Spring Bean的生命周期

一、生命周期流程图

Spring Bean的完整生命周期从创建Spring容器开始，直到最终Spring容器销毁Bean，这其中包含了一系列关键点：

二、Bean的完整生命周期经历了各种方法调用，这些方法可以划分为以下几类：

1、Bean自身的方法：这个包括了Bean本身调用的方法和通过配置文件中的init-method和destroy-method指定的方法

2、Bean级生命周期接口方法：这个包括了BeanNameAware、BeanFactoryAware、ApplicationContextAware、InitializingBean和DiposableBean这些接口的方法

3、容器级生命周期接口方法：这个包括了InstantiationAwareBeanPostProcessor 和 BeanPostProcessor 这两个接口实现，一般称它们的实现类为“后处理器”。

4、工厂后处理器接口方法：这个包括了AspectJWeavingEnabler, ConfigurationClassPostProcessor, CustomAutowireConfigurer等等非常有用的工厂后处理器　　接口的方法。工厂后处理器也是容器级的。在应用上下文装配配置文件之后立即调用。

三、示例代码

自定义Bean实现BeanNameAware,BeanFactoryAware,ApplicationContextAware,InitializingBean,DisposableBean接口

package com.cuisea.lifecycle;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.*;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * Bean生命周期
 */
public class Person implements BeanNameAware,BeanFactoryAware,ApplicationContextAware,InitializingBean,DisposableBean {
    private String name;
    private String beanName;
    private BeanFactory beanFactory;
    private ApplicationContext applicationContext;

    public Person() {
        System.out.println("【构造器】调用Person的构造器实例化");
    }

    public void setName(String name) {
        this.name = name;
        System.out.println("【注入属性】注入属性name");
    }

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory=beanFactory;
        System.out.println("【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()");
    }

    @Override
    public void setBeanName(String beanName) {
        this.beanName=beanName;
        System.out.println("【BeanNameAware接口】调用BeanNameAware.setBeanName()");
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext=applicationContext;
        System.out.println("【ApplicationContextAware接口】调用ApplicationContextAware.setApplicationContext()");
    }

    @Override
    public void destroy() throws Exception {
        System.out.println("【DiposibleBean接口】调用DiposibleBean.destory()");
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("【InitializingBean接口】调用InitializingBean.afterPropertiesSet()");
    }

    // 通过的init-method属性指定的初始化方法
    public void initMethod() {
        System.out.println("【init-method】调用的init-method属性指定的初始化方法");
    }

    // 通过的destroy-method属性指定的初始化方法
    public void destroyMethod() {
        System.out.println("【destroy-method】调用的destroy-method属性指定的初始化方法");
    }
}

BeanFactoryPostProcessor接口实现类：

package com.cuisea.lifecycle;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

    public MyBeanFactoryPostProcessor() {
        System.out.println("这是BeanFactoryPostProcessor实现类构造器！！");
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory configurableListableBeanFactory) throws BeansException {
        System.out.println("BeanFactoryPostProcessor调用postProcessBeanFactory方法");
        BeanDefinition bd = configurableListableBeanFactory.getBeanDefinition("person");
        bd.getPropertyValues().addPropertyValue("name", "test");
    }
}

BeanPostProcessor接口实现类：

package com.cuisea.lifecycle;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class MyBeanPostProcessor implements BeanPostProcessor {
    public MyBeanPostProcessor() {
        System.out.println("这是BeanPostProcessor实现类构造器！！");
    }

    @Override
    public Object postProcessBeforeInitialization(Object o, String s) throws BeansException {
        System.out.println("BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改！");
        return o;
    }

    @Override
    public Object postProcessAfterInitialization(Object o, String s) throws BeansException {
        System.out.println("BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改！");
        return o;
    }
}

InstantiationAwareBeanPostProcessor接口实现类：

package com.cuisea.lifecycle;

import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;

import java.beans.PropertyDescriptor;

public class MyInstantiationAwareBeanPostProcessor extends InstantiationAwareBeanPostProcessorAdapter {
    public MyInstantiationAwareBeanPostProcessor() {
        super();
        System.out.println("这是InstantiationAwareBeanPostProcessorAdapter实现类构造器！！");
    }

    // 接口方法、实例化Bean之前调用
    @Override
    public Object postProcessBeforeInstantiation(Class beanClass,String beanName) throws BeansException {
        System.out.println("InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法");
        return null;
    }

    // 接口方法、实例化Bean之后调用
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法");
        return bean;
    }

    // 接口方法、设置某个属性时调用
    @Override
    public PropertyValues postProcessPropertyValues(PropertyValues var1, PropertyDescriptor[] var2, Object var3, String var4) throws BeansException{
        System.out.println("InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法");
        return var1;
    }
}

applicationContext.xml

测试代码：

package com.cuisea;

import com.cuisea.lifecycle.Person;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.util.concurrent.TimeUnit;

public class LifeCycleTest {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
        System.out.println("Spring容器初始化成功");
        Person person=(Person)context.getBean("person");
        System.out.println(person);

        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("Spring容器开始关闭");
        context.close();
    }
}

运行结果：

参考：http://www.cnblogs.com/zrtqsk/p/3735273.html 流程中增加了ApplicationContextAware接口