Spring annotation-config Example
October 24, 2021
annotation-config is configured in Spring XML configuration. The annotation-config activates various annotations to be detected in bean classes. It is configured in XML configuration as following.
<context:annotation-config/>
annotation-config activates following annotations in bean classes.
1. Spring
@Required and @Autowired annotations.
2. JSR 250
@PostConstruct, @PreDestroy and @Resource annotations.
3. JAX-WS
@WebServiceRef annotation.
4. EJB 3
@EJB annotation.
5. JPA
@PersistenceContext and @PersistenceUnit annotations.
Note: The
annotation-config element does not activate Spring @Transactional or EJB 3 @TransactionAttribute annotation. To activate these annotations, we need to configure <tx:annotation-driven> element.
To activate Spring stereotype annotations such as
@Component, @Service, @Repository and @Controller annotations, we need to configure component-scan element in XML configurations or @ComponentScan annotation in JavaConfig.
Example
In our demo application, we are using@PostConstruct, @PreDestroy and @Resource annotations. We are using XML configurations in our demo application and to activate those annotations in our bean classes, we just have to configure annotation-config element in XML configuration.
spring-app.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<context:annotation-config />
<bean id="book" class="com.concretepage.Book">
<constructor-arg type="java.lang.String" value="Ramayan" />
</bean>
<bean id="location" class="com.concretepage.LocationService" />
<bean id="city" class="com.concretepage.City">
<property name="cityName" value="Ayodhya" />
</bean>
</beans>
package com.concretepage;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
public class Book {
private String bookName;
public Book(String bookName) {
this.bookName = bookName;
}
@PostConstruct
public void springPostConstruct() {
System.out.println("---Do initialization task---");
if (bookName != null) {
System.out.println("bookName property initialized with the value:" + bookName);
}
}
public String getBookName() {
return bookName;
}
@PreDestroy
public void springPreDestroy() {
System.out.println("---Release resources or perform destruction task---");
}
}
package com.concretepage;
public class City {
private String cityName;
public String getCityName() {
return cityName;
}
public void setCityName(String cityName) {
this.cityName = cityName;
}
}
package com.concretepage;
import javax.annotation.Resource;
public class LocationService {
@Resource(name="city")
private City objCity;
public City getObjCity() {
return objCity;
}
}
package com.concretepage;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class SpringDemo {
public static void main(String... args) {
AbstractApplicationContext context = new ClassPathXmlApplicationContext("spring-app.xml");
LocationService st = (LocationService) context.getBean("location");
String city = st.getObjCity().getCityName();
System.out.println(city);
Book book = (Book) context.getBean("book");
System.out.println(book.getBookName());
context.registerShutdownHook();
context.close();
}
}
---Do initialization task--- bookName property initialized with the value:Ramayan Ayodhya Ramayan ---Release resources or perform destruction task---
