@[TOC]

1 指定初始化和销毁方法

• 创建Car类

  public class Car {
       
  
    public Car() {
       
        System.out.println("car constructor......");
    }
  
    public void init(){
       
        System.out.println("car ...init...");
    }
  
    public void destory(){
       
        System.out.println("car ...destory...");
    }
  }
  

• 写配置类

  @Configuration
  public class MainConfigOfLifeCycle {
       
  
    @Bean(value = "car",initMethod="init",destroyMethod = "destory")
    public Car car(){
       
        return new Car();
    }
  }
  

• 测试

  @Test
    public void test01(){
       
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigOfLifeCycle.class);
        System.out.println("容器创建完成");
        context.close();
    }
  

  2 使用接口InitializingBean和DisposableBean实现初始化和销毁

• 新建Cat类实现接口InitializingBean和DisposableBean
  ```java
  import org.springframework.beans.factory.DisposableBean;
  import org.springframework.beans.factory.InitializingBean;
  import org.springframework.stereotype.Component;

@Component
public class Cat implements InitializingBean, DisposableBean {

public Cat() {
    System.out.println("cat constructor....");
}

//容器关闭时调用
@Override
public void destroy() throws Exception {
    System.out.println("cat ... destroy ....");
}

//Bean创建完成，并且属性都复制后执行
@Override
public void afterPropertiesSet() throws Exception {
    System.out.println("cat ... afterPropertiesSet ...");
}

}

* 注入IOC容器
```java
@Configuration
@ComponentScan("com.yunfeng.spring2.entity")
public class MainConfigOfLifeCycle {}

• 测试

  @Test
    public void test01(){
       
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigOfLifeCycle.class);
        System.out.println("容器创建完成");
        context.close();
    }
  

  3 使用JSR250中的@PreDestroy 和@PostConstruct

  ```java
  import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@Component
public class Dog {

public Dog() {
    System.out.println("Dog constructor....");
}

//容器关闭时调用
@PreDestroy
public void destroy() throws Exception {
    System.out.println("Dog ... destroy ....");
}

//Bean创建完成，并且属性都复制后执行
@PostConstruct
public void afterPropertiesSet() throws Exception {
    System.out.println("Dog ... PostConstruct ...");
}

}

# 4 BeanPostProcessor后置处理器
* 在bean初始化前后进行一些处理工作
```java
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;

/**
 * 后置处理器：初始化前后进行处理工作
 */
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
    //初始化前执行
    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("postProcessBeforeInitialization..." + beanName + bean);
        return bean;
    }

    //初始化后执行
    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("postProcessAfterInitialization..." + beanName + bean);
        return bean;
    }
}