Initialization and destruction methods of bean

1, bean life cycle: 
　　bean creation --- ---- initialization process of the destruction of 
　　container-managed bean life cycle; 
　　we can customize the initialization and destruction methods; in the bean container to the current life cycle time to call us from initialization and destruction methods defined. 
2, specify the initialization and destruction methods;

　　Specifies the init-method and destroy-method by @Bean;
    Initialization: After the object is created, and assigned a good initialization method is called (single instance or multi-instance); 
   destruction methods: single-instance: when the object is destroyed or closed container calls this method; 
 　　　　　　multi-instance: the container does not manage bean, so it will not call the destruction methods.

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

In the bean to a container:

@Configuration
public class MainConfigOfLifeCycle {
    
    //@Scope("prototype")
    @Bean(initMethod="init",destroyMethod="detory")
    public Car car(){
        return new Car();
    }

}

3, achieved by having the InitializingBean Bean (defined initialization logic) ------ afterPropertiesSet () method,

　　           The DisposableBean (defined logical destruction) --- the destroy () method;

@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...");
    }
}

4, may be used JSR250;

　　@PostConstruct: Creating the bean is complete and the property assignment is completed; to perform initialization method

　　@PreDestroy: let us work to clean up before the destruction of bean container

@Component
 public  class Dog {
     public Dog () { 
        System.out.println ( "Dog constructor ..." ); 
    } 
    // After the object is created and assigned call 
    @PostConstruct
     public  void the init () { 
        System.out.println ( " the PostConstruct @ .... ... Dog " ); 
    } 
    // container before removing the object 
    @PreDestroy
     public  void detory () { 
        System.out.println ( " Dog The PreDestroy @ .... ... " ); 
    } 
}

5, Spring provides us with BeanPostProcessor, bean post-processors

[BeanPostProcessor] interface: bean post-processor; 
　　some initialization processing before and after the bean; 
　　postProcessBeforeInitialization: work before initialization 
　　postProcessAfterInitialization: after initialization work

/ ** 
 * postprocessor: before and after the initialization processing 
 * The postprocessor was added to the vessel * / 
@Component 
public  class MyBeanPostProcessor the implements the BeanPostProcessor { 

    @Override 
    public Object postProcessBeforeInitialization (Object the bean, the beanName String) throws BeansException {
         / / the TODO Auto-Generated Stub Method 
        System.out.println ( "postProcessBeforeInitialization ..." the beanName + + "=>" + the bean);
         return the bean; 
    } 

    @Override 
    public Object postProcessAfterInitialization (Object the bean, the beanName String) throws BeansException {
        // TODO Auto-generated method stub
        System.out.println("postProcessAfterInitialization..."+beanName+"=>"+bean);
        return bean;
    }
}

Initialization and destruction methods of bean

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