@Configuration and @bean annotations

These two annotations are usually used together.

The annotation class with @Configuration indicates that this class can use the Spring IoC container as the source for the bean definition. The @Bean annotation tells Spring that an annotation method with an @bean will return an object that should be registered as a Bean in the Spring application context.

import org.springframework.context.annotation.*;

@Configuration
public class HelloWorldConfig {
   @Bean 
   public HelloWorld helloWorld(a){
      return newHelloWorld(); }}Copy the code

The above code is equivalent to the configuration in beans.xml:

<beans>
   <bean id="helloWorld" class="com.sap.HelloWorld" />
</beans>
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This after @ Configuration modification of the role of the class, equivalent to a ClassPathXmlApplicationContext.

Here is the consumption code:

ApplicationContext ctx = 
			   new AnnotationConfigApplicationContext(HelloWorldConfig.class); 
			   HelloWorld helloWorld = ctx.getBean(HelloWorld.class);
			   helloWorld.setMessage("Hello World!");
			   helloWorld.getMessage();
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This HelloWorldConfig is dynamically enhanced by SpringCGLib:

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