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Spring中Bean的生命周期管理

news 2025/8/21 22:44:53

Spring框架中的Bean生命周期是指从创建到销毁的整个过程。在这个过程中，Spring容器会负责管理Bean的状态和行为。以下是Spring中Bean生命周期的详细解释：

实例化：Spring容器根据Bean的定义信息，通过反射机制创建Bean对象。
设置属性值：Spring容器会根据Bean定义中的配置信息，为Bean对象设置属性值。这包括依赖注入的过程。
调用BeanNameAware接口方法：如果Bean实现了BeanNameAware接口，Spring容器会调用setBeanName()方法，将Bean的名称传递给Bean。
调用BeanFactoryAware接口方法：如果Bean实现了BeanFactoryAware接口，Spring容器会调用setBeanFactory()方法，将BeanFactory实例传递给Bean。
调用ApplicationContextAware接口方法：如果Bean实现了ApplicationContextAware接口，Spring容器会调用setApplicationContext()方法，将ApplicationContext实例传递给Bean。
调用BeanPostProcessor的postProcessBeforeInitialization()方法：Spring容器会调用实现了BeanPostProcessor接口的类的postProcessBeforeInitialization()方法，对Bean进行预初始化处理。
调用InitializingBean接口方法：如果Bean实现了InitializingBean接口，Spring容器会调用afterPropertiesSet()方法，用于Bean的初始化操作。
调用自定义的初始化方法：如果在Bean定义中配置了init-method属性，Spring容器会调用指定的初始化方法。
调用BeanPostProcessor的postProcessAfterInitialization()方法：Spring容器会调用实现了BeanPostProcessor接口的类的postProcessAfterInitialization()方法，对Bean进行初始化后的处理。
Bean可以被使用：此时Bean已经初始化完成，可以被应用程序正常使用。
调用DisposableBean接口方法：当容器关闭时，如果Bean实现了DisposableBean接口，Spring容器会调用destroy()方法，用于Bean的资源释放操作。
调用自定义的销毁方法：如果在Bean定义中配置了destroy-method属性，Spring容器会调用指定的销毁方法。
销毁Bean：Spring容器销毁Bean对象，释放内存资源。

总结一下，Spring中Bean的生命周期包括实例化、设置属性值、调用Aware接口方法、调用BeanPostProcessor的前后处理方法、调用InitializingBean和DisposableBean接口方法以及自定义的初始化和销毁方法。在这个过程中，Spring容器负责管理Bean的状态和行为。

以下为示例代码

MyBean

package org.example.bean01.ch01;import org.springframework.beans.BeansException;
import org.springframework.beans.factory.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;@Component
public class MyBean implements ApplicationContextAware, BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean {private String name;private String address;private int phone;private String beanName;private BeanFactory beanFactory;private ApplicationContext context;// 通过<bean>的init-method属性指定的初始化方法public void myInit() {System.out.println("调用<bean>的init-method属性指定的初始化方法");}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.context = applicationContext;System.out.println("调用ApplicationContextAware.setApplicationContext接口");}public String show() {return this.toString();}public MyBean() {System.out.println("调用MyBean的构造器实例化");}public String getName() {return name;}public void setName(String name) {System.out.println("注入属性name");this.name = name;}public String getAddress() {return address;}public void setAddress(String address) {System.out.println("注入属性address");this.address = address;}public int getPhone() {return phone;}public void setPhone(int phone) {System.out.println("注入属性phone");this.phone = phone;}@Overridepublic String toString() {return "MyBean [address=" + address + ", name=" + name + ", phone=" + phone + "]";}// 这是BeanFactoryAware接口方法@Overridepublic void setBeanFactory(BeanFactory arg0) throws BeansException {System.out.println("调用BeanFactoryAware.setBeanFactory()");this.beanFactory = arg0;}// 这是BeanNameAware接口方法@Overridepublic void setBeanName(String arg0) {System.out.println("调用BeanNameAware.setBeanName()");this.beanName = arg0;}// 这是InitializingBean接口方法@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("调用InitializingBean.afterPropertiesSet()");}// 这是DiposibleBean接口方法@Overridepublic void destroy() throws Exception {System.out.println("调用DiposibleBean.destory()");}// 通过<bean>的destroy-method属性指定的初始化方法public void myDestory() {System.out.println("调用<bean>的destroy-method属性指定的初始化方法");}
}

MyBeanFactoryPostProcessor

package org.example.bean01.ch01;import org.springframework.beans.BeansException;
import org.springframework.beans.factory.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;@Component
public class MyBean implements ApplicationContextAware, BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean {private String name;private String address;private int phone;private String beanName;private BeanFactory beanFactory;private ApplicationContext context;// 通过<bean>的init-method属性指定的初始化方法public void myInit() {System.out.println("调用<bean>的init-method属性指定的初始化方法");}@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.context = applicationContext;System.out.println("调用ApplicationContextAware.setApplicationContext接口");}public String show() {return this.toString();}public MyBean() {System.out.println("调用MyBean的构造器实例化");}public String getName() {return name;}public void setName(String name) {System.out.println("注入属性name");this.name = name;}public String getAddress() {return address;}public void setAddress(String address) {System.out.println("注入属性address");this.address = address;}public int getPhone() {return phone;}public void setPhone(int phone) {System.out.println("注入属性phone");this.phone = phone;}@Overridepublic String toString() {return "MyBean [address=" + address + ", name=" + name + ", phone=" + phone + "]";}// 这是BeanFactoryAware接口方法@Overridepublic void setBeanFactory(BeanFactory arg0) throws BeansException {System.out.println("调用BeanFactoryAware.setBeanFactory()");this.beanFactory = arg0;}// 这是BeanNameAware接口方法@Overridepublic void setBeanName(String arg0) {System.out.println("调用BeanNameAware.setBeanName()");this.beanName = arg0;}// 这是InitializingBean接口方法@Overridepublic void afterPropertiesSet() throws Exception {System.out.println("调用InitializingBean.afterPropertiesSet()");}// 这是DiposibleBean接口方法@Overridepublic void destroy() throws Exception {System.out.println("调用DiposibleBean.destory()");}// 通过<bean>的destroy-method属性指定的初始化方法public void myDestory() {System.out.println("调用<bean>的destroy-method属性指定的初始化方法");}
}

MyBeanPostProcessor

package org.example.bean01.ch01;import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;public class MyBeanPostProcessor implements BeanPostProcessor {public MyBeanPostProcessor() {super();System.out.println("调用BeanPostProcessor实现类构造器");}@Overridepublic Object postProcessAfterInitialization(Object arg0, String arg1) throws BeansException {System.out.println("BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改！");return arg0;}@Overridepublic Object postProcessBeforeInitialization(Object arg0, String arg1) throws BeansException {System.out.println("BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改！");return arg0;}
}

AppConfig

package org.example.bean01.ch01;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;@Configuration
@ComponentScan(basePackages = "org.example.bean01.ch01")
public class AppConfig {@Beanpublic MyBeanPostProcessor myBeanPostProcessor() {return new MyBeanPostProcessor();}@Beanpublic MyBeanFactoryPostProcessor myBeanFactoryPostProcessor() {return new MyBeanFactoryPostProcessor();}@Bean(initMethod = "myInit", destroyMethod = "myDestory")public MyBean myBean() {return new MyBean();}}

启动类BeanDemo

package org.example.bean01.ch01;import org.springframework.context.annotation.AnnotationConfigApplicationContext;public class BeanDemo {public static void main(String[] args) {AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);MyBean myBean = context.getBean(MyBean.class);// 使用BeanSystem.out.println("Using bean: " + myBean.show());context.close();}
}