In Spring, InitializingBean
and DisposableBean
are two marker interfaces, a useful way for Spring to perform certain actions upon bean initialization and destruction.
For bean implemented InitializingBean
, it will run after PropertiesSet()
after all bean properties have been set.
For bean implemented DisposableBean
, it will rundestroy()
after Spring container is released the bean.
Example
Here’s an example to show you how to use InitializingBean
and DisposableBean
. A CustomerService
bean to implement both InitializingBean
and DisposableBean interface, and has a message property.
package com.mkyong.customer.services;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
public class CustomerService implements InitializingBean, DisposableBean{
String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public void afterPropertiesSet() throws Exception {
System.out.println("Init method after properties are set : " + message);
}
public void destroy() throws Exception {
System.out.println("Spring Container is destroy! Customer clean up");
}
}
File : Spring-Customer.xml
<?xml version="1.0"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="customerService" class="com.mkyong.customer.services.CustomerService">
<property name="message" value="i'm property message" />
</bean>
</beans>
Run it
package com.mkyong.common;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.mkyong.customer.services.CustomerService;
public class App {
public static void main( String[] args ) {
ConfigurableApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"Spring-Customer.xml"});
CustomerService cust = (CustomerService)context.getBean("customerService");
System.out.println(cust);
context.close();
}
}
The ConfigurableApplicationContext.close()
will close the application context, releasing all resources and destroying all cached singleton beans. It’s use for destroy()
method demo purpose only :)
Output
Init method after properties are set : im property message
com.mkyong.customer.services.CustomerService@47393f
...
INFO: Destroying singletons in org.springframework.beans.factory.
support.DefaultListableBeanFactory@77158a:
defining beans [customerService]; root of factory hierarchy
Spring Container is destroy! Customer clean up
The afterPropertiesSet()
method is called, after the message property is set; while the destroy()
method is call after the context.close()
;
Thoughts…
I would not recommend to use InitializingBean and DisposableBean interface, because it will tight coupled your code to Spring. A better approach should be specifying the init-method and destroy-method attributes in your bean configuration file.