Spring Boot 3.5 + Java 25 + Cloud Native 系列（四）：领域服务设计

spring:
  datasource:
    url: ${ORDER_DB_URL:jdbc:mysql://mysql:3306/shop_order?createDatabaseIfNotExist=true&useSSL=false&allowPublicKeyRetrieval=true}
    username: ${ORDER_DB_USERNAME:shop}
    password: ${ORDER_DB_PASSWORD:shop}
  jpa:
    hibernate:
      ddl-auto: validate  # 禁止 Hibernate 自动变更 schema
  flyway:
    enabled: true
    repair-on-migrate: true

-- V4__rename_player_id_to_buyer_id.sql
ALTER TABLE activity_participation CHANGE COLUMN player_id buyer_id VARCHAR(36);
ALTER TABLE activity_player_card CHANGE COLUMN player_id buyer_id VARCHAR(36);
ALTER TABLE activity_virtual_farm CHANGE COLUMN player_id buyer_id VARCHAR(36);

@Testcontainers
@SpringBootTest
class OrderServiceApplicationTests {
    @Container
    @ServiceConnection
    static MySQLContainer<?> mysql = new MySQLContainer<>("mysql:8.4");
}

@Entity
@Table(name = "shop_order")
public class ShopOrderEntity {
    @Id
    @Column(nullable = false, length = 36)
    private String id;  // UUID.randomUUID().toString()

    @Column(name = "order_no", nullable = false, unique = true, length = 32)
    private String orderNo;  // 对外展示用订单号

    @Column(name = "buyer_id", nullable = false, length = 64)
    private String buyerId;

    @Column(nullable = false, length = 32)
    private String status;  // OrderStatus.PENDING_PAYMENT 等字符串常量

    @Column(name = "total_amount", nullable = false, precision = 19, scale = 2)
    private BigDecimal totalAmount;

    // ... 其他字段
}

public interface ShopOrderRepository extends JpaRepository<ShopOrderEntity, String> {
    List<ShopOrderEntity> findByBuyerIdOrderByCreatedAtDesc(String buyerId);
    List<ShopOrderEntity> findBySellerIdOrderByCreatedAtDesc(String sellerId);
    Optional<ShopOrderEntity> findByPaymentTransactionId(String paymentTransactionId);
    Optional<ShopOrderEntity> findByOrderToken(String orderToken);
}

public record ApiResponse<T>(
        String traceId,
        String status,
        String message,
        T data) {

    public static <T> ApiResponse<T> success(T data) {
        return new ApiResponse<>(TraceIdExtractor.currentTraceId(), "SC_OK", "Success", data);
    }

    public static ApiResponse<Void> failure(BusinessErrorCode errorCode, String message) {
        return new ApiResponse<>(TraceIdExtractor.currentTraceId(), errorCode.getCode(), message, null);
    }
}

public enum CommonErrorCode implements BusinessErrorCode {
    VALIDATION_ERROR("SC_VALIDATION_ERROR", HttpStatus.BAD_REQUEST),
    TOO_MANY_REQUESTS("SC_TOO_MANY_REQUESTS", HttpStatus.TOO_MANY_REQUESTS),
    UNAUTHORIZED("SC_UNAUTHORIZED", HttpStatus.UNAUTHORIZED),
    FORBIDDEN("SC_FORBIDDEN", HttpStatus.FORBIDDEN),
    NOT_FOUND("SC_NOT_FOUND", HttpStatus.NOT_FOUND),
    DOWNSTREAM_ERROR("SC_DOWNSTREAM_ERROR", HttpStatus.BAD_GATEWAY),
    INTERNAL_ERROR("SC_INTERNAL_ERROR", HttpStatus.INTERNAL_SERVER_ERROR),
    INSUFFICIENT_BALANCE("SC_INSUFFICIENT_BALANCE", HttpStatus.BAD_REQUEST),
    COUPON_INVALID("SC_COUPON_INVALID", HttpStatus.BAD_REQUEST),
    COUPON_EXPIRED("SC_COUPON_EXPIRED", HttpStatus.BAD_REQUEST)
}

public final class OrderStatus {
    public static final String PENDING_PAYMENT = "PENDING_PAYMENT";
    public static final String PAID = "PAID";
    public static final String PROCESSING = "PROCESSING";
    public static final String SHIPPED = "SHIPPED";
    public static final String DELIVERED = "DELIVERED";
    public static final String COMPLETED = "COMPLETED";
    public static final String CANCELLED = "CANCELLED";
    public static final String REFUND_REQUESTED = "REFUND_REQUESTED";
    public static final String REFUND_APPROVED = "REFUND_APPROVED";
    public static final String REFUND_REJECTED = "REFUND_REJECTED";
}

public void markPaid(String paymentTransactionId) {
    assertStatus(OrderStatus.PENDING_PAYMENT, "pay");
    this.status = OrderStatus.PAID;
    this.paymentTransactionId = paymentTransactionId;
    this.paidAt = Instant.now();
}

@Entity
@Table(name = "compensation_task",
        indexes = @Index(name = "idx_comp_task_status_next",
                        columnList = "status, next_retry_at"))
public class CompensationTaskEntity {
    public enum Status { PENDING, SUCCEEDED, FAILED }

    @Id
    private String id;                      // UUID
    @Column(nullable = false)
    private String taskType;                // "ROLLBACK_INVENTORY", "CANCEL_RESERVATION"
    @Column(nullable = false)
    private String aggregateId;             // productId
    @Column(columnDefinition = "TEXT")
    private String payload;                 // quantity 等参数的 JSON
    @Enumerated(EnumType.STRING)
    private Status status;
    private int retryCount;
    private int maxRetries = 5;
    private Instant nextRetryAt;
    private String lastError;
}

@Scheduled(fixedDelayString = "${shop.compensation.retry-interval-ms:60000}")
@Transactional
public void retryPendingTasks() {
    List<CompensationTaskEntity> dueTasks = taskRepository.findDuePendingTasks(Instant.now());
    for (CompensationTaskEntity task : dueTasks) {
        try {
            executeTask(task);
            task.markSucceeded();
        } catch (Exception e) {
            task.recordFailure(e.getMessage());  // 指数退避: 4^retryCount * 30s
        }
        taskRepository.save(task);
    }
}

@RestController
@RequestMapping("/internal/marketplace/v1")
@Tag(name = "Marketplace Internal", description = "Internal API for BFF consumption")
public class MarketplaceInternalController {

    @Operation(summary = "List products by IDs",
               description = "Batch fetch products by their IDs")
    @ApiResponses({
        @ApiResponse(responseCode = "200", description = "Products found"),
        @ApiResponse(responseCode = "400", description = "Invalid request")
    })
    @PostMapping("/products/batch")
    public ApiResponse<List<ProductResponse>> listProductsByIds(
            @RequestBody @Valid ProductBatchRequest request) {
        // ...
    }
}