后台完成修复，初始化项目

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

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+package com.org.flashsalesystem.dto;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotNull;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+
+/**
+ * 订单数据传输对象
+ */
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class OrderDTO {
+
+    private Long id;
+    private Long userId;
+    private String username;
+    private Long productId;
+    private String productName;
+    private String productImageUrl;
+    private Integer quantity;
+    private BigDecimal totalPrice;
+    private Integer status;
+    private String statusDescription;
+    private Integer orderType;
+    private String orderTypeDescription;
+
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime createdAt;
+
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime updatedAt;
+
+    /**
+     * 创建订单DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class CreateDTO {
+        @NotNull(message = "商品ID不能为空")
+        private Long productId;
+
+        @Min(value = 1, message = "商品数量必须大于0")
+        private Integer quantity;
+
+        // 收货地址信息
+        private String receiverName;
+        private String receiverPhone;
+        private String receiverAddress;
+
+        // 备注
+        private String remark;
+    }
+
+    /**
+     * 订单查询DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class QueryDTO {
+        private Long userId;
+        private Integer status;
+        private Integer orderType;
+
+        @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 = "createdAt";
+        private String sortDirection = "desc";
+    }
+
+    /**
+     * 订单状态更新DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class StatusUpdateDTO {
+        @NotNull(message = "订单ID不能为空")
+        private Long orderId;
+
+        @NotNull(message = "订单状态不能为空")
+        private Integer status;
+
+        private String remark;
+    }
+
+    /**
+     * 批量订单操作DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class BatchOperationDTO {
+        @NotNull(message = "订单ID列表不能为空")
+        private java.util.List<Long> orderIds;
+
+        /**
+         * 操作类型：cancel-取消，pay-支付，ship-发货，complete-完成
+         */
+        @NotNull(message = "操作类型不能为空")
+        private String operation;
+
+        private String remark;
+    }
+
+    /**
+     * 订单统计DTO
+     */
+    @Data
+    @NoArgsConstructor
+    @AllArgsConstructor
+    public static class StatisticsDTO {
+        private Long totalOrders;
+        private Long pendingPaymentOrders;
+        private Long paidOrders;
+        private Long shippedOrders;
+        private Long completedOrders;
+        private Long cancelledOrders;
+        private BigDecimal totalAmount;
+        private BigDecimal todayAmount;
+        private Long flashSaleOrders;
+        private Long normalOrders;
+    }
+}