XML Configuration with Java Annotations

In the last lesson, we removed all Java annotations from our application and used the appContext.xml file to define beans and inject the dependency. However, if we want to detect beans defined by the @Component annotation and inject the dependencies using @Autowired annotation while using XML context, we can do that too.

In large projects, declaring a lot of beans using the <bean> tag is cumbersome, so annotation-based dependency injection was introduced in Spring 2.52.52.5. This enabled automatic detection of beans having the @Component annotation. The <context:component-scan> tag is used to turn this feature on.

For the code example shown in this lesson, we use create a new package named lesson15 by copying lesson14 package from the previous lesson.

<context:component-scan> tag

Right now, we have declared three beans in appContext.xml. Suppose we want to declare the ContentBasedFilter and CollaborativeFilter beans using the @Component annotation instead of defining them using the <bean> tag in appContext.xml.

Here’s the ContentBasedFilter class: