--- name: springboot-patterns description: Spring Boot 架构模式、REST API 设计、分层服务、数据访问、缓存、异步处理和日志记录。适用于 Java Spring Boot 后端开发工作。 --- # Spring Boot 开发模式 (Spring Boot Development Patterns) 适用于可扩展、生产级服务的 Spring Boot 架构与 API 模式。 ## REST API 结构 ```java @RestController @RequestMapping("/api/markets") @Validated class MarketController { private final MarketService marketService; MarketController(MarketService marketService) { this.marketService = marketService; } @GetMapping ResponseEntity> list( @RequestParam(defaultValue = "0") int page, @RequestParam(defaultValue = "20") int size) { Page markets = marketService.list(PageRequest.of(page, size)); return ResponseEntity.ok(markets.map(MarketResponse::from)); } @PostMapping ResponseEntity create(@Valid @RequestBody CreateMarketRequest request) { Market market = marketService.create(request); return ResponseEntity.status(HttpStatus.CREATED).body(MarketResponse.from(market)); } } ``` ## 仓储模式 (Repository Pattern - Spring Data JPA) ```java public interface MarketRepository extends JpaRepository { @Query("select m from MarketEntity m where m.status = :status order by m.volume desc") List findActive(@Param("status") MarketStatus status, Pageable pageable); } ``` ## 带事务的服务层 (Service Layer with Transactions) ```java @Service public class MarketService { private final MarketRepository repo; public MarketService(MarketRepository repo) { this.repo = repo; } @Transactional public Market create(CreateMarketRequest request) { MarketEntity entity = MarketEntity.from(request); MarketEntity saved = repo.save(entity); return Market.from(saved); } } ``` ## DTO 与校验 (DTOs and Validation) ```java public record CreateMarketRequest( @NotBlank @Size(max = 200) String name, @NotBlank @Size(max = 2000) String description, @NotNull @FutureOrPresent Instant endDate, @NotEmpty List<@NotBlank String> categories) {} public record MarketResponse(Long id, String name, MarketStatus status) { static MarketResponse from(Market market) { return new MarketResponse(market.id(), market.name(), market.status()); } } ``` ## 异常处理 (Exception Handling) ```java @ControllerAdvice class GlobalExceptionHandler { @ExceptionHandler(MethodArgumentNotValidException.class) ResponseEntity handleValidation(MethodArgumentNotValidException ex) { String message = ex.getBindingResult().getFieldErrors().stream() .map(e -> e.getField() + ": " + e.getDefaultMessage()) .collect(Collectors.joining(", ")); return ResponseEntity.badRequest().body(ApiError.validation(message)); } @ExceptionHandler(AccessDeniedException.class) ResponseEntity handleAccessDenied() { return ResponseEntity.status(HttpStatus.FORBIDDEN).body(ApiError.of("Forbidden")); } @ExceptionHandler(Exception.class) ResponseEntity handleGeneric(Exception ex) { // 记录带有堆栈跟踪的非预期错误 return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR) .body(ApiError.of("Internal server error")); } } ``` ## 缓存 (Caching) 需要在配置类上添加 `@EnableCaching`。 ```java @Service public class MarketCacheService { private final MarketRepository repo; public MarketCacheService(MarketRepository repo) { this.repo = repo; } @Cacheable(value = "market", key = "#id") public Market getById(Long id) { return repo.findById(id) .map(Market::from) .orElseThrow(() -> new EntityNotFoundException("Market not found")); } @CacheEvict(value = "market", key = "#id") public void evict(Long id) {} } ``` ## 异步处理 (Async Processing) 需要在配置类上添加 `@EnableAsync`。 ```java @Service public class NotificationService { @Async public CompletableFuture sendAsync(Notification notification) { // 发送 邮件/短信 return CompletableFuture.completedFuture(null); } } ``` ## 日志记录 (Logging - SLF4J) ```java @Service public class ReportService { private static final Logger log = LoggerFactory.getLogger(ReportService.class); public Report generate(Long marketId) { log.info("generate_report marketId={}", marketId); try { // 业务逻辑 } catch (Exception ex) { log.error("generate_report_failed marketId={}", marketId, ex); throw ex; } return new Report(); } } ``` ## 中间件 / 过滤器 (Middleware / Filters) ```java @Component public class RequestLoggingFilter extends OncePerRequestFilter { private static final Logger log = LoggerFactory.getLogger(RequestLoggingFilter.class); @Override protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { long start = System.currentTimeMillis(); try { filterChain.doFilter(request, response); } finally { long duration = System.currentTimeMillis() - start; log.info("req method={} uri={} status={} durationMs={}", request.getMethod(), request.getRequestURI(), response.getStatus(), duration); } } } ``` ## 分页与排序 (Pagination and Sorting) ```java PageRequest page = PageRequest.of(pageNumber, pageSize, Sort.by("createdAt").descending()); Page results = marketService.list(page); ``` ## 容错性外部调用 (Error-Resilient External Calls) ```java public T withRetry(Supplier supplier, int maxRetries) { int attempts = 0; while (true) { try { return supplier.get(); } catch (Exception ex) { attempts++; if (attempts >= maxRetries) { throw ex; } try { Thread.sleep((long) Math.pow(2, attempts) * 100L); } catch (InterruptedException ie) { Thread.currentThread().interrupt(); throw ex; } } } } ``` ## 限流 (Filter + Bucket4j) **安全注意事项**：`X-Forwarded-For` 请求头默认是不可信的，因为客户端可以伪造它。 仅在以下情况下使用转发请求头： 1. 你的应用位于受信任的反向代理（nginx、AWS ALB 等）之后 2. 你已将 `ForwardedHeaderFilter` 注册为 Bean 3. 你在 application 属性中配置了 `server.forward-headers-strategy=NATIVE` 或 `FRAMEWORK` 4. 你的代理配置为覆盖（而非追加）`X-Forwarded-For` 请求头 当 `ForwardedHeaderFilter` 配置正确时，`request.getRemoteAddr()` 将自动从转发头中返回正确的客户端 IP。如果没有此配置，请直接使用 `request.getRemoteAddr()`——它返回直接连接的 IP，这是唯一可信的值。 ```java @Component public class RateLimitFilter extends OncePerRequestFilter { private final Map buckets = new ConcurrentHashMap<>(); /* * 安全提示：此过滤器使用 request.getRemoteAddr() 来识别用于限流的客户端。 * * 如果你的应用位于反向代理（nginx、AWS ALB 等）之后，你必须配置 Spring * 正确处理转发头，以便准确检测客户端 IP： * * 1. 在 application.properties/yaml 中设置 server.forward-headers-strategy=NATIVE * (适用于云平台) 或 FRAMEWORK * 2. 如果使用 FRAMEWORK 策略，请注册 ForwardedHeaderFilter： * * @Bean * ForwardedHeaderFilter forwardedHeaderFilter() { * return new ForwardedHeaderFilter(); * } * * 3. 确保你的代理覆盖（而不是追加）X-Forwarded-For 请求头以防止伪造 * 4. 为你的容器配置 server.tomcat.remoteip.trusted-proxies 或等效配置 * * 如果没有这些配置，request.getRemoteAddr() 将返回代理服务器的 IP，而非客户端 IP。 * 不要直接读取 X-Forwarded-For —— 在没有受信任代理处理的情况下，它是极易伪造的。 */ @Override protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { // 使用 getRemoteAddr()，它在配置了 ForwardedHeaderFilter 时返回正确的客户端 IP， // 否则返回直接连接的 IP。在没有正确代理配置的情况下，切勿直接信任 X-Forwarded-For 头。 String clientIp = request.getRemoteAddr(); Bucket bucket = buckets.computeIfAbsent(clientIp, k -> Bucket.builder() .addLimit(Bandwidth.classic(100, Refill.greedy(100, Duration.ofMinutes(1)))) .build()); if (bucket.tryConsume(1)) { filterChain.doFilter(request, response); } else { response.setStatus(HttpStatus.TOO_MANY_REQUESTS.value()); } } } ``` ## 后台任务 (Background Jobs) 使用 Spring 的 `@Scheduled` 或集成队列（如 Kafka、SQS、RabbitMQ）。保持处理程序具有幂等性和可观测性。 ## 可观测性 (Observability) - 通过 Logback encoder 实现结构化日志（JSON） - 指标（Metrics）：Micrometer + Prometheus/OTel - 链路追踪（Tracing）：使用 OpenTelemetry 或 Brave 后端的 Micrometer Tracing ## 生产环境默认实践 (Production Defaults) - 优先使用构造函数注入，避免字段注入 - 为 RFC 7807 错误启用 `spring.mvc.problemdetails.enabled=true` (Spring Boot 3+) - 根据工作负载配置 HikariCP 连接池大小并设置超时 - 为查询使用 `@Transactional(readOnly = true)` - 通过 `@NonNull` 和 `Optional` 在适当时强制执行空安全（null-safety） **切记**：保持控制器（Controller）薄、服务（Service）专注、仓储（Repository）简单，并集中处理错误。针对可维护性和可测试性进行优化。