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!