1. bean life cycle
bean creation initialization destroy
Construction (object creation):
Single instance: create an object when the container starts;
Multi instance: create an object every time you get it;
Initialization:
The object is created and assigned. Call the initialization method.
Destruction:
Single instance, when the container is closed;
Multi instance: the container does not manage the bean, and the container calls the destroy method.
2. User defined initialization method and destruction method
2.1. Specify initmethod and destroymethod through @ Bean
- Mainconfiglife cycle class
@Configuration
public class MainConfigLifeCycle {
@Bean(initMethod = "init", destroyMethod = "destroy")
public Car car() {
return new Car();
}
}
- Class Car
public class Car {
public Car() {
System.out.println("new car");
}
public void init() {
System.out.println("car init");
}
public void destroy() {
System.out.println("car destroy");
}
}
- Ioctest life cycle class
@Test
public void test1() {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigLifeCycle.class);
System.out.println("Container initialization");
context.close();
}
2.2. By enabling the bean to implement the InitializingBean interface (define the initialization interface), the DisposableBean interface (destroy interface)
- Class Cat
@Component
public class Cat implements InitializingBean,DisposableBean {
public Cat() {
System.out.println("new cat");
}
public void destroy() throws Exception {
System.out.println("cat destroy");
}
public void afterPropertiesSet() throws Exception {
System.out.println("cat afterPropertiesSet");
}
}
- Mainconfiglife cycle class
@ComponentScan("com.dav.bean")
@Configuration
public class MainConfigLifeCycle {
}
- Ioctest life cycle class
@Test
public void test1() {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigLifeCycle.class);
System.out.println("Container initialization");
context.close();
}
2.3. JSR250 annotation using JAVA
@PostConstruct: execute initialization method after bean creation and property assignment;
@PreDestroy: inform us to clean up the bean before the container destroys it;
- Class Dog
@Component
public class Dog {
public Dog() {
System.out.println("new dog");
}
@PostConstruct
public void init() {
System.out.println("dog @PostConstruct");
}
@PreDestroy
public void destroy() {
System.out.println("dog @PreDestroy");
}
}
- Mainconfiglife cycle class
@ComponentScan("com.dav.bean")
@Configuration
public class MainConfigLifeCycle {
}
- Ioctest life cycle class
@Test
public void test1() {
AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigLifeCycle.class);
System.out.println("Container initialization");
context.close();
}
