java

name	java
description	Build, review, and refactor Java backend services (Spring Boot). Use for tasks like REST API design, controllers/services/repositories, PostgreSQL persistence (JPA/MyBatis), migrations, configuration, security (Spring Security), observability, testing, performance tuning, and production hardening.

java

Use this skill for Java 后端服务（通常 Spring Boot）开发与评审。

Defaults (unless repo dictates otherwise)

• Framework: Spring Boot
• Build: Maven or Gradle (follow repo)
• API: REST + JSON, explicit DTOs
• DB: PostgreSQL, migrations via Flyway/Liquibase if present

Recommended structure

• controller/：HTTP layer（request/response DTO、参数校验、错误码映射）
• service/：业务编排与事务边界（domain logic orchestration）
• repository/：持久化（JPA repository / MyBatis mapper）
• domain/：领域模型（实体、值对象、聚合根）
• config/：配置（Web/Security/Serialization）
• integration/：第三方调用（HTTP clients, MQ）
• common/：通用工具（logging, id, time, error）
• test/：单测/集成测试

Workflow

1. Clarify contract

• Endpoint list, auth requirements, error codes, id format.
• Consistency with existing API versioning (/v1/...) and response envelope.

2. API design & validation

• Use DTOs; do not expose entities directly.
• Bean Validation (@Valid, @NotNull, etc.) for input.
• Standardize error responses (code/message/details).

3. Persistence & migrations

• Define schema and migration scripts (Flyway/Liquibase).
• Add indexes for query paths; ensure constraints align with requirements.
• Avoid N+1 queries (fetch joins, batch sizes, projections).

4. Transactions & consistency

• Define transaction boundaries at service layer (@Transactional).
• Keep read-only transactions where possible.
• Idempotency for write endpoints when needed.

5. Security

• Spring Security: authentication (JWT/session), authorization (roles/scopes).
• Secrets via env/config server; never commit credentials.
• Safe logging (no PII), rate limiting if required.

6. Observability

• Structured logs with correlation/request IDs.
• Metrics (latency, error rate, DB timings); tracing if available.

7. Testing

• Unit tests for services and domain logic.
• Integration tests for repositories and controllers (Testcontainers if used).
• Keep tests deterministic and fast.

Output expectations when making changes

• Keep diffs localized; avoid broad refactors unless requested.
• Update DTOs/migrations/tests together.
• Document new config/env vars and run steps.