# CampusIdleItemTradingPlatform — server

## Build & dev

```bash
./mvnw spring-boot:run          # start dev server on :8080
./mvnw compile                  # compile
./mvnw test                     # run tests (none exist yet)
```

## Prerequisites

- **Java 17+**, Maven wrapper included (`./mvnw`)
- **MySQL** at `localhost:3306` — execute `src/main/resources/init.sql` to init DB
  - DB: `campus_idle_item_trading_platform`, user: `root` / `root`
- App uses **MySQL HikariCP** connection pool (max 20)

## Architecture

- **Package**: `com.campus.trade.*` — **not** the old `space.anyi...` namespace
- **Entrypoint**: `com.campus.trade.ServerApplication` (`scanBasePackages = "com.campus.trade"`)
- **Layered**: `controller → service[/admin] → mapper → entity`, with DTO/VO at boundaries
- **Auth**: Session-based (`HttpSession`). `AuthInterceptor` guards all paths; whitelist for `/auth/register`, `/auth/login`, `/items(/**) GET`, `/upload/`, `/v3/api-docs`, `/swagger-ui`
  - Session attributes: `userId` (Long), `role` (String)
  - Controller reads user via `session.getAttribute("userId")`
- **Context-path**: `/` (plain), not `/api`
- **OpenAPI docs**: `http://localhost:8080/swagger-ui.html` / `/v3/api-docs`
- **Password**: MD5 via `org.springframework.util.DigestUtils`
- **File upload**: to `./upload/` (created at runtime), served at `/upload/`
  - Multipart requests: `consumes = MediaType.MULTIPART_FORM_DATA_VALUE`
- **Pagination**: PageHelper (`PageHelper.startPage(pageNum, pageSize)` in Service layer)

## Coding conventions

- **OpenAPI annotations** on every controller API — `@Operation`, `@Parameter`, `@Schema` from `io.swagger.v3.oas.annotations`; class-level `@Tag`
- **DTO / VO** for params/responses — never expose entities in controller signatures
- **Business logic in Service layer** — Controller only delegates; Service methods with `@Transactional`
- **Entity field comments** — every field gets a `// inline comment`
- **Business logic comments** — inline comments at key steps explaining the approach
- **MyBatis XML** — `#{}` parameter binding; `resultType` uses type-alias (`com.campus.trade.entity`)
- **Status enums** as plain strings: e.g. `"PENDING"`, `"ON_SALE"`, `"AUTHENTICATED"`, `"ENABLED"`
- **Order status machine** in `OrderStatusMachine` validates all transitions