@PostConstruct 和 @PreDestroy 注释不起作用

Question

I have TennisCoach class:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

@Component
public class TennisCoach implements Coach {
    @Autowired
    @Qualifier("randomFortuneService")
    private FortuneService fortuneService;

    public TennisCoach() {
        System.out.println("Inside default constructor");
    }

    @PostConstruct
    public void doMyStartupStuff() {
        System.out.println("Inside postconstructor");
    }

    @PreDestroy
    public void doMyFinalStuff() {
        System.out.println("Inside predestroyer");
    }

    @Override
    public String getDailyFortune() {
        return fortuneService.getFortune();
    }

    @Override
    public String getDailyWorkout() {
        return "Practice your backhand volley";
    }
}

And such main class:

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AnnotationBeanScopeDemoApp {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context =
                new ClassPathXmlApplicationContext("applicationContext.xml");

        Coach theCoach = context.getBean("tennisCoach", Coach.class);

        System.out.println(theCoach.getDailyFortune());
        System.out.println(theCoach.getDailyWorkout());

        context.close();
    }
}

Expected output is:

Inside default constructor

Inside postconstructor

DailyFortune

Practice your backhand volley

Inside predestroyer

But I get this:

Inside default constructor

DailyFortune

Practice your backhand volley

It seems like @PostContruct and @PreDestroy annotations do not work correctly. I cannot find the reason of my problem.

Answer 1

Spring might not handle JSR-250 lifecycle annotations by default. Check your applicationContext.xml that it has element:

<beans ...
    <context:annotation-config/>
    ....
</beans>

that configures Spring to be aware of @PostConstruct & @PrePersist .

Fo more info see this article .

Answer 2

From the Spring Core documentation, paragraph 1.9.8 - Using @PostConstruct and @PreDestroy

Provided that the CommonAnnotationBeanPostProcessor is registered within the Spring ApplicationContext , a method carrying one of these annotations is invoked at the same point in the lifecycle as the corresponding Spring lifecycle interface method or explicitly declared callback method.

Declaring

<context:annotation-config/>

inside you applicationContext.xml file, implicitly register a CommonAnnotationBeanPostProcessor .

Otherwise, you need to manually register it, using ( docs )

<bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor" />

Answer 3

If you use java 9+ then add dependency javax.annotation:javax.annotation-api (or use java 8).

Or use spring-boot 2 if you using spring-boot 1.

Answer 4

Your Spring don't know about annotation's @PostContruct and @PreDestroy. Add this code in your applicationContext.xml

<bean class = "org.springframework.context.annotation.CommonAnnotationBeanPostProcessor"/>

Or implements InitializingBean,DisposableBean interfaces in your TenisCoach class.

Answer 5

Eclipse is unable to import @PostConstruct or @PreDestroy

This happens because of Java 9 and higher.

When using Java 9 and higher, javax.annotation has been removed from its default classpath. Solution

1. Download the javax.annotation-api-1.3.2.jar from

maven.org

2. Copy the JAR file to the lib folder of your project

Use the following steps to add it to your Java Build Path.

3. Right-click your project, select Properties

4. On left-hand side, click Java Build Path

5. In top-center of dialog, click Libraries

6. Click Classpath and then Click Add JARs ...

7. Navigate to the JAR file /lib/javax.annotation-api-1.3.2.jar

8. Click OK then click Apply and Close

Eclipse will perform a rebuild of your project and it will resolve the related build errors.