：在ApplicationContext中Bean的生命周期

2、在 BeanFactory中Bean的生命周期

在BeanFactory中Bean的生命周期與ApplicationContext中bean的生命周期唯一不同的是：若bean實現了ApplicationContextAware()接口，在ApplicationContext中bean的生命周期中 setApplicationContext()方法會被調用,而在BeanFactory中Bean的生命周期此方法不會被調用。

案例采用上個案例：測試類中測試代碼如下：

// 創建資源對象   
      
ClassPathResource resource = new ClassPathResource("spring-dao.xml");  
      
// 采用BeanFactory初始化容器   
      
ConfigurableBeanFactory cbf = new XmlBeanFactory(resource);  
      
// bean後置處理器必須通過addBeanPostProcessor(new BeanPostProcessorImpl())手動添加   
      
cbf.addBeanPostProcessor(new BeanPostProcessorImpl());  
      
//在配置文件中給BeanPostProcessorImpl的bean加上id="beanPostProcessorImpl" //cbf.addBeanPostProcessor

(cbf.getBean("beanPostProcessorImpl", BeanPostProcessorImpl.class));   
      
// 獲取Bean對象   
      
cbf.getBean("helloDaoImpl", HelloDaoImpl.class);  
      
// 銷毀   
      
cbf.destroySingletons();

// 創建資源對象  
      
ClassPathResource resource = new ClassPathResource("spring-dao.xml");  
      
// 采用BeanFactory初始化容器  
      
ConfigurableBeanFactory cbf = new XmlBeanFactory(resource);  
      
// bean後置處理器必須通過addBeanPostProcessor(new BeanPostProcessorImpl())手動添加  
      
cbf.addBeanPostProcessor(new BeanPostProcessorImpl());  
      
//在配置文件中給BeanPostProcessorImpl的bean加上id="beanPostProcessorImpl" //cbf.addBeanPostProcessor

(cbf.getBean("beanPostProcessorImpl", BeanPostProcessorImpl.class));  
      
// 獲取Bean對象  
      
cbf.getBean("helloDaoImpl", HelloDaoImpl.class);  
      
// 銷毀  
      
cbf.destroySingletons();

執行結果：