转Spring中@PostConstruct、@PreDestroy、InitializingBean、DisposableBean、initMethod、de

这次的博客比较Spring中@PostConstruct、@PreDestroy、InitializingBean、DisposableBean、initMethod、destoryMethod的执行顺序，顺便会将construct以及与注入顺序一并比较

 

为了方便起见，这次不使用xml文件定义bean，完全采用注解配置，共3个类，都放在annotations包下

下面是定义的两个bean，Bean2直接加上@Conponent注解，加入到ioc容器

而Bean1，有1个注入属性、1个普通属性、1个构造器、3个初始化方法、3个销毁方法

public class Bean1 implements InitializingBean, DisposableBean{

    @Autowired
    public Bean2 bean2;

    public String state;

    public Bean1 (){
        state = "construct!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    public void init_method (){
        state = "init-method!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    public void destory_method (){
        state = "destory-method!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    @PostConstruct
    public void postConstruct (){
        state = "postConstruct!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    @PreDestroy
    public void preDestory (){
        state = "preDestory!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    @Override
    public void destroy() throws Exception {
        state = "destory!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        state = "afterPropertiesSet!";
        System.out.println("bean1 -> " + state + "..." + "bean2: " + bean2);
    }

}

@Component
public class Bean2 {

}

 

不要奇怪为什么Bean1没有加入到ioc容器，我们下面马上进行：

@Configuration
@org.springframework.context.annotation.ComponentScan(basePackages = "annotations")
public class ComponentScan {

    @Bean(initMethod = "init_method", destroyMethod = "destory_method")
    public Bean1 bean1 (){
        return new Bean1();
    }

    public static void main(String[] args) {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
        ctx.register(ComponentScan.class);
        ctx.refresh();
        ctx.registerShutdownHook();
    }

}

 可以通过@Configuration注册bean，和xml是一样的效果

 

打印结果为

bean1 -> construct!...bean2: null
bean1 -> postConstruct!...bean2: annotations.Bean2@35fc6dc4
bean1 -> afterPropertiesSet!...bean2: annotations.Bean2@35fc6dc4
bean1 -> init-method!...bean2: annotations.Bean2@35fc6dc4
bean1 -> preDestory!...bean2: annotations.Bean2@35fc6dc4
bean1 -> destory!...bean2: annotations.Bean2@35fc6dc4
bean1 -> destory-method!...bean2: annotations.Bean2@35fc6dc4

 

所以执行顺序如下：

初始化时：构造器Construct  ->  属性注入  ->  @PostConstruct  ->  InitializingBean接口  ->  bean定义的initMethod 

销毁时：@PreDestroy  ->  DisposableBean接口 ->  bean定义的destoryMethod

 

When you work directly in Java, you can do anything you like with your objects and do not always need to rely on the container lifecycle!