后台完成修复，初始化项目

src/main/java/com/org/flashsalesystem/dto/FlashSaleDTO.java

@@ -0,0 +1,164 @@
+package com.org.flashsalesystem.dto;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.validation.constraints.DecimalMin;
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+
+/**
+ * 秒杀活动数据传输对象
+ */
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class FlashSaleDTO {
+
+    private Long id;
+    private Long productId;
+    private String productName;
+    private String productImageUrl;
+    private BigDecimal originalPrice;
+    private BigDecimal flashPrice;
+    private Integer flashStock;
+    private Integer remainingStock;
+
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime startTime;
+
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime endTime;
+
+    private Integer status;
+
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime createdAt;
+
+    // 活动状态描述
+    private String statusDescription;
+    // 是否可以参与秒杀
+    private Boolean canParticipate;
+    // 距离开始时间（毫秒）
+    private Long timeToStart;
+    // 距离结束时间（毫秒）
+    private Long timeToEnd;
+
+    /**
+     * 创建秒杀活动DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class CreateDTO {
+        @NotNull(message = "商品ID不能为空")
+        private Long productId;
+
+        @NotNull(message = "秒杀价格不能为空")
+        @DecimalMin(value = "0.01", message = "秒杀价格必须大于0")
+        private BigDecimal flashPrice;
+
+        @Min(value = 1, message = "秒杀库存必须大于0")
+        private Integer flashStock;
+
+        @NotNull(message = "开始时间不能为空")
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime startTime;
+
+        @NotNull(message = "结束时间不能为空")
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime endTime;
+    }
+
+    /**
+     * 更新秒杀活动DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class UpdateDTO {
+        @DecimalMin(value = "0.01", message = "秒杀价格必须大于0")
+        private BigDecimal flashPrice;
+
+        @Min(value = 1, message = "秒杀库存必须大于0")
+        private Integer flashStock;
+
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime startTime;
+
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime endTime;
+
+        @Min(value = 1, message = "状态值无效")
+        @Max(value = 3, message = "状态值无效")
+        private Integer status;
+    }
+
+    /**
+     * 秒杀参与DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class ParticipateDTO {
+        @NotNull(message = "秒杀活动ID不能为空")
+        private Long flashSaleId;
+
+        @Min(value = 1, message = "购买数量必须大于0")
+        private Integer quantity = 1;
+
+        // 用户地址信息（可选）
+        private String address;
+        private String phone;
+    }
+
+    /**
+     * 秒杀查询DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class QueryDTO {
+        private Integer status; // 活动状态
+        private Long productId; // 商品ID
+
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime startTime;
+
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime endTime;
+        private Integer page = 0;
+        private Integer size = 10;
+        private String sortBy = "startTime";
+        private String sortDirection = "asc";
+    }
+
+    /**
+     * 秒杀结果DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class ResultDTO {
+        private Boolean success;
+        private String message;
+        private Long orderId;
+        private Long flashSaleId;
+        private Long productId;
+        private String productName;
+        private Integer quantity;
+        private BigDecimal totalPrice;
+
+        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+        private LocalDateTime orderTime;
+
+        // 排队信息（如果需要排队）
+        private Integer queuePosition;
+        private Long estimatedWaitTime;
+    }
+}