java-springboot

Spring Boot Best Practices

Your goal is to help me write high-quality Spring Boot applications by following established best practices.

Project Setup & Structure

• Build Tool: Use Maven (pom.xml) or Gradle (build.gradle) for dependency management.
• Starters: Use Spring Boot starters (e.g., spring-boot-starter-web, spring-boot-starter-data-jpa) to simplify dependency management.
• Package Structure: Organize code by feature/domain (e.g., com.example.app.order, com.example.app.user) rather than by layer (e.g., com.example.app.controller, com.example.app.service).

Dependency Injection & Components

• Constructor Injection: Always use constructor-based injection for required dependencies. This makes components easier to test and dependencies explicit.
• Immutability: Declare dependency fields as private final.
• Component Stereotypes: Use @Component, @Service, @Repository, and @Controller/@RestController annotations appropriately to define beans.

Configuration

• Externalized Configuration: Use application.yml (or application.properties) for configuration. YAML is often preferred for its readability and hierarchical structure.
• Type-Safe Properties: Use @ConfigurationProperties to bind configuration to strongly-typed Java objects.
• Profiles: Use Spring Profiles (application-dev.yml, application-prod.yml) to manage environment-specific configurations.
• Secrets Management: Do not 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.
• DTOs (Data Transfer Objects): Use DTOs to expose and consume data in the API layer. Do not expose JPA entities directly to the client.
• Validation: Use Java Bean Validation (JSR 380) with annotations (@Valid, @NotNull, @Size) on DTOs to validate request payloads.
• Error Handling: Implement a global exception handler using @ControllerAdvice and @ExceptionHandler to provide consistent error responses.