Spring 使用介绍（十三）—— Bean的生命周期

一、概述

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，生命周期时序图如下：

二、生命周期接口分类

Bean的生命周期经历了多个接口方法的调用，这些接口和方法可分为以下四类：

1、Bean自身方法

　　通过<bean>的init-method和destroy-method或注解@PostConstruct与@PreDestroy 指定的方法

2、Bean级生命周期接口

　　包括BeanNameAware、BeanFactoryAware、InitializingBean、DiposableBean

// 获取bean名称
public interface BeanNameAware extends Aware {
    void setBeanName(String name);
}

// 获取BeanFactory对象
public interface BeanFactoryAware extends Aware {
    void setBeanFactory(BeanFactory beanFactory) throws BeansException;
}

// 对象初始化，与init-method属性作用相同
public interface InitializingBean {
    void afterPropertiesSet() throws Exception;
}

// 对象销毁，与destroy-method属性作用相同
public interface DisposableBean {
    void destroy() throws Exception;
}

3、容器级生命周期接口

　　包括InstantiationAwareBeanPostProcessor 、BeanPostProcessor

// 对象实例化生命周期接口
public interface InstantiationAwareBeanPostProcessor extends BeanPostProcessor {
    Object postProcessBeforeInstantiation(Class<?> beanClass, String beanName) throws BeansException;
    boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException;
    PropertyValues postProcessPropertyValues(
            PropertyValues pvs, PropertyDescriptor[] pds, Object bean, String beanName)
            throws BeansException;
}

// 对象初始化生命周期接口
public interface BeanPostProcessor {
    Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException;
    Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException;
}

4、BeanFactory后处理器接口

　　包括BeanFactoryPostProcessor

// 工厂后处理接口，用于修改bean配置（BeanDefinition）
public interface BeanFactoryPostProcessor {
    void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;
}

三、生命周期示例演示

Bean

@Component
public class Person implements BeanFactoryAware, BeanNameAware, InitializingBean, DisposableBean {
    
    private String name;
    
    @Value("shanghai")
    private String address;
    
    @Value("123")
    private int phone;

    private BeanFactory beanFactory;
    private String beanName;

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

    public String getName() {
        return name; 
    }

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

    @Override
    public String toString() {
        return "Person [address=" + address + ", name=" + name + ", phone="
                + phone + "]";
    }

    // 这是BeanFactoryAware接口方法
    @Override
    public void setBeanFactory(BeanFactory arg0) throws BeansException {
        System.out
                .println("【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()");
        this.beanFactory = arg0;
    }

    // 这是BeanNameAware接口方法
    @Override
    public void setBeanName(String arg0) {
        System.out.println("【BeanNameAware接口】调用BeanNameAware.setBeanName()");
        this.beanName = arg0;
    }

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

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

    // 通过<bean>的init-method属性指定的初始化方法
    @PostConstruct
    public void myInit() {
        System.out.println("【init-method】调用<bean>的init-method属性指定的初始化方法");
    }

    // 通过<bean>的destroy-method属性指定的初始化方法
    @PreDestroy
    public void myDestory() {
        System.out.println("【destroy-method】调用<bean>的destroy-method属性指定的初始化方法");
    }
}

View Code

BeanFactoryPostProcessor

@Component
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

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

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory arg0)
            throws BeansException {
        System.out
                .println("BeanFactoryPostProcessor调用postProcessBeanFactory方法");
        BeanDefinition bd = arg0.getBeanDefinition("person");
        bd.getPropertyValues().addPropertyValue("phone", "110");
    }

}

View Code

InstantiationAwareBeanPostProcessor

@Component
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 boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
        System.out.println("InstantiationAwareBeanPostProcessor调用postProcessAfterInstantiation方法");
        return true;
    }

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

View Code

BeanPostProcessor

@Component
public class MyBeanPostProcessor implements BeanPostProcessor {

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

    @Override
    public 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;
    }

    @Override
    public 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;
    }
}

View Code

配置

<context:component-scan base-package="cn.matt.lifecircle"/>

测试

public class BeanLifeTest {

    @Test
    public void test() {
        System.out.println("现在开始初始化容器");
        
        ApplicationContext factory = new ClassPathXmlApplicationContext("spring-context-lifecircle.xml");
        System.out.println("容器初始化成功");    
        //得到Preson，并使用
        Person person = factory.getBean("person",Person.class);
        System.out.println(person);
        
        System.out.println("现在开始关闭容器！");
        ((ClassPathXmlApplicationContext)factory).registerShutdownHook();
    }
}

View Code

运行结果

现在开始初始化容器
这是BeanFactoryPostProcessor实现类构造器！！
BeanFactoryPostProcessor调用postProcessBeanFactory方法
这是BeanPostProcessor实现类构造器！！
这是InstantiationAwareBeanPostProcessorAdapter实现类构造器！！
InstantiationAwareBeanPostProcessor调用postProcessBeforeInstantiation方法
【构造器】调用Person的构造器实例化
InstantiationAwareBeanPostProcessor调用postProcessAfterInstantiation方法
InstantiationAwareBeanPostProcessor调用postProcessPropertyValues方法
【注入属性】注入属性name
【注入属性】注入属性phone
【BeanNameAware接口】调用BeanNameAware.setBeanName()
【BeanFactoryAware接口】调用BeanFactoryAware.setBeanFactory()
BeanPostProcessor接口方法postProcessBeforeInitialization对属性进行更改！
【init-method】调用<bean>的init-method属性指定的初始化方法
【InitializingBean接口】调用InitializingBean.afterPropertiesSet()
BeanPostProcessor接口方法postProcessAfterInitialization对属性进行更改！
InstantiationAwareBeanPostProcessor调用postProcessAfterInitialization方法
容器初始化成功
Person [address=shanghai, name=matt, phone=110]
现在开始关闭容器！
【destroy-method】调用<bean>的destroy-method属性指定的初始化方法
【DiposibleBean接口】调用DiposibleBean.destory()

四、一个应用示例

Spring 使用介绍（十三）—— Bean的生命周期

猜你喜欢