refactor(data-management): 优化知识项目预览服务的文件转换逻辑

- 移除 docx4j 相关依赖和转换方法
- 统一 office 文件转换为 pdf 的处理方式，全部使用 libreoffice
- 删除单独的 docx 到 pdf 转换方法
- 重命名转换方法为 convertOfficeToPdfByLibreOffice
- 增强路径解析逻辑，添加多种候选路径处理
- 添加路径安全性验证和规范化处理
- 新增 extractRelativePathFromSegment 和 normalizeRelativePathValue 辅助方法
- 改进文件存在性检查和路径构建逻辑

backend/services/data-management-service/src/main/java/com/datamate/datamanagement/application/KnowledgeItemPreviewAsyncService.java

@@ -8,14 +8,11 @@ import com.fasterxml.jackson.databind.ObjectMapper;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
-import org.docx4j.Docx4J;
-import org.docx4j.openpackaging.packages.WordprocessingMLPackage;
 import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -82,11 +79,7 @@ public class KnowledgeItemPreviewAsyncService {
         ensureParentDirectory(targetPath);
 
         try {
-            if ("docx".equals(extension)) {
+            convertOfficeToPdfByLibreOffice(sourcePath, targetPath);
-                convertDocxToPdf(sourcePath, targetPath);
-            } else {
-                convertDocToPdfByLibreOffice(sourcePath, targetPath);
-            }
             updatePreviewStatus(item, KnowledgeItemPreviewStatus.READY, previewRelativePath, null);
         } catch (Exception e) {
             log.error("preview convert failed, itemId: {}", item.getId(), e);
@@ -94,14 +87,7 @@ public class KnowledgeItemPreviewAsyncService {
         }
     }
 
-    private void convertDocxToPdf(Path sourcePath, Path targetPath) throws Exception {
+    private void convertOfficeToPdfByLibreOffice(Path sourcePath, Path targetPath) throws Exception {
-        WordprocessingMLPackage wordMLPackage = WordprocessingMLPackage.load(sourcePath.toFile());
-        try (OutputStream outputStream = Files.newOutputStream(targetPath)) {
-            Docx4J.toPDF(wordMLPackage, outputStream);
-        }
-    }
-
-    private void convertDocToPdfByLibreOffice(Path sourcePath, Path targetPath) throws Exception {
         Path outputDir = targetPath.getParent();
         ensureParentDirectory(targetPath);
         List<String> command = List.of(
@@ -234,8 +220,70 @@ public class KnowledgeItemPreviewAsyncService {
     }
 
     private Path resolveKnowledgeItemStoragePath(String relativePath) {
-        String normalizedRelativePath = StringUtils.defaultString(relativePath).replace("/", java.io.File.separator);
+        if (StringUtils.isBlank(relativePath)) {
+            throw new IllegalArgumentException("invalid knowledge item path");
+        }
+        String normalizedInput = relativePath.replace("\\", PATH_SEPARATOR).trim();
         Path root = resolveUploadRootPath();
+        java.util.LinkedHashSet<Path> candidates = new java.util.LinkedHashSet<>();
+
+        Path inputPath = Paths.get(normalizedInput.replace(PATH_SEPARATOR, java.io.File.separator));
+        if (inputPath.isAbsolute()) {
+            Path normalizedAbsolute = inputPath.toAbsolutePath().normalize();
+            if (normalizedAbsolute.startsWith(root)) {
+                candidates.add(normalizedAbsolute);
+            }
+            String segmentRelativePath = extractRelativePathFromSegment(normalizedInput, KNOWLEDGE_ITEM_UPLOAD_DIR);
+            if (StringUtils.isNotBlank(segmentRelativePath)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, segmentRelativePath));
+            }
+            if (candidates.isEmpty()) {
+                throw new IllegalArgumentException("invalid knowledge item path");
+            }
+        } else {
+            String normalizedRelative = normalizeRelativePathValue(normalizedInput);
+            if (StringUtils.isNotBlank(normalizedRelative)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, normalizedRelative));
+            }
+            String segmentRelativePath = extractRelativePathFromSegment(normalizedInput, KNOWLEDGE_ITEM_UPLOAD_DIR);
+            if (StringUtils.isNotBlank(segmentRelativePath)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, segmentRelativePath));
+            }
+            if (StringUtils.isNotBlank(normalizedRelative)
+                    && !normalizedRelative.startsWith(KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR)
+                    && !normalizedRelative.equals(KNOWLEDGE_ITEM_UPLOAD_DIR)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR + normalizedRelative));
+            }
+        }
+
+        if (root.getFileName() != null && KNOWLEDGE_ITEM_UPLOAD_DIR.equals(root.getFileName().toString())) {
+            String normalizedRelative = normalizeRelativePathValue(normalizedInput);
+            if (StringUtils.isNotBlank(normalizedRelative)
+                    && normalizedRelative.startsWith(KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR)) {
+                String withoutPrefix = normalizedRelative.substring(KNOWLEDGE_ITEM_UPLOAD_DIR.length() + PATH_SEPARATOR.length());
+                if (StringUtils.isNotBlank(withoutPrefix)) {
+                    candidates.add(buildKnowledgeItemStoragePath(root, withoutPrefix));
+                }
+            }
+        }
+
+        Path fallback = null;
+        for (Path candidate : candidates) {
+            if (fallback == null) {
+                fallback = candidate;
+            }
+            if (Files.exists(candidate) && Files.isRegularFile(candidate)) {
+                return candidate;
+            }
+        }
+        if (fallback == null) {
+            throw new IllegalArgumentException("invalid knowledge item path");
+        }
+        return fallback;
+    }
+
+    private Path buildKnowledgeItemStoragePath(Path root, String relativePath) {
+        String normalizedRelativePath = StringUtils.defaultString(relativePath).replace(PATH_SEPARATOR, java.io.File.separator);
         Path target = root.resolve(normalizedRelativePath).toAbsolutePath().normalize();
         if (!target.startsWith(root)) {
             throw new IllegalArgumentException("invalid knowledge item path");
@@ -243,6 +291,36 @@ public class KnowledgeItemPreviewAsyncService {
         return target;
     }
 
+    private String extractRelativePathFromSegment(String rawPath, String segment) {
+        if (StringUtils.isBlank(rawPath) || StringUtils.isBlank(segment)) {
+            return null;
+        }
+        String normalized = rawPath.replace("\\", PATH_SEPARATOR).trim();
+        while (normalized.startsWith(PATH_SEPARATOR)) {
+            normalized = normalized.substring(1);
+        }
+        String segmentPrefix = segment + PATH_SEPARATOR;
+        int index = normalized.indexOf(segmentPrefix);
+        if (index < 0) {
+            return segment.equals(normalized) ? segment : null;
+        }
+        return normalizeRelativePathValue(normalized.substring(index));
+    }
+
+    private String normalizeRelativePathValue(String relativePath) {
+        if (StringUtils.isBlank(relativePath)) {
+            return "";
+        }
+        String normalized = relativePath.replace("\\", PATH_SEPARATOR).trim();
+        while (normalized.startsWith(PATH_SEPARATOR)) {
+            normalized = normalized.substring(1);
+        }
+        while (normalized.endsWith(PATH_SEPARATOR)) {
+            normalized = normalized.substring(0, normalized.length() - 1);
+        }
+        return normalized;
+    }
+
     private Path resolveUploadRootPath() {
         String uploadDir = dataManagementProperties.getFileStorage().getUploadDir();
         return Paths.get(uploadDir).toAbsolutePath().normalize();