feat(笔记预览): 实现大文件分块加载功能

添加分块加载API接口及前端实现，支持大文件(>500KB)的分页加载，提升大文件预览体验
后端实现分块逻辑并添加权限检查，前端添加加载提示和滚动加载功能

biji-houdaun/src/main/java/com/test/bijihoudaun/controller/MarkdownController.java

@@ -3,6 +3,7 @@ package com.test.bijihoudaun.controller;
 import cn.hutool.core.util.ObjectUtil;
 import com.test.bijihoudaun.common.response.R;
 import com.test.bijihoudaun.entity.MarkdownFile;
+import com.test.bijihoudaun.entity.MarkdownFileChunk;
 import com.test.bijihoudaun.entity.MarkdownFileVO;
 import com.test.bijihoudaun.service.MarkdownFileService;
 import com.test.bijihoudaun.util.SecurityUtil;
@@ -117,4 +118,26 @@ public class MarkdownController {
         return R.success(files);
     }
 
+    @Operation(summary = "分块加载Markdown文件内容", description = "用于大文件（> 500KB）的分页加载")
+    @Parameters({
+        @Parameter(name = "id", description = "文件ID", required = true),
+        @Parameter(name = "chunkIndex", description = "块索引（从0开始）", required = false),
+        @Parameter(name = "chunkSize", description = "块大小（字符数），默认10000", required = false)
+    })
+    @GetMapping("/{id}/chunk")
+    public R<MarkdownFileChunk> getMarkdownChunk(
+            @PathVariable Long id,
+            @RequestParam(defaultValue = "0") int chunkIndex,
+            @RequestParam(defaultValue = "10000") int chunkSize) {
+        
+        // 获取当前认证状态
+        boolean isAuthenticated = SecurityUtil.isUserAuthenticated();
+        
+        MarkdownFileChunk chunk = markdownFileService.getMarkdownChunk(id, chunkIndex, chunkSize, isAuthenticated);
+        if (ObjectUtil.isNotNull(chunk)) {
+            return R.success(chunk);
+        }
+        return R.fail("文件未找到");
+    }
+
 }

biji-houdaun/src/main/java/com/test/bijihoudaun/entity/MarkdownFileChunk.java

@@ -0,0 +1,46 @@
+package com.test.bijihoudaun.entity;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Data;
+
+import java.io.Serializable;
+
+/**
+ * Markdown文件分块加载响应实体
+ * 用于大文件分页加载
+ */
+@Data
+@Schema(name = "Markdown文件分块")
+public class MarkdownFileChunk implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    @Schema(description = "当前块的内容")
+    private String chunk;
+
+    @Schema(description = "当前块索引（从0开始）")
+    private int chunkIndex;
+
+    @Schema(description = "总块数")
+    private int totalChunks;
+
+    @Schema(description = "是否还有更多块")
+    private boolean hasMore;
+
+    @Schema(description = "笔记ID")
+    @JsonFormat(shape = JsonFormat.Shape.STRING)
+    private Long fileId;
+
+    @Schema(description = "笔记标题")
+    private String title;
+
+    @Schema(description = "是否私密 0-公开 1-私密")
+    private Integer isPrivate;
+
+    @Schema(description = "总字符数")
+    private long totalLength;
+
+    @Schema(description = "当前块字符数")
+    private int chunkLength;
+}

biji-houdaun/src/main/java/com/test/bijihoudaun/service/MarkdownFileService.java

@@ -2,6 +2,7 @@ package com.test.bijihoudaun.service;
 
 import com.baomidou.mybatisplus.extension.service.IService;
 import com.test.bijihoudaun.entity.MarkdownFile;
+import com.test.bijihoudaun.entity.MarkdownFileChunk;
 import com.test.bijihoudaun.entity.MarkdownFileVO;
 
 import java.util.List;
@@ -66,4 +67,15 @@ public interface MarkdownFileService extends IService<MarkdownFile> {
      * @return 文件列表
      */
     List<MarkdownFileVO> getRecentFiles(int limit);
+
+    /**
+     * 分块加载Markdown文件内容
+     * 用于大文件（> 500KB）的分页加载
+     * @param id 文件ID
+     * @param chunkIndex 块索引（从0开始）
+     * @param chunkSize 块大小（字符数），默认10000
+     * @param isAuthenticated 是否已认证
+     * @return 文件块对象
+     */
+    MarkdownFileChunk getMarkdownChunk(Long id, int chunkIndex, int chunkSize, boolean isAuthenticated);
 }

biji-houdaun/src/main/java/com/test/bijihoudaun/service/impl/MarkdownFileServiceImpl.java

@@ -8,6 +8,7 @@ import com.baomidou.mybatisplus.core.conditions.update.LambdaUpdateWrapper;
 import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
 import com.test.bijihoudaun.entity.ImageName;
 import com.test.bijihoudaun.entity.MarkdownFile;
+import com.test.bijihoudaun.entity.MarkdownFileChunk;
 import com.test.bijihoudaun.entity.MarkdownFileVO;
 import com.test.bijihoudaun.mapper.ImageNameMapper;
 import com.test.bijihoudaun.mapper.MarkdownFileMapper;
@@ -156,4 +157,92 @@ public class MarkdownFileServiceImpl
         return markdownFileMapper.selectRecentWithGrouping(limit);
     }
 
+    @Override
+    public MarkdownFileChunk getMarkdownChunk(Long id, int chunkIndex, int chunkSize, boolean isAuthenticated) {
+        // 获取文件基本信息（不包含内容）
+        MarkdownFileVO fileVO = markdownFileMapper.selectByIdWithGrouping(id);
+        if (fileVO == null) {
+            return null;
+        }
+        
+        // 检查权限：私密笔记需要登录
+        if (fileVO.getIsPrivate() != null && fileVO.getIsPrivate() == 1 && !isAuthenticated) {
+            MarkdownFileChunk chunk = new MarkdownFileChunk();
+            chunk.setFileId(id);
+            chunk.setTitle(fileVO.getTitle());
+            chunk.setIsPrivate(fileVO.getIsPrivate());
+            chunk.setChunk("该笔记为私密笔记，请登录后查看");
+            chunk.setChunkIndex(0);
+            chunk.setTotalChunks(1);
+            chunk.setHasMore(false);
+            chunk.setTotalLength(0);
+            chunk.setChunkLength(0);
+            return chunk;
+        }
+        
+        // 获取完整内容
+        MarkdownFile file = this.getById(id);
+        if (file == null || file.getContent() == null) {
+            return null;
+        }
+        
+        String fullContent = file.getContent();
+        int totalLength = fullContent.length();
+        
+        // 如果文件小于 500KB（约50万字符），直接返回全部内容
+        if (totalLength <= 500000) {
+            MarkdownFileChunk chunk = new MarkdownFileChunk();
+            chunk.setFileId(id);
+            chunk.setTitle(file.getTitle());
+            chunk.setIsPrivate(file.getIsPrivate());
+            chunk.setChunk(fullContent);
+            chunk.setChunkIndex(0);
+            chunk.setTotalChunks(1);
+            chunk.setHasMore(false);
+            chunk.setTotalLength(totalLength);
+            chunk.setChunkLength(totalLength);
+            return chunk;
+        }
+        
+        // 大文件分页加载
+        // 计算总块数
+        int totalChunks = (int) Math.ceil((double) totalLength / chunkSize);
+        
+        // 确保 chunkIndex 在有效范围内
+        if (chunkIndex < 0) {
+            chunkIndex = 0;
+        }
+        if (chunkIndex >= totalChunks) {
+            chunkIndex = totalChunks - 1;
+        }
+        
+        // 计算当前块的起止位置
+        int start = chunkIndex * chunkSize;
+        int end = Math.min(start + chunkSize, totalLength);
+        
+        // 截取内容
+        String chunkContent = fullContent.substring(start, end);
+        
+        // 如果不是第一块，尝试从完整的换行处开始
+        if (chunkIndex > 0 && start < totalLength) {
+            // 找到第一个换行符，从下一行开始显示
+            int firstNewLine = chunkContent.indexOf('\n');
+            if (firstNewLine > 0) {
+                chunkContent = chunkContent.substring(firstNewLine + 1);
+            }
+        }
+        
+        MarkdownFileChunk chunk = new MarkdownFileChunk();
+        chunk.setFileId(id);
+        chunk.setTitle(file.getTitle());
+        chunk.setIsPrivate(file.getIsPrivate());
+        chunk.setChunk(chunkContent);
+        chunk.setChunkIndex(chunkIndex);
+        chunk.setTotalChunks(totalChunks);
+        chunk.setHasMore(chunkIndex < totalChunks - 1);
+        chunk.setTotalLength(totalLength);
+        chunk.setChunkLength(chunkContent.length());
+        
+        return chunk;
+    }
 }

biji-qianduan/src/api/CommonApi.js

@@ -16,6 +16,10 @@ export const markdownAll = () => axiosApi.get(`/api/markdown`);
 // 预览markdown文件
 export const Preview = (id) => axiosApi.get(`/api/markdown/${id}`);
 
+// 分块加载markdown文件内容（用于大文件）
+export const PreviewChunk = (id, chunkIndex = 0, chunkSize = 10000) => 
+    axiosApi.get(`/api/markdown/${id}/chunk?chunkIndex=${chunkIndex}&chunkSize=${chunkSize}`);
+
 // 创建分类分组
 export const addGroupings = (group) => {
     return axiosApi.post('/api/groupings', group);

biji-qianduan/src/components/HomePage.vue

@@ -33,6 +33,7 @@
             :file="selectedFile"
             :is-mobile="isMobile"
             :is-user-logged-in="userStore.isLoggedIn"
+            :has-more-chunks="hasMoreChunks"
             @back="selectedFile = null"
             @edit="editNote(selectedFile)"
             @delete="deleteNote(selectedFile)"
@@ -66,8 +67,11 @@
               <el-icon class="is-loading"><Loading /></el-icon>
               <span>加载中...</span>
             </div>
-            <div v-else-if="hasMoreFiles && !showEditor && !selectedFile" class="load-more-trigger">
+            <div v-else-if="hasMoreFiles && !showEditor && !selectedFile" class="load-more-hint">
-              <el-button @click="loadMoreFiles" type="primary" plain>加载更多</el-button>
+              <span>继续滚动加载更多...</span>
+            </div>
+            <div v-else-if="!hasMoreFiles && displayedFiles.length > 0" class="no-more-hint">
+              <span>没有更多笔记了</span>
             </div>
           </div>
         </div>
@@ -140,6 +144,7 @@ import {
   groupingAll,
   markdownList,
   Preview,
+  PreviewChunk,
   updateMarkdown,
   searchMarkdown,
   deleteMarkdown,
@@ -180,6 +185,7 @@ const displayedFiles = ref([]);
 const currentPage = ref(0);
 const pageSize = ref(16);
 const isLoadingMore = ref(false);
+const loadCount = ref(0); // 记录加载次数，用于动态增加加载数量
 const noteListWrapper = ref(null);
 const showEditor = ref(false);
 const selectedFile = ref(null);
@@ -203,6 +209,12 @@ const vditorReady = ref(false);
 // 提供给子组件使用
 provide('vditorReady', vditorReady);
 
+// 大文件分块加载状态
+const currentChunkIndex = ref(0);
+const hasMoreChunks = ref(false);
+const isLoadingChunk = ref(false);
+const totalChunks = ref(0);
+
 // Data for dialogs
 const itemToRename = ref(null);
 const fileToImport = ref(null);
@@ -258,6 +270,7 @@ const resetToHomeView = async () => {
   searchKeyword.value = '';
   activeMenu.value = 'all';
   currentPage.value = 0;
+  loadCount.value = 0; // 重置加载计数
   try {
     groupMarkdownFiles.value = await getRecentFiles(100) || [];
     updateDisplayedFiles();
@@ -269,9 +282,21 @@ const resetToHomeView = async () => {
   }
 };
 
+// 计算动态加载数量：基础16个，每次增加8个，最多48个
+const getDynamicPageSize = () => {
+  const baseSize = 16;
+  const increment = 8;
+  const maxSize = 48;
+  return Math.min(baseSize + loadCount.value * increment, maxSize);
+};
+
 const updateDisplayedFiles = () => {
   const start = 0;
-  const end = (currentPage.value + 1) * pageSize.value;
+  const dynamicPageSize = getDynamicPageSize();
+  // 计算实际显示数量：首次16个，之后动态增加
+  const end = displayedFiles.value.length === 0 
+    ? dynamicPageSize 
+    : displayedFiles.value.length + dynamicPageSize;
   displayedFiles.value = groupMarkdownFiles.value.slice(start, end);
 };
 
@@ -280,6 +305,7 @@ const loadMoreFiles = () => {
   isLoadingMore.value = true;
   
   setTimeout(() => {
+    loadCount.value++;
     currentPage.value++;
     updateDisplayedFiles();
     isLoadingMore.value = false;
@@ -288,11 +314,21 @@ const loadMoreFiles = () => {
 
 const handleScroll = (e) => {
   const { scrollTop, scrollHeight, clientHeight } = e.target;
-  if (scrollHeight - scrollTop - clientHeight < 100 && hasMoreFiles.value && !isLoadingMore.value) {
+  // 距离底部 200px 时自动加载，给用户更流畅的体验
+  if (scrollHeight - scrollTop - clientHeight < 200 && hasMoreFiles.value && !isLoadingMore.value) {
     loadMoreFiles();
   }
 };
 
+// 预览区域滚动处理（用于大文件分块加载）
+const handlePreviewScroll = (e) => {
+  const { scrollTop, scrollHeight, clientHeight } = e.target;
+  // 距离底部 300px 时加载下一页内容
+  if (scrollHeight - scrollTop - clientHeight < 300 && hasMoreChunks.value && !isLoadingChunk.value) {
+    loadMoreContent();
+  }
+};
+
 // Event Handlers from Components
 const handleSelectFile = async (data) => {
   resetEdit();
@@ -300,6 +336,7 @@ const handleSelectFile = async (data) => {
     const files = await markdownList(data.id);
     groupMarkdownFiles.value = files || [];
     currentPage.value = 0;
+    loadCount.value = 0; // 重置加载计数
     updateDisplayedFiles();
     selectedFile.value = null;
     showEditor.value = false;
@@ -377,26 +414,71 @@ const previewFile = async (file) => {
   }
   // 重置渲染缓存，确保每次打开笔记都重新渲染
   lastRenderedKey = null;
+  // 重置分块加载状态
+  currentChunkIndex.value = 0;
+  hasMoreChunks.value = false;
+  isLoadingChunk.value = false;
+  totalChunks.value = 0;
+  
   // 先立即显示预览页（加载状态），让用户感知到响应
   selectedFile.value = { ...file, content: '', isLoading: true, isRendering: false };
   showEditor.value = false;
 
-  // 异步加载内容
+  // 异步加载内容（使用分块加载）
+  await loadNoteChunk(file.id, 0);
+};
+
+// 分块加载笔记内容
+const loadNoteChunk = async (fileId, chunkIndex) => {
+  if (isLoadingChunk.value) return;
+  
+  isLoadingChunk.value = true;
   try {
-    const content = await Preview(file.id) || '';
+    const chunkData = await PreviewChunk(fileId, chunkIndex, 10000);
-    // 内容加载完成后更新
+    
-    if (selectedFile.value && selectedFile.value.id === file.id) {
+    if (selectedFile.value && selectedFile.value.id === fileId) {
+      // 更新分块加载状态
+      currentChunkIndex.value = chunkData.chunkIndex;
+      hasMoreChunks.value = chunkData.hasMore;
+      totalChunks.value = chunkData.totalChunks;
+      
+      // 如果是第一块，直接设置内容；否则追加内容
+      let newContent;
+      if (chunkIndex === 0) {
+        newContent = chunkData.chunk;
+      } else {
+        newContent = selectedFile.value.content + chunkData.chunk;
+      }
+      
       // 如果 Vditor 渲染引擎未就绪，显示渲染中状态
       const isRendering = !vditorReady.value;
-      selectedFile.value = { ...file, content, isLoading: false, isRendering };
+      
+      selectedFile.value = { 
+        ...selectedFile.value, 
+        content: newContent, 
+        isLoading: false, 
+        isRendering,
+        title: chunkData.title || selectedFile.value.title,
+        isPrivate: chunkData.isPrivate !== undefined ? chunkData.isPrivate : selectedFile.value.isPrivate
+      };
     }
   } catch (error) {
     // 错误已在 axios 拦截器中显示，这里不再重复显示
     console.error('获取笔记内容失败:', error);
     selectedFile.value = null;
+  } finally {
+    isLoadingChunk.value = false;
   }
 };
 
+// 加载更多内容（滚动到底部时调用）
+const loadMoreContent = async () => {
+  if (!selectedFile.value || !hasMoreChunks.value || isLoadingChunk.value) return;
+  
+  const nextChunkIndex = currentChunkIndex.value + 1;
+  await loadNoteChunk(selectedFile.value.id, nextChunkIndex);
+};
+
 const editNote = (file) => {
   editData.value = { ...file };
   showEditor.value = true;
@@ -474,6 +556,7 @@ const handleSearch = async () => {
   try {
     groupMarkdownFiles.value = await searchMarkdown(searchKeyword.value) || [];
     currentPage.value = 0;
+    loadCount.value = 0; // 重置加载计数
     updateDisplayedFiles();
     selectedFile.value = null;
     showEditor.value = false;
@@ -669,6 +752,10 @@ const renderMarkdown = async (file) => {
               img.setAttribute('loading', 'lazy');
             }
           });
+          // 添加滚动监听，用于大文件分块加载
+          if (hasMoreChunks.value) {
+            previewElement.addEventListener('scroll', handlePreviewScroll);
+          }
         }
       });
       lastRenderedKey = renderKey;
@@ -776,4 +863,68 @@ watch(showEditor, (isEditor) => {
   justify-content: center;
   padding: 20px;
 }
+
+/* 没有更多笔记了 - 美化样式 */
+.no-more-hint {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  padding: 30px 20px;
+  margin: 10px 0;
+}
+
+.no-more-hint span {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 12px 24px;
+  background: linear-gradient(135deg, #f5f7fa 0%, #e4e7ed 100%);
+  border-radius: 24px;
+  color: #909399;
+  font-size: 14px;
+  font-weight: 500;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
+  border: 1px solid #ebeef5;
+}
+
+.no-more-hint span::before {
+  content: '';
+  display: inline-block;
+  width: 4px;
+  height: 4px;
+  background-color: #c0c4cc;
+  border-radius: 50%;
+}
+
+.no-more-hint span::after {
+  content: '';
+  display: inline-block;
+  width: 4px;
+  height: 4px;
+  background-color: #c0c4cc;
+  border-radius: 50%;
+}
+
+/* 暗黑模式适配 */
+.dark-theme .no-more-hint span {
+  background: linear-gradient(135deg, #2c2c3d 0%, #1e1e2f 100%);
+  color: #606266;
+  border-color: #2c2c3d;
+}
+
+.dark-theme .no-more-hint span::before,
+.dark-theme .no-more-hint span::after {
+  background-color: #606266;
+}
+
+/* 继续滚动加载更多提示 */
+.load-more-hint {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  padding: 20px;
+  color: var(--el-color-primary);
+  font-size: 14px;
+  font-weight: 500;
+}
 </style>

biji-qianduan/src/components/home/NotePreview.vue

@@ -51,6 +51,11 @@
       <el-icon class="loading-icon is-loading"><Loading /></el-icon>
       <span class="loading-text">正在渲染...</span>
     </div>
+    <!-- 大文件分块加载提示 -->
+    <div v-if="file.hasMoreChunks" class="chunk-loading-hint">
+      <el-icon class="is-loading"><Loading /></el-icon>
+      <span>加载更多内容...</span>
+    </div>
   </div>
 </template>
 
@@ -64,6 +69,10 @@ const props = defineProps({
   },
   isMobile: Boolean,
   isUserLoggedIn: Boolean,
+  hasMoreChunks: {
+    type: Boolean,
+    default: false
+  }
 });
 
 const emit = defineEmits([
@@ -192,4 +201,25 @@ const handleExport = (format) => {
   font-size: 14px;
   color: var(--text-color-secondary);
 }
+
+/* 分块加载提示 */
+.chunk-loading-hint {
+  position: absolute;
+  bottom: 20px;
+  left: 50%;
+  transform: translateX(-50%);
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 8px 16px;
+  background-color: rgba(255, 255, 255, 0.9);
+  border-radius: 20px;
+  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
+  color: var(--el-color-primary);
+  font-size: 14px;
+}
+
+.dark-theme .chunk-loading-hint {
+  background-color: rgba(30, 30, 47, 0.9);
+}
 </style>