jiahong
383 lines
14 KiB
Java
383 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/ResourceService.java - 资源管理业务服务
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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.logging.Logger;
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import java.util.stream.Collectors;
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/**
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* 资源管理业务服务
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*
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* 负责资源的完整生命周期管理：
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* - 资源元数据CRUD（MySQL）
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* - 文件存储管理（OSS/MinIO对象存储）
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* - 全文索引管理（Elasticsearch）
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* - CDN缓存管理
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* - 版本控制
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* - 数字水印
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*/
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public class ResourceService {
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private static final Logger logger =
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Logger.getLogger(ResourceService.class.getName());
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// ============================================================
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// 配置常量
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// ============================================================
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/** 支持的文件类型及最大大小（MB） */
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private static final Map<String, Integer> ALLOWED_FILE_TYPES = new HashMap<>();
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static {
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ALLOWED_FILE_TYPES.put("application/pdf", 100);
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ALLOWED_FILE_TYPES.put("application/vnd.ms-powerpoint", 200);
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ALLOWED_FILE_TYPES.put("application/vnd.openxmlformats-officedocument.presentationml.presentation", 200);
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ALLOWED_FILE_TYPES.put("image/jpeg", 20);
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ALLOWED_FILE_TYPES.put("image/png", 20);
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ALLOWED_FILE_TYPES.put("image/svg+xml", 10);
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ALLOWED_FILE_TYPES.put("video/mp4", 500);
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ALLOWED_FILE_TYPES.put("audio/mpeg", 50);
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}
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/** OSS存储桶名称 */
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private static final String OSS_BUCKET = "writech-resources";
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/** 缩略图存储前缀 */
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private static final String THUMBNAIL_PREFIX = "thumbnails/";
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/** Elasticsearch索引名称 */
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private static final String ES_INDEX = "writech_resources";
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// ============================================================
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// 数据模型
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// ============================================================
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/** 资源版本记录 */
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public static class ResourceVersion {
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private String id;
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private String resourceId;
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private int versionNumber;
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private String fileKey;
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private long fileSize;
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private String changeLog;
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private String operatorId;
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private Date createdAt;
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public String getId() { return id; }
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public void setId(String id) { this.id = 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 getVersionNumber() { return versionNumber; }
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public void setVersionNumber(int v) { this.versionNumber = v; }
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public String getFileKey() { return fileKey; }
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public void setFileKey(String key) { this.fileKey = key; }
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public String getChangeLog() { return changeLog; }
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public void setChangeLog(String log) { this.changeLog = log; }
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public Date getCreatedAt() { return createdAt; }
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}
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/** 数字水印配置 */
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public static class WatermarkConfig {
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private String text; // 水印文字（学校名+教师名）
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private float opacity; // 透明度（0.0-1.0）
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private int fontSize; // 字号
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private float rotation; // 旋转角度
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private String position; // 位置：center/bottom-right/tiled
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public WatermarkConfig(String text) {
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this.text = text;
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this.opacity = 0.15f;
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this.fontSize = 24;
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this.rotation = -30.0f;
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this.position = "tiled";
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}
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public String getText() { return text; }
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public float getOpacity() { return opacity; }
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public int getFontSize() { return fontSize; }
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public float getRotation() { return rotation; }
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public String getPosition() { return position; }
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}
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/** STS临时上传凭证 */
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public static class UploadCredential {
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private String accessKeyId;
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private String accessKeySecret;
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private String securityToken;
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private String bucket;
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private String objectKeyPrefix;
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private long expireTimeSeconds;
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public String getAccessKeyId() { return accessKeyId; }
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public String getAccessKeySecret() { return accessKeySecret; }
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public String getSecurityToken() { return securityToken; }
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public String getBucket() { return bucket; }
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public String getObjectKeyPrefix() { return objectKeyPrefix; }
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public long getExpireTimeSeconds() { return expireTimeSeconds; }
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}
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// ============================================================
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// 业务方法
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// ============================================================
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/**
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* 获取STS临时上传凭证
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*
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* 前端使用STS凭证直接上传到OSS，避免文件经过应用服务器。
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* STS凭证限制：仅允许PUT到指定前缀路径，有效期15分钟。
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*
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* @param uploaderId 上传者ID
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* @param fileType 文件MIME类型
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* @return STS临时凭证
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*/
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public UploadCredential getUploadCredential(String uploaderId, String fileType) {
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logger.info(String.format("获取上传凭证: user=%s, type=%s", uploaderId, fileType));
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// 校验文件类型
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if (!ALLOWED_FILE_TYPES.containsKey(fileType)) {
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throw new IllegalArgumentException("不支持的文件类型: " + fileType);
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}
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// 生成上传路径前缀：resources/{uploaderId}/{year}/{month}/
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Calendar cal = Calendar.getInstance();
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String prefix = String.format(
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"resources/%s/%d/%02d/",
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uploaderId,
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cal.get(Calendar.YEAR),
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cal.get(Calendar.MONTH) + 1
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);
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// 调用OSS STS服务获取临时凭证
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// AssumeRoleResponse response = stsClient.assumeRole(
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// roleArn, policy, sessionName, 900 // 15分钟
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// );
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UploadCredential credential = new UploadCredential();
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// credential.accessKeyId = response.getCredentials().getAccessKeyId();
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// credential.accessKeySecret = response.getCredentials().getAccessKeySecret();
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// credential.securityToken = response.getCredentials().getSecurityToken();
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// credential.bucket = OSS_BUCKET;
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// credential.objectKeyPrefix = prefix;
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// credential.expireTimeSeconds = 900;
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return credential;
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}
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/**
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* 创建资源记录（上传完成后调用）
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*
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* @param metadata 资源元数据
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* @return 创建的资源ID
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*/
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public String createResource(Map<String, Object> metadata) {
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String name = (String) metadata.get("name");
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String fileKey = (String) metadata.get("file_key");
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String mimeType = (String) metadata.get("mime_type");
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logger.info(String.format("创建资源: name=%s, key=%s", name, fileKey));
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// 生成资源ID
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String resourceId = UUID.randomUUID().toString().replace("-", "");
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// 自动生成缩略图
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generateThumbnailAsync(resourceId, fileKey, mimeType);
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// 插入MySQL元数据
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// resourceMapper.insert(resource);
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// 创建初始版本记录
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createVersion(resourceId, fileKey, "初始版本", (String) metadata.get("uploader_id"));
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// 同步索引到Elasticsearch
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indexToElasticsearch(resourceId, metadata);
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logger.info("资源创建成功: id=" + resourceId);
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return resourceId;
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}
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/**
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* 更新资源（新版本上传）
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*
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* 资源更新不删除旧版本，而是创建新版本记录，
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* 支持版本回滚。更新后需刷新CDN缓存。
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*/
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public void updateResource(String resourceId, Map<String, Object> updateData) {
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logger.info("更新资源: id=" + resourceId);
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String newFileKey = (String) updateData.get("file_key");
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String changeLog = (String) updateData.get("change_log");
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String operatorId = (String) updateData.get("operator_id");
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// 创建新版本
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if (newFileKey != null) {
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createVersion(resourceId, newFileKey, changeLog, operatorId);
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}
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// 更新MySQL元数据
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// resourceMapper.update(resourceId, updateData);
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// 更新Elasticsearch索引
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updateElasticsearchIndex(resourceId, updateData);
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// 刷新CDN缓存
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refreshCdnCache(resourceId);
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}
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/**
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* 创建版本记录
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*/
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private void createVersion(
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String resourceId, String fileKey, String changeLog, String operatorId
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) {
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// 查询当前最大版本号
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// int maxVersion = versionMapper.selectMaxVersion(resourceId);
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ResourceVersion version = new ResourceVersion();
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version.setId(UUID.randomUUID().toString().replace("-", ""));
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version.setResourceId(resourceId);
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version.setVersionNumber(1); // maxVersion + 1
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version.setFileKey(fileKey);
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version.setChangeLog(changeLog);
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// versionMapper.insert(version);
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logger.info(String.format(
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"创建版本: resource=%s, version=%d", resourceId, version.getVersionNumber()
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));
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}
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/**
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* 异步生成缩略图
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*
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* 根据文件类型采用不同策略：
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* - PDF: 渲染第一页为图片
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* - PPT: 提取封面幻灯片
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* - 图片: 直接缩放
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* - 视频: 提取关键帧
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*/
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private void generateThumbnailAsync(String resourceId, String fileKey, String mimeType) {
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// @Async 异步执行
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logger.info(String.format(
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"生成缩略图: resource=%s, type=%s", resourceId, mimeType
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));
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// 根据MIME类型选择缩略图生成策略
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// if (mimeType.equals("application/pdf")) {
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// PDDocument doc = PDDocument.load(ossClient.getObject(fileKey));
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// PDFRenderer renderer = new PDFRenderer(doc);
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// BufferedImage image = renderer.renderImageWithDPI(0, 150);
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// // 缩放为缩略图尺寸(320x240)
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// BufferedImage thumb = ImageUtils.resize(image, 320, 240);
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// // 上传缩略图到OSS
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// ossClient.putObject(THUMBNAIL_PREFIX + resourceId + ".jpg", thumb);
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// }
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}
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/**
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* 索引资源到Elasticsearch
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*
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* 索引字段：名称、描述、标签、学科、年级、出版社、类型
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* 支持中文分词（IK分词器）
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*/
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private void indexToElasticsearch(String resourceId, Map<String, Object> metadata) {
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logger.info("索引资源到ES: id=" + resourceId);
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// Map<String, Object> document = new HashMap<>();
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// document.put("id", resourceId);
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// document.put("name", metadata.get("name"));
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// document.put("description", metadata.get("description"));
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// document.put("tags", metadata.get("tags"));
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// document.put("subject", metadata.get("subject"));
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// document.put("grade", metadata.get("grade"));
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// document.put("publisher", metadata.get("publisher"));
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// document.put("type", metadata.get("type"));
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// document.put("school_id", metadata.get("school_id"));
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// document.put("audit_status", "PENDING");
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// document.put("created_at", new Date());
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// IndexRequest request = new IndexRequest(ES_INDEX)
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// .id(resourceId)
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// .source(document);
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// elasticsearchClient.index(request);
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}
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/**
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* 更新Elasticsearch索引
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*/
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private void updateElasticsearchIndex(String resourceId, Map<String, Object> updateData) {
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// UpdateRequest request = new UpdateRequest(ES_INDEX, resourceId)
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// .doc(updateData);
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// elasticsearchClient.update(request);
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}
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/**
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* 刷新CDN缓存
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*
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* 资源更新后需要刷新CDN节点缓存，确保终端获取最新版本。
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*/
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private void refreshCdnCache(String resourceId) {
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logger.info("刷新CDN缓存: resource=" + resourceId);
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// String cdnUrl = String.format("https://cdn.writech.com/resources/%s", resourceId);
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// cdnClient.refreshObjectCaches(Collections.singletonList(cdnUrl));
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}
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/**
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* 添加数字水印
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*
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* 下载资源时可选添加数字水印，水印包含学校和教师标识，
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* 用于版权保护和追踪。
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*
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* @param fileBytes 原始文件字节
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* @param config 水印配置
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* @return 添加水印后的文件字节
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*/
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public byte[] addWatermark(byte[] fileBytes, WatermarkConfig config) {
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logger.info("添加数字水印: text=" + config.getText());
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// PDF水印添加
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// PDDocument doc = PDDocument.load(fileBytes);
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// for (PDPage page : doc.getPages()) {
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// PDPageContentStream cs = new PDPageContentStream(doc, page, APPEND, true);
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// cs.setFont(PDType1Font.HELVETICA, config.getFontSize());
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// cs.setNonStrokingColor(200, 200, 200); // 浅灰色
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// // 平铺水印
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// for (float y = 0; y < page.getMediaBox().getHeight(); y += 100) {
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// for (float x = 0; x < page.getMediaBox().getWidth(); x += 200) {
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// cs.beginText();
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// Matrix matrix = Matrix.getRotateInstance(
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// Math.toRadians(config.getRotation()), x, y
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// );
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// cs.setTextMatrix(matrix);
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// cs.showText(config.getText());
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// cs.endText();
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// }
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// }
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// cs.close();
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// }
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return fileBytes;
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}
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/**
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* 删除资源（软删除）
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*
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* 不物理删除文件，仅标记为已删除状态。
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* OSS文件通过生命周期策略定期清理。
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*/
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public void deleteResource(String resourceId, String operatorId) {
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logger.info(String.format(
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"删除资源: id=%s, operator=%s", resourceId, operatorId
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));
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// 软删除：更新状态
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// resourceMapper.updateStatus(resourceId, "DELETED");
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// 从ES索引中移除
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// elasticsearchClient.delete(new DeleteRequest(ES_INDEX, resourceId));
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// 刷新CDN
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refreshCdnCache(resourceId);
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}
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}
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