Spring Boot Learning Cockpit

Use one workspace to understand MVC, validation, security, AOP, and application events.

This homepage is now a guided study cockpit. Instead of only linking to pages, it explains the request path, suggests experiment sequences, and lets you call real endpoints to observe how the demo behaves.

Core labs4

Major layers6

Interactive pages4

Tested backend paths2+

Recommended study order

1. Learn endpoint binding

Hit the live API explorer below and compare query, path, header, cookie, and JSON body patterns.

2. Study users and validation

Open the user lab to inspect CRUD, duplicate email handling, and aggregate stats.

3. Watch cross-cutting behavior

Move to AOP and events to see timing, rate limiting, and listener history.

How one request travels through the demo

BrowserForm submit or fetch call starts the request.

SecurityJWT demo routes decide whether the request is public or protected.

ControllerSpring binds params, body, headers, and cookies into method arguments.

ServiceBusiness rules run, such as duplicate email checks or stats calculation.

AOP / EventsCross-cutting timing or event listeners react without cluttering core logic.

ResponseStructured JSON or HTML returns to the page and becomes visible feedback.

What to practice in each area

User management Create a user, trigger duplicate email protection, search records, and compare stats before and after changes.

MVC parameter binding Use `/learn` routes to compare `@RequestParam`, `@PathVariable`, `@RequestBody`, `@RequestHeader`, and `@CookieValue`.

AOP tracing Trigger `/api/users` and `/api/users/stats`, then inspect `/aop/aop/stats` to see which methods were counted.

Application events Publish LOGIN or CREATED events and refresh event history to understand publisher-listener decoupling.

Code Reading Map

Files worth reading next

UserController -> UserService Shows validation, CRUD orchestration, search, and stats aggregation.

LearningSecurityConfig + LearningJwtFilter Explains why most labs stay public while `/api/secure/**` stays protected.

PerformanceAspect + UserEventPublisher + UserEventListener Shows the two cleanest examples of cross-cutting and event-driven behavior.

Live Explorer

Call real endpoints without leaving the page

Use these controls to inspect real JSON responses while you read the code. This makes the project easier to connect to concrete behavior.

Publish demo event

User id

User name

Endpoint output

Select an experiment above to load live output.

Experiment 1

Trace validation

Open the user lab, create a user, then repeat with the same email. Compare the frontend error with `DuplicateEmailException` and the global exception handler.

UserController UserService GlobalExceptionHandler

Experiment 2

Trace AOP timing

Load users and stats several times, then call `/aop/aop/stats`. Watch how controller and service methods accumulate timing and call count data.

PerformanceAspect @Around Cross-cutting

Experiment 3

Trace event decoupling

Publish CREATED and LOGIN events, then reload event history. This shows how the request can finish while listeners keep handling side effects.

Publisher Listener @Async