Kotlin 与 Spring Boot 开发指引

作者原文

Get best practices for developing applications with Spring Boot and Kotlin.

SkillPi 解读

能完成的任务

Kotlin 与 Spring Boot 开发指引

适合谁

请按作者原文中的适用场景判断。

输入和输出

以作者完整文档为准；本站未运行验证产物。

软件、账号及付费要求

使用前按完整文档确认软件、账号、费用及权限；由宿主核对并授权实际文件读写和外部服务。文档引用域名（非运行白名单）：未列出 HTTP(S) 域名。

限制与区别

原文中的功能、版本状态和效果描述属于作者陈述；中文为对应翻译。仅核对固定版本及静态附件证据，不保证运行效果、外部服务或兼容性。

实测状态

未测试

安全评级与访问范围

caution · 静态证据核验，不代表运行安全保证。

使用前按完整文档确认软件、账号、费用及权限；由宿主核对并授权实际文件读写和外部服务。文档引用域名（非运行白名单）：未列出 HTTP(S) 域名。

使用前请由宿主核对并授权实际文件读写、外部服务和联网目的地；本站的核验不会授予任何运行权限。

原始 SKILL.md

---
name: kotlin-springboot
description: 'Get best practices for developing applications with Spring Boot and Kotlin.'
---

# Spring Boot with Kotlin Best Practices

Your goal is to help me write high-quality, idiomatic Spring Boot applications using Kotlin.

## Project Setup & Structure

- **Build Tool:** Use Maven (`pom.xml`) or Gradle (`build.gradle`) with the Kotlin plugins (`kotlin-maven-plugin` or `org.jetbrains.kotlin.jvm`).
- **Kotlin Plugins:** For JPA, enable the `kotlin-jpa` plugin to automatically make entity classes `open` without boilerplate.
- **Starters:** Use Spring Boot starters (e.g., `spring-boot-starter-web`, `spring-boot-starter-data-jpa`) as usual.
- **Package Structure:** Organize code by feature/domain (e.g., `com.example.app.order`, `com.example.app.user`) rather than by layer.

## Dependency Injection & Components

- **Primary Constructors:** Always use the primary constructor for required dependency injection. It's the most idiomatic and concise approach in Kotlin.
- **Immutability:** Declare dependencies as `private val` in the primary constructor. Prefer `val` over `var` everywhere to promote immutability.
- **Component Stereotypes:** Use `@Service`, `@Repository`, and `@RestController` annotations just as you would in Java.

## Configuration

- **Externalized Configuration:** Use `application.yml` for its readability and hierarchical structure.
- **Type-Safe Properties:** Use `@ConfigurationProperties` with `data class` to create immutable, type-safe configuration objects.
- **Profiles:** Use Spring Profiles (`application-dev.yml`, `application-prod.yml`) to manage environment-specific configurations.
- **Secrets Management:** Never hardcode secrets. Use environment variables or a dedicated secret management tool like HashiCorp Vault or AWS Secrets Manager.

## Web Layer (Controllers)

- **RESTful APIs:** Design clear and consistent RESTful endpoints.
- **Data Classes for DTOs:** Use Kotlin `data class` for all DTOs. This provides `equals()`, `hashCode()`, `toString()`, and `copy()` for free and promotes immutability.
- **Validation:** Use Java Bean Validation (JSR 380) with annotations (`@Valid`, `@NotNull`, `@Size`) on your DTO data classes.
- **Error Handling:** Implement a global exception handler using `@ControllerAdvice` and `@ExceptionHandler` for consistent error responses.

## Service Layer

- **Business Logic:** Encapsulate business logic within `@Service` classes.
- **Statelessness:** Services should be stateless.
- **Transaction Management:** Use `@Transactional` on service methods. In Kotlin, this can be applied to class or function level.

## Data Layer (Repositories)

- **JPA Entities:** Define entities as classes. Remember they must be `open`. It's highly recommended to use the `kotlin-jpa` compiler plugin to handle this automatically.
- **Null Safety:** Leverage Kotlin's null-safety (`?`) to clearly define which entity fields are optional or required at the type level.
- **Spring Data JPA:** Use Spring Data JPA repositories by extending `JpaRepository` or `CrudRepository`.
- **Coroutines:** For reactive applications, leverage Spring Boot's support for Kotlin Coroutines in the data layer.

## Logging

- **Companion Object Logger:** The idiomatic way to declare a logger is in a companion object.
  ```kotlin
  companion object {
      private val logger = LoggerFactory.getLogger(MyClass::class.java)
  }
  ```
- **Parameterized Logging:** Use parameterized messages (`logger.info("Processing user {}...", userId)`) for performance and clarity.

## Testing

- **JUnit 5:** JUnit 5 is the default and works seamlessly with Kotlin.
- **Idiomatic Testing Libraries:** For more fluent and idiomatic tests, consider using **Kotest** for assertions and **MockK** for mocking. They are designed for Kotlin and offer a more expressive syntax.
- **Test Slices:** Use test slice annotations like `@WebMvcTest` or `@DataJpaTest` to test specific parts of the application.
- **Testcontainers:** Use Testcontainers for reliable integration tests with real databases, message brokers, etc.

## Coroutines & Asynchronous Programming

- **`suspend` functions:** For non-blocking asynchronous code, use `suspend` functions in your controllers and services. Spring Boot has excellent support for coroutines.
- **Structured Concurrency:** Use `coroutineScope` or `supervisorScope` to manage the lifecycle of coroutines.

版权与许可声明

MIT License

Copyright GitHub, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.