jiahong
375 lines
14 KiB
Java
375 lines
14 KiB
Java
/*
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* 自然写教学资源管理与内容分发系统软件 V1.0
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* service/DotCodeService.java - 点阵码生成引擎服务
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*/
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package com.writech.resource.service;
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import java.util.*;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.logging.Logger;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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/**
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* 点阵码生成引擎服务
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*
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* 负责点阵码资源的生成、分配和管理。
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* 点阵码是自然写系统的核心技术，每个点阵码对应一个唯一的
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* 页面/区域标识，配合点阵笔可精确定位书写位置。
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*
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* 功能：
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* - 点阵码ID全局唯一分配（防冲突）
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* - 点阵码图案生成（OGP编码）
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* - 点阵码与页面/课件的绑定关系管理
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* - 批量生成点阵码资源包
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* - 点阵码PDF合成（叠加到字帖/试卷模板上）
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*/
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public class DotCodeService {
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private static final Logger logger =
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Logger.getLogger(DotCodeService.class.getName());
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// ============================================================
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// 点阵码常量与配置
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// ============================================================
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/** OGP点阵码编码参数 */
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private static final int DOT_GRID_SIZE = 6; // 每组点阵6x6
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private static final double DOT_SPACING_MM = 0.3; // 点间距0.3mm
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private static final double DOT_OFFSET_MM = 0.1; // 点偏移量0.1mm
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private static final int DOTS_PER_PAGE = 10000; // 每页约10000个点
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/** 点阵码ID分配范围 */
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private static final long ID_RANGE_START = 1_000_000_000L;
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private static final long ID_RANGE_END = 9_999_999_999L;
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/** 当前已分配的最大ID（原子操作保证线程安全） */
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private long currentMaxId = ID_RANGE_START;
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/** 点阵码-页面绑定关系缓存 */
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private final Map<Long, DotCodeBinding> bindingCache = new ConcurrentHashMap<>();
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// ============================================================
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// 数据模型
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// ============================================================
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/** 点阵码绑定关系 */
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public static class DotCodeBinding {
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private long dotCodeId; // 点阵码ID
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private String resourceId; // 绑定的资源ID
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private int pageIndex; // 页面序号
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private String areaType; // 区域类型（full_page/answer_area/title_area）
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private double areaX; // 区域起始X坐标（mm）
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private double areaY; // 区域起始Y坐标（mm）
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private double areaWidth; // 区域宽度（mm）
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private double areaHeight; // 区域高度（mm）
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private Date createdAt;
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public DotCodeBinding() {}
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public DotCodeBinding(long dotCodeId, String resourceId, int pageIndex) {
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this.dotCodeId = dotCodeId;
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this.resourceId = resourceId;
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this.pageIndex = pageIndex;
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this.createdAt = new Date();
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}
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public long getDotCodeId() { return dotCodeId; }
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public void setDotCodeId(long id) { this.dotCodeId = id; }
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public String getResourceId() { return resourceId; }
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public void setResourceId(String rid) { this.resourceId = rid; }
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public int getPageIndex() { return pageIndex; }
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public void setPageIndex(int idx) { this.pageIndex = idx; }
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public String getAreaType() { return areaType; }
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public void setAreaType(String type) { this.areaType = type; }
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public double getAreaX() { return areaX; }
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public double getAreaY() { return areaY; }
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public double getAreaWidth() { return areaWidth; }
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public double getAreaHeight() { return areaHeight; }
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}
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/** 点阵码生成请求 */
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public static class DotCodeGenerateRequest {
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private String resourceId; // 关联资源ID
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private int pageCount; // 页数
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private double pageWidth; // 页面宽度（mm）
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private double pageHeight; // 页面高度（mm）
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private String outputFormat; // 输出格式（pdf/png/svg）
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private boolean overlayOnTemplate; // 是否叠加到模板上
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private String templateFileKey; // 模板文件OSS Key
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public String getResourceId() { return resourceId; }
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public void setResourceId(String id) { this.resourceId = id; }
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public int getPageCount() { return pageCount; }
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public void setPageCount(int count) { this.pageCount = count; }
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public double getPageWidth() { return pageWidth > 0 ? pageWidth : 210.0; }
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public double getPageHeight() { return pageHeight > 0 ? pageHeight : 297.0; }
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public String getOutputFormat() { return outputFormat != null ? outputFormat : "pdf"; }
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public boolean isOverlayOnTemplate() { return overlayOnTemplate; }
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public String getTemplateFileKey() { return templateFileKey; }
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}
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/** 点阵码生成结果 */
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public static class DotCodeGenerateResult {
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private String taskId;
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private String resourceId;
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private List<Long> dotCodeIds; // 分配的点阵码ID列表
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private String outputFileKey; // 生成的文件OSS Key
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private int pageCount;
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private long totalDots;
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private String status; // processing/completed/failed
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public String getTaskId() { return taskId; }
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public void setTaskId(String id) { this.taskId = id; }
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public List<Long> getDotCodeIds() { return dotCodeIds; }
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public void setDotCodeIds(List<Long> ids) { this.dotCodeIds = ids; }
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public String getOutputFileKey() { return outputFileKey; }
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public void setOutputFileKey(String key) { this.outputFileKey = key; }
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public String getStatus() { return status; }
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public void setStatus(String s) { this.status = s; }
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}
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// ============================================================
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// 核心方法实现
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// ============================================================
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/**
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* 批量生成点阵码资源包 POST /api/v1/dotcode/generate
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*
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* 流程：
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* 1. 分配全局唯一的点阵码ID范围
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* 2. 为每页生成OGP编码的点阵图案
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* 3. 如果需要叠加模板，合成到模板PDF上
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* 4. 上传生成结果到OSS
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* 5. 记录绑定关系到MySQL
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*/
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public DotCodeGenerateResult generateDotCodes(DotCodeGenerateRequest request) {
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logger.info(String.format(
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"生成点阵码: resource=%s, pages=%d, size=%.0fx%.0fmm",
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request.getResourceId(), request.getPageCount(),
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request.getPageWidth(), request.getPageHeight()
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));
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DotCodeGenerateResult result = new DotCodeGenerateResult();
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result.setTaskId(UUID.randomUUID().toString().replace("-", "").substring(0, 16));
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result.setStatus("processing");
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// 1. 分配点阵码ID
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List<Long> allocatedIds = allocateDotCodeIds(request.getPageCount());
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result.setDotCodeIds(allocatedIds);
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// 2. 为每页生成点阵码图案
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for (int i = 0; i < request.getPageCount(); i++) {
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long dotCodeId = allocatedIds.get(i);
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// 生成OGP编码点阵图案
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byte[][] dotPattern = generateOGPPattern(
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dotCodeId,
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request.getPageWidth(),
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request.getPageHeight()
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);
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// 记录绑定关系
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DotCodeBinding binding = new DotCodeBinding(
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dotCodeId, request.getResourceId(), i
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);
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binding.setAreaType("full_page");
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binding.setAreaX(0);
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binding.setAreaY(0);
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binding.setAreaWidth(request.getPageWidth());
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binding.setAreaHeight(request.getPageHeight());
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bindingCache.put(dotCodeId, binding);
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// 持久化到MySQL
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// dotCodeMapper.insertBinding(binding);
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}
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// 3. 如果叠加模板，合成PDF
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if (request.isOverlayOnTemplate() && request.getTemplateFileKey() != null) {
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// 下载模板PDF
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// byte[] templatePdf = ossClient.getObject(request.getTemplateFileKey());
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// 叠加点阵码图层
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// byte[] mergedPdf = pdfMerger.overlayDotCodes(templatePdf, dotPatterns);
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// 上传合成后的PDF
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// String outputKey = ossClient.putObject(mergedPdf, ...);
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// result.setOutputFileKey(outputKey);
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}
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result.setStatus("completed");
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result.setPageCount(request.getPageCount());
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result.setTotalDots((long) request.getPageCount() * DOTS_PER_PAGE);
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logger.info(String.format(
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"点阵码生成完成: task=%s, ids=[%d~%d], dots=%d",
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result.getTaskId(),
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allocatedIds.get(0),
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allocatedIds.get(allocatedIds.size() - 1),
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result.getTotalDots()
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));
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return result;
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}
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/**
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* 分配全局唯一的点阵码ID
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*
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* 使用原子递增方式保证ID全局唯一，防止多服务器实例间冲突。
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* 生产环境使用Redis分布式ID生成器。
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*
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* @param count 需要分配的ID数量
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* @return 分配的ID列表
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*/
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public synchronized List<Long> allocateDotCodeIds(int count) {
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List<Long> ids = new ArrayList<>();
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if (currentMaxId + count > ID_RANGE_END) {
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throw new RuntimeException("点阵码ID已耗尽，请联系管理员扩容");
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}
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for (int i = 0; i < count; i++) {
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currentMaxId++;
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ids.add(currentMaxId);
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}
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// 持久化当前最大ID（Redis或数据库）
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// redisTemplate.set("dot_code_max_id", String.valueOf(currentMaxId));
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logger.info(String.format(
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"分配点阵码ID: count=%d, range=[%d, %d]",
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count, ids.get(0), ids.get(ids.size() - 1)
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));
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return ids;
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}
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/**
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* 生成OGP编码的点阵图案
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*
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* OGP（Optical Glyph Pattern）编码原理：
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* 将点阵码ID编码为点的微小位移方向（上下左右4个方向），
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* 每组6x6点阵编码一组信息，整页覆盖实现全页面位置编码。
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*
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* @param dotCodeId 点阵码ID
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* @param pageWidthMm 页面宽度（毫米）
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* @param pageHeightMm 页面高度（毫米）
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* @return 点阵图案（2D数组，0=无偏移, 1=上, 2=右, 3=下, 4=左）
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*/
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public byte[][] generateOGPPattern(
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long dotCodeId,
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double pageWidthMm,
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double pageHeightMm
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) {
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// 计算网格尺寸
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int gridCols = (int) (pageWidthMm / DOT_SPACING_MM);
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int gridRows = (int) (pageHeightMm / DOT_SPACING_MM);
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byte[][] pattern = new byte[gridRows][gridCols];
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// 将点阵码ID编码为二进制位流
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long encodedId = dotCodeId;
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byte[] idBits = new byte[40]; // 40位足以表示10位十进制数
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for (int i = 0; i < 40; i++) {
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idBits[i] = (byte) ((encodedId >> (39 - i)) & 1);
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}
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// 填充点阵图案
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for (int row = 0; row < gridRows; row++) {
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for (int col = 0; col < gridCols; col++) {
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// 每个点的偏移方向由其位置和ID编码共同决定
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int groupRow = row / DOT_GRID_SIZE;
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int groupCol = col / DOT_GRID_SIZE;
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int localRow = row % DOT_GRID_SIZE;
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int localCol = col % DOT_GRID_SIZE;
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// 位置编码 + ID编码 混合
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int bitIndex = ((groupRow * (gridCols / DOT_GRID_SIZE) + groupCol)
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* DOT_GRID_SIZE * DOT_GRID_SIZE
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+ localRow * DOT_GRID_SIZE + localCol) % 40;
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// 偏移方向：0=无, 1=上, 2=右, 3=下, 4=左
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int positionHash = (row * 7 + col * 13 + (int) dotCodeId) % 5;
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pattern[row][col] = (byte) ((positionHash + idBits[bitIndex]) % 5);
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}
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}
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// 添加校验码区域（边缘4行/列作为同步标记和校验）
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addSyncMarkers(pattern, gridRows, gridCols);
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return pattern;
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}
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/**
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* 在点阵图案边缘添加同步标记和校验码
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* 摄像头采集后需要同步标记来确定方向和位置
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*/
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private void addSyncMarkers(byte[][] pattern, int rows, int cols) {
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// 顶部同步行：交替0和1
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for (int col = 0; col < cols; col++) {
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pattern[0][col] = (byte) (col % 2 == 0 ? 1 : 3);
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pattern[1][col] = (byte) (col % 2 == 0 ? 3 : 1);
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}
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// 左侧同步列
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for (int row = 0; row < rows; row++) {
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pattern[row][0] = (byte) (row % 2 == 0 ? 2 : 4);
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pattern[row][1] = (byte) (row % 2 == 0 ? 4 : 2);
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}
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// 右下角放置4x4校验码块
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// 校验码 = CRC-8(页面ID的低8位)
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// 用于摄像头快速验证解码是否正确
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}
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/**
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* 根据点阵码ID查询绑定的资源和页面信息
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*
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* @param dotCodeId 点阵码ID
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* @return 绑定关系（如果存在）
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*/
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public DotCodeBinding queryBinding(long dotCodeId) {
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// 先查缓存
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DotCodeBinding cached = bindingCache.get(dotCodeId);
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if (cached != null) {
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return cached;
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}
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// 缓存未命中，查数据库
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// DotCodeBinding binding = dotCodeMapper.selectByDotCodeId(dotCodeId);
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// if (binding != null) {
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// bindingCache.put(dotCodeId, binding);
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// }
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// return binding;
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return null;
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}
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/**
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* 查询资源关联的所有点阵码
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*/
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public List<DotCodeBinding> queryByResourceId(String resourceId) {
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// return dotCodeMapper.selectByResourceId(resourceId);
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return new ArrayList<>();
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}
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/**
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* 计算点阵码的SHA-256指纹（用于校验完整性）
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*/
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public String calculatePatternFingerprint(byte[][] pattern) {
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try {
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MessageDigest digest = MessageDigest.getInstance("SHA-256");
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for (byte[] row : pattern) {
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digest.update(row);
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}
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byte[] hash = digest.digest();
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StringBuilder sb = new StringBuilder();
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for (byte b : hash) {
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sb.append(String.format("%02x", b));
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}
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return sb.toString();
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} catch (NoSuchAlgorithmException e) {
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throw new RuntimeException("SHA-256不可用", e);
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}
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}
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}
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