Spring的几种初始化和销毁方法

一 指定初始化和销毁方法

通过@Bean指定init-method和destroy-method；

@Bean(initMethod="init",destroyMethod="detory")
    public Car car(){
        return new Car();
    }

二 通过让Bean实现InitializingBean（定义初始化逻辑）

@Component
public class Cat implements InitializingBean,DisposableBean {
    
    public Cat(){
        System.out.println("cat constructor...");
    }
​
    @Override
    public void destroy() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("cat...destroy...");
    }
​
    @Override
    public void afterPropertiesSet() throws Exception {
        // TODO Auto-generated method stub
        System.out.println("cat...afterPropertiesSet...");
    }
​
}

三 可以使用JSR250

@PostConstruct：在bean创建完成并且属性赋值完成；来执行初始化方法

@PreDestroy：在容器销毁bean之前通知我们进行清理工作

@Component
public class Dog implements ApplicationContextAware {
    
    //@Autowired
    private ApplicationContext applicationContext;
    
    public Dog(){
        System.out.println("dog constructor...");
    }
    
    //对象创建并赋值之后调用
    @PostConstruct
    public void init(){
        System.out.println("Dog....@PostConstruct...");
    }
    
    //容器移除对象之前
    @PreDestroy
    public void detory(){
        System.out.println("Dog....@PreDestroy...");
    }
​
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        // TODO Auto-generated method stub
        this.applicationContext = applicationContext;
    }
​
}

四 可以使用BeanPostProcessor

/**
 * 后置处理器：初始化前后进行处理工作
 * 将后置处理器加入到容器中
 * 在bean初始化前后进行一些处理工作；
 * postProcessBeforeInitialization:在初始化之前工作
 * postProcessAfterInitialization:在初始化之后工作
 */
@Component
public class MyBeanPostProcessor implements BeanPostProcessor,Ordered {
​
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("postProcessBeforeInitialization..."+beanName+"=>"+bean);
        return bean;
    }
​
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("postProcessAfterInitialization..."+beanName+"=>"+bean);
        return bean;
    }
​
    @Override
    public int getOrder() {
        return 2;
    }
​
}