@PostConstruct and @PreDestroy Annotations in JSR-250 with Spring

In this chapter you will learn how to implement the @PostConstruct and @PreDestroy which work similar to init-method and destroy-method in bean configuration file (spring.xml) describe in earlier chapter or implement the InitializingBean and DisposableBean in your bean class.

To    use    @PostConstruct   and    @PreDestroy    you   have    to    register   the CommonAnnotationBeanPostProcessor   at   bean   configuration   or    specifying   the <context:annotation-config /> in the bean configuration file (spring.xml).

To define setup and teardown for a bean, we simply declare the with init-method and/or destroy-method parameters. The init-method attribute specifies a method that is to be called on the bean immediately upon instantiation. Similarly, destroy-method specifies a method that is called just before a bean is removed from the container.
Note:
The @PostConstruct and @PreDestroy annotation are not belong to Spring, it’s located in the J2ee library – common-annotations.jar
You can use @PostConstruct annotation as an alternate of initialization callback and @PreDestroy annotation as an alternate of destruction callback as explained in the below example.

Circle.java

package com.dineshonjava.sdnext.jsr.tutorial;

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

public class Circle
{ 
 private Point center;
 
 @Resource(name="pointB")
 public void setCenter(Point center) 
 {
     this.center = center;
 }
 
 public void draw() 
 {
System.out.println("Circle is drawn of center ("+center.getX()+", "+center.getY()+")");
 }
 
 @PostConstruct
 public void initializeCircle()
 {
     //populates the circle data cache upon initialization...  
     System.out.println("Init of Circle");
 }
 
 @PreDestroy
 public void destroyCircle()
 {
    //clears the circle related cache upon destruction..  
    System.out.println("Destroy of Circle");
 }
}

Point.java

package com.dineshonjava.sdnext.jsr.tutorial;

public class Point
{
 private int x;
 private int y;
 /**
  * @return the x
  */
 public int getX() {
  return x;
 }
 /**
  * @param x the x to set
  */
 public void setX(int x) {
  this.x = x;
 }
 /**
  * @return the y
  */
 public int getY() {
  return y;
 }
 /**
  * @param y the y to set
  */
 public void setY(int y) {
  this.y = y;
 }
}

DrawingApp.java

package com.dineshonjava.sdnext.jsr.tutorial;

import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author Dinesh
 *
 */
public class DrawingApp 
{
 /**
  * @param args
  */
 public static void main(String[] args) 
 {
AbstractApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
context.registerShutdownHook();
Circle circle = (Circle) context.getBean("circle");
circle.draw();
 }
}

By default, Spring will not aware of the @PostConstruct and @PreDestroy annotation. To enable it, you have to either register “CommonAnnotationBeanPostProcessor” or specify the <context:annotation-config /> in bean configuration file(spring.xml),

1. Using CommonAnnotationBeanPostProcessor

spring.xml

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans">
 
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Circle" id="circle"></bean>
  
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointA">
  <property name="x" value="0"></property>
  <property name="y" value="0"></property>
</bean>

<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointB">
  <property name="x" value="-20"></property>
  <property name="y" value="0"></property>
</bean>
  
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointC">
  <property name="x" value="20"></property>
  <property name="y" value="0"></property>
</bean> 

<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="center">
  <property name="x" value="10"></property>
  <property name="y" value="10"></property>
</bean>
  
<bean class="org.springframework.context.annotation.CommonAnnotationBeanPostProcessor"></bean>
</beans>

2. Using <context:annotation-config />

spring.xml

<beans xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p" xmlns:security="http://www.springframework.org/schema/security" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemalocation="http://www.springframework.org/schema/beans">
 
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Circle" id="circle"></bean>
  
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointA">
  <property name="x" value="0"></property>
  <property name="y" value="0"></property>
</bean>

<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointB">
  <property name="x" value="-20"></property>
  <property name="y" value="0"></property>
</bean>
  
<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="pointC">
  <property name="x" value="20"></property>
  <property name="y" value="0"></property>
</bean> 

<bean class="com.dineshonjava.sdnext.jsr.tutorial.Point" id="center">
  <property name="x" value="10"></property>
  <property name="y" value="10"></property>
</bean>
  
<context:annotation-config></context:annotation-config>
</beans>

Once you are done with creating source and bean configuration files, let us run the application. If everything is fine with your application, this will print the following message:

Output:
Jul 14, 2012 1:57:00 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@145d068: startup date [Sat Jul 14 01:57:00 IST 2012]; root of context hierarchy
Jul 14, 2012 1:57:00 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [spring.xml]
Jul 14, 2012 1:57:00 AM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@4e79f1: defining beans [circle,pointA,pointB,pointC,center,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy

Init of Circle
Circle is drawn of center (-20, 0)
Destroy of Circle

Spring Related Topics you may like

  1. Spring Interview Questions and Answers
  2. Spring AOP Interview Questions and Answers
  3. Spring MVC Interview Questions
  4. Spring Security Interview Questions and Answers
  5. Spring REST Interview Questions and Answers
  6. Spring Boot Interview Questions and Answers
  7. Spring Boot Microservices Interview Questions and Answers
  8. Dependency Injection (DI) in Spring
  9. Spring IoC Container
  10. What is Bean Factory in Spring
  11. ApplicationContext in Spring
  12. Bean Autowiring in Spring
  13. Spring Bean Scopes
  14. Create Custom Bean Scope in Spring Example
  15. Using ApplicationContextAware in Spring
  16. Spring Bean Life Cycle and Callbacks
  17. BeanPostProcessor in Spring
  18. BeanFactoryPostProcessor in Spring
  19. Annotations in Spring and Based Configuration
  20. Spring JSR-250 Annotations
  21. JSR 330 Annotations in Spring
  22. Spring @Component, @Repository, @Service and @Controller Stereotype Annotations
  23. Method injection with Spring using Lookup method property
  24. Spring AOP-Introduction to Aspect Oriented Programming
  25. @Aspect Annotation in Spring
  26. Spring AOP AspectJ @Before Annotation Advice Example
  27. Spring AOP Before Advice Example using XML Config
  28. Spring AOP AspectJ @After Annotation Advice Example
  29. Spring AOP After Advice Example using XML Config
  30. Spring AOP AspectJ @AfterReturning Annotation Advice Example
  31. Spring AOP After-Returning Advice Example using XML Config
  32. Spring AOP AspectJ @AfterThrowing Annotation Advice Example
  33. Spring AOP After Throwing Advice Example using XML Config
  34. Spring AOP AspectJ @Around Annotation Advice Example
  35. Spring AOP Around Advice Example using XML Config
  36. Spring AOP Proxies in Spring
  37. Spring AOP Transaction Management in Hibernate
  38. Spring Transaction Management
  39. Spring Declarative Transaction Management Example
  40. Spring AOP-Ordering of Aspects with Example
  41. Spring Security Java Based Configuration with Example
  42. Spring Security XML Namespace Configuration Example

Previous
Next