Preface
The life cycle of Spring bean: init (initialization callback), destory (destroy callback). There are four ways to set the callback of the life cycle of the bean:
- 1.@Bean specifies initialization and destruction methods
- 2. Implement the interface
- 3. Use JSR250
- 4. Post-processor interface
Use scenarios:
Actively trigger the event after the bean is initialized. Such as the parameters of the configuration class.
1.@Bean specifies initialization and destruction methods
public class Phone {
private String name;
private int money;
//get set
public Phone() {
super();
("Instantiate the phone");
}
public void init(){
("Initialization method");
}
public void destory(){
("Destruction Method");
}
}@Bean(initMethod = "init",destroyMethod = "destory")
public Phone phone(){
return new Phone();
} AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); ();
Printout:
Instantiate the phone
Initialization method
Destruction method
2. Implement the interface
By allowing Bean to implement InitializingBean (define initialization logic), DisposableBean (define destroy logic) interface
public class Car implements InitializingBean, DisposableBean {
public void afterPropertiesSet() throws Exception {
("After object initialization");
}
public void destroy() throws Exception {
("Object Destruction");
}
public Car(){
("Object initialization");
}
}
Printout:
Object initialization
After the object is initialized
Object Destruction
3. Use JSR250
By defining @PostConstruct (after object initialization) and @PreDestroy (object destruction) annotations on the method
public class Cat{
public Cat(){
("Object Initialization");
}
@PostConstruct
public void init(){
("After object initialization");
}
@PreDestroy
public void destory(){
("Object Destruction");
}
}Printout:
Object Initialization
After the object is initialized
Object Destruction
4. Post-processor interface
public class Dog implements BeanPostProcessor{
public Dog(){
("Object Initialization");
}
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
(beanName+"Before object initialization");
return bean;
}
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
(beanName+"After object initialization");
return bean;
}
}Object Initialization
Before object initialization
After the object is initialized
Before object initialization
After the object is initialized
Summarize
The above is personal experience. I hope you can give you a reference and I hope you can support me more.