@ComponentScan with arguments

[Jan Kaczmarek]

Hello!
I just added spring to my app and Im not sure how to use @ComponentScan proper. I know that if I will leave it no-args it will just scan current package and sub-packages. I can add args-and pick specific package but how it will ends if I would use @ComponentScan("java") like this :


It will scan my whole app? Or it wont scan anything?
Thanks in advance for an answer!

[Campbell Ritchie]

Moved to our Spring forum.

[Stephan van Hulst]

What this will do is register all beans in the "java" package and sub-packages and make them available for you to inject in your application.

I hypothesize that it will make your application a lot slower and it will also be completely pointless because there are no services in the packages I mentioned that use annotations to inject the discovered beans.

Why would you want to do this?

[Jan Kaczmarek]

Stephan van Hulst wrote:What this will do is register all beans in the "java" package and sub-packages and make them available for you to inject in your application.

I hypothesize that it will make your application a lot slower and it will also be completely pointless because there are no services in the packages I mentioned that use annotations to inject the discovered beans.

Why would you want to do this?

Im looking for good place to put this Config class with @ComponentScan annotation. So my solution is to move all packages (service, data, model, presentation) to new, big package like "student-management-system" and put @ComponentScan("student-management-system") ? Because I do not see any other solution for the scan to work.

[Stephan van Hulst]

Okay, that's better than using java as your base package.

But still, why don't you just put your Config class in the student-management-system package?

[Tim Holloway]

The whole purpose of ComponentScan is to limit what packages are scanned for the presence of eligible components rather than simply enumerating - at immense cost - every class in the application classpath. You should always strive to limit components to narrow sets of package trees so that the application will configure faster and waste fewer computing resources.

[Himai Minh]

Hi, Jan,
Is your Runner class annotated with @SpringBootApplication?
Since your Runner class is at the root directory and I assume it is annotated with @SpringBootApplication, @ComponentScan can be omitted.

@SpringBootApplication has meta-annotated with @ComponentScan.
It will scan the current root directory and all sub packages.

[Rob Spoor]

Stephan van Hulst wrote:But still, why don't you just put your Config class in the student-management-system package?

Because package names cannot contain dashes