Spring Bean在BeanFactory生命周期

生命周期过程

• 如果容器注册InstantiationAwareBeanPostProcessor接口，调用postProcessBeforeInstantiation方法
• Bean的实例化(调用默认构造器)
• 如果容器注册InstantiationAwareBeanPostProcessor接口，调用postProcessAfterInstantiation方法
• 如果容器注册InstantiationAwareBeanPostProcessor接口，调用postProcessPropertyValues方法
• 根据配置设置属性值
• 如果Bean实现了BeanNameAware接口，调用BeanNameAware接口的setBeanName方法
• 如果Bean实现了BeanFactoryAware 接口，调用BeanFactoryAware 接口的setBeanFactory方法
• 如果容器注册了BeanPostProcessor接口，调用BeanPostProcessor接口的postProcessBeforeInitialization方法
• 如果Bean实现了InitializingBean接口，调用InitializingBean接口的afterPropertiesSet方法
• 通过init-method属性配置的初始方法
• 如果容器注册了BeanPostProcessor接口，调用BeanPostProcessor接口的postProcessAfterInitialization 方法
• 如果是单例模式，将Bean放入缓存池中；容器销毁时，调用DisposableBean的destroy方法；最后调用destroy-method方法
• 如果是多例模式，将Bean交给调用者。

测试

package exa.ydoing.spring;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
public class App {
    public static void main(String[] args) {
        //实例化BeanFactory
        Resource res = new ClassPathResource("ApplicationContext.xml");
        BeanFactory bf = new XmlBeanFactory(res);

        //注册InstantiationAwareBeanPostProcessor后置处理器，因为InstantiationAwareBeanPostProcessor继承了BeanPostProcessor，
        //所以不再单独注册BeanPostProcessor后置处理器
        ((ConfigurableBeanFactory)bf).addBeanPostProcessor(new MyInstantiationAwareBeanPostProcessor());

        //获得bean
        MyBean bean = bf.getBean("myBean", MyBean.class);
        bean.printName();

        //销毁所有Bean
        ((XmlBeanFactory)bf).destroySingletons();
    }
}

---

InstantiationAwareBeanPostProcessor 的实现：

package exa.ydoing.spring;
import java.beans.PropertyDescriptor;
import org.springframework.beans.BeansException;
import org.springframework.beans.PropertyValues;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor;
public class MyInstantiationAwareBeanPostProcessor implements InstantiationAwareBeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("调用BeanPostProcessor接口的postProcessBeforeInitialization方法");
        return bean;
    }
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("调用BeanPostProcessor接口的postProcessAfterInitialization方法");
        return bean;
    }
    @Override
    public Object postProcessBeforeInstantiation(Class beanClass, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("调用InstantiationAwareBeanPostProcessor接口的postProcessBeforeInstantiation方法");
        return null;
    }
    @Override
    public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("调用InstantiationAwareBeanPostProcessor接口的postProcessAfterInstantiation方法");
        return true;
    }
    @Override
    public PropertyValues postProcessPropertyValues(PropertyValues pvs, PropertyDescriptor[] pds, Object bean,
            String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("调用InstantiationAwareBeanPostProcessor接口的postProcessPropertyValues方法");
        return pvs;
    }
}

---

MyBean的代码：

package exa.ydoing.spring;
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;
public class MyBean implements BeanNameAware, BeanFactoryAware, InitializingBean, DisposableBean{
    private BeanFactory beanFactory;

    private String name;

    private String tag;

    public MyBean(){
        System.out.println("调用构造器实例化Bean");
    }

    public void printName(){
        System.out.println("MyBean name is: " + name);
    }

    public String getTag() {
        return tag;
    }
    public void setTag(String tag) {
        this.tag = tag;
        System.out.println("设置Bean的属性为：" + tag);
    }
    @Override
    public void destroy() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("调用DisposableBean接口的destroy方法");
    }
    @Override
    public void afterPropertiesSet() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("调用InitializingBean接口的afterPropertiesSet方法");
    }
    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        // TODO Auto-generated method stub
        this.beanFactory = beanFactory;
        System.out.println("调用BeanFactoryAware接口的setBeanFactory方法");
    }
    @Override
    public void setBeanName(String name) {
        // TODO Auto-generated method stub
        this.name = name;
        System.out.println("调用BeanNameAware接口的setBeanName方法");
    }
}

---

Bean的配置很简单：

  id="myBean" class="exa.ydoing.spring.MyBean">
      <property name="tag" value="test"/>
    

---

输出：

调用InstantiationAwareBeanPostProcessor接口的postProcessBeforeInstantiation方法
调用构造器实例化Bean
调用InstantiationAwareBeanPostProcessor接口的postProcessAfterInstantiation方法
调用InstantiationAwareBeanPostProcessor接口的postProcessPropertyValues方法
设置Bean的属性为：test
调用BeanNameAware接口的setBeanName方法
调用BeanFactoryAware接口的setBeanFactory方法
调用BeanPostProcessor接口的postProcessBeforeInitialization方法
调用InitializingBean接口的afterPropertiesSet方法
调用BeanPostProcessor接口的postProcessAfterInitialization方法
MyBean name is: myBean
调用DisposableBean接口的destroy方法