feat(novel-admin): 新增小说下载功能

为满足部分用户将小说下载至手机阅读的需求，新增管理后台小说下载功能。

该功能未在前台开放，主要基于以下考量：
1. 防止用户流失，保障网站留存率及广告收入
2. 避免大量下载请求带来额外的服务器流量与带宽压力

通过后台受限访问的方式，在满足特定需求的同时，兼顾系统稳定性与商业可持续性。

novel-admin/src/main/java/com/java2nb/common/config/Constant.java

@@ -15,7 +15,7 @@ public class Constant {
     //通知公告阅读状态-已读
     public static int OA_NOTIFY_READ_YES = 1;
     //部门根节点id
-    public static Long DEPT_ROOT_ID = 0l;
+    public static Long DEPT_ROOT_ID = 0L;
     //缓存方式
     public static String CACHE_TYPE_REDIS = "redis";
 
@@ -23,5 +23,6 @@ public class Constant {
 
     public static final String UPLOAD_FILES_PREFIX = "/files/";
 
+    public static final String BOOK_IS_DOWNLOADING_KEY = "bookIsDownloading:";
 
 }

novel-admin/src/main/java/com/java2nb/common/utils/SortWhitelistUtil.java

@@ -11,7 +11,7 @@ import java.util.Set;
 public class SortWhitelistUtil {
 
     // 白名单字段
-    private static final Set<String> ALLOWED_COLUMNS = Set.of("id", "name", "order_num");
+    private static final Set<String> ALLOWED_COLUMNS = Set.of("id", "name", "order_num","index_num");
 
     // 白名单排序方式
     private static final Set<String> ALLOWED_ORDERS = Set.of("asc", "desc");

novel-admin/src/main/java/com/java2nb/novel/controller/BookController.java

@@ -1,10 +1,24 @@
 package com.java2nb.novel.controller;
 
+import java.io.OutputStream;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
+import com.java2nb.common.config.Constant;
+import com.java2nb.novel.domain.BookContentDO;
+import com.java2nb.novel.domain.BookIndexDO;
+import com.java2nb.novel.service.BookContentService;
+import com.java2nb.novel.service.BookIndexService;
+import lombok.extern.slf4j.Slf4j;
 import org.apache.shiro.authz.annotation.RequiresPermissions;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.redis.core.RedisTemplate;
 import org.springframework.stereotype.Controller;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -22,6 +36,9 @@ import com.java2nb.common.utils.PageBean;
 import com.java2nb.common.utils.Query;
 import com.java2nb.common.utils.R;
 
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
+
 /**
  * 小说表
  *
@@ -30,12 +47,34 @@ import com.java2nb.common.utils.R;
  * @date 2020-12-01 03:49:46
  */
 
+@Slf4j
 @Controller
 @RequestMapping("/novel/book")
 public class BookController {
+
     @Autowired
     private BookService bookService;
 
+    @Autowired
+    private RedisTemplate<String, String> redisTemplate;
+
+    @Autowired
+    private BookIndexService bookIndexService;
+
+    @Autowired
+    private BookContentService bookContentService;
+
+
+    private final Pattern PATTERN_BR = Pattern.compile("<br\\s*/?>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_NBSP = Pattern.compile("&nbsp;", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_ANCHOR_OPEN = Pattern.compile("<a[^>]*>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_ANCHOR_CLOSE = Pattern.compile("</a>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_DIV_OPEN = Pattern.compile("<div[^>]*>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_DIV_CLOSE = Pattern.compile("</div>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_EMPTY_PARAGRAPH_WITH_LINK = Pattern.compile("<p[^>]*>[^<]*<a[^>]*>[^<]*</a>\\s*</p>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_P_OPEN = Pattern.compile("<p[^>]*>", Pattern.CASE_INSENSITIVE);
+    private final Pattern PATTERN_P_CLOSE = Pattern.compile("</p>", Pattern.CASE_INSENSITIVE);
+
     @GetMapping()
     @RequiresPermissions("novel:book:book")
     String Book() {
@@ -66,7 +105,7 @@ public class BookController {
     @GetMapping("/edit/{id}")
     @RequiresPermissions("novel:book:edit")
     String edit(@PathVariable("id") Long id, Model model) {
-            BookDO book = bookService.get(id);
+        BookDO book = bookService.get(id);
         model.addAttribute("book", book);
         return "novel/book/edit";
     }
@@ -75,7 +114,7 @@ public class BookController {
     @GetMapping("/detail/{id}")
     @RequiresPermissions("novel:book:detail")
     String detail(@PathVariable("id") Long id, Model model) {
-			BookDO book = bookService.get(id);
+        BookDO book = bookService.get(id);
         model.addAttribute("book", book);
         return "novel/book/detail";
     }
@@ -87,7 +126,7 @@ public class BookController {
     @ResponseBody
     @PostMapping("/save")
     @RequiresPermissions("novel:book:add")
-    public R save( BookDO book) {
+    public R save(BookDO book) {
         if (bookService.save(book) > 0) {
             return R.ok();
         }
@@ -101,8 +140,8 @@ public class BookController {
     @ResponseBody
     @RequestMapping("/update")
     @RequiresPermissions("novel:book:edit")
-    public R update( BookDO book) {
+    public R update(BookDO book) {
-            bookService.update(book);
+        bookService.update(book);
         return R.ok();
     }
 
@@ -113,7 +152,7 @@ public class BookController {
     @PostMapping("/remove")
     @ResponseBody
     @RequiresPermissions("novel:book:remove")
-    public R remove( Long id) {
+    public R remove(Long id) {
         if (bookService.remove(id) > 0) {
             return R.ok();
         }
@@ -128,8 +167,83 @@ public class BookController {
     @ResponseBody
     @RequiresPermissions("novel:book:batchRemove")
     public R remove(@RequestParam("ids[]") Long[] ids) {
-            bookService.batchRemove(ids);
+        bookService.batchRemove(ids);
         return R.ok();
     }
 
+    /**
+     * 小说下载
+     */
+    @RequestMapping(value = "/download")
+    public void download(@RequestParam("bookId") Long bookId, @RequestParam("bookName") String bookName,
+        HttpServletResponse resp) {
+        try {
+            OutputStream out = resp.getOutputStream();
+            Boolean success = redisTemplate
+                .opsForValue()
+                .setIfAbsent(Constant.BOOK_IS_DOWNLOADING_KEY + bookId, "1", 10, TimeUnit.MINUTES);
+            if (Boolean.FALSE.equals(success)) {
+                resp.setContentType("text/html;charset=UTF-8");
+                out.write("该小说正在下载中，请稍后重试！".getBytes(StandardCharsets.UTF_8));
+                out.close();
+                return;
+            }
+            //设置响应头，对文件进行url编码
+            bookName = URLEncoder.encode(bookName, StandardCharsets.UTF_8);
+            //解决手机端不能下载附件的问题
+            resp.setContentType("application/octet-stream");
+            resp.setHeader("Content-Disposition", "attachment;filename=" + bookName + ".txt");
+
+            Map<String, Object> params = new HashMap<>();
+            params.put("bookId", bookId);
+            params.put("sort", "index_num");
+            params.put("order", "asc");
+            params.put("limit", 9999);
+            params.put("offset", 0);
+            List<BookIndexDO> bookIndexBigList = bookIndexService.list(params);
+            if (!bookIndexBigList.isEmpty()) {
+                List<List<BookIndexDO>> bookIndexSmallList = bookIndexBigList.stream().collect(
+                    Collectors.groupingBy(item -> bookIndexBigList.indexOf(item) / 100)).values().stream().toList();
+                for (List<BookIndexDO> bookIndexList : bookIndexSmallList) {
+                    // 获取集合中所有的ID
+                    List<Long> bookIndexIds = bookIndexList.stream().map(BookIndexDO::getId).toList();
+                    List<BookContentDO> bookContentList = bookContentService.listByIndexIds(bookIndexIds);
+                    Map<Long, String> bookContentMap = bookContentList.stream()
+                        .collect(Collectors.toMap(BookContentDO::getIndexId, BookContentDO::getContent));
+                    for (BookIndexDO bookIndex : bookIndexList) {
+                        String indexName = bookIndex.getIndexName();
+                        if (indexName != null) {
+                            String content = bookContentMap.get(bookIndex.getId());
+                            out.write(indexName.getBytes(StandardCharsets.UTF_8));
+                            out.write("\r\n".getBytes(StandardCharsets.UTF_8));
+                            content = PATTERN_BR.matcher(content).replaceAll("\r\n");
+                            content = PATTERN_NBSP.matcher(content).replaceAll(" ");
+                            content = PATTERN_ANCHOR_OPEN.matcher(content).replaceAll("");
+                            content = PATTERN_ANCHOR_CLOSE.matcher(content).replaceAll("");
+                            content = PATTERN_DIV_OPEN.matcher(content).replaceAll("");
+                            content = PATTERN_DIV_CLOSE.matcher(content).replaceAll("");
+                            content = PATTERN_EMPTY_PARAGRAPH_WITH_LINK.matcher(content).replaceAll("");
+                            content = PATTERN_P_OPEN.matcher(content).replaceAll("");
+                            content = PATTERN_P_CLOSE.matcher(content).replaceAll("\r\n");
+                            out.write(content.getBytes(StandardCharsets.UTF_8));
+                            out.write("\r\n".getBytes(StandardCharsets.UTF_8));
+                            out.write("\r\n".getBytes(StandardCharsets.UTF_8));
+                            out.flush();
+                        }
+                    }
+                }
+
+            }
+
+            out.close();
+
+
+        } catch (Exception e) {
+            log.error(e.getMessage(), e);
+        } finally {
+            redisTemplate.delete(Constant.BOOK_IS_DOWNLOADING_KEY + bookId);
+        }
+
+    }
+
 }

novel-admin/src/main/java/com/java2nb/novel/dao/BookContentDao.java

@@ -4,6 +4,7 @@ import com.java2nb.common.annotation.SanitizeMap;
 
 import com.java2nb.novel.domain.BookContentDO;
 import org.apache.ibatis.annotations.Mapper;
+import org.apache.ibatis.annotations.Param;
 
 import java.util.List;
 import java.util.Map;
@@ -33,4 +34,6 @@ public interface BookContentDao {
     int batchRemove(Long[] ids);
 
     int removeByIndexIds(Long[] indexIds);
+
+    List<BookContentDO> listByIndexIds(@Param("indexIds") List<Long> indexIds);
 }

novel-admin/src/main/java/com/java2nb/novel/service/BookContentService.java

@@ -27,4 +27,6 @@ public interface BookContentService {
 	int remove(Long id);
 	
 	int batchRemove(Long[] ids);
+
+    List<BookContentDO> listByIndexIds(List<Long> indexIds);
 }

novel-admin/src/main/java/com/java2nb/novel/service/impl/BookContentServiceImpl.java

@@ -1,5 +1,6 @@
 package com.java2nb.novel.service.impl;
 
+import org.apache.ibatis.annotations.Param;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
@@ -51,5 +52,10 @@ public class BookContentServiceImpl implements BookContentService {
 	public int batchRemove(Long[] ids){
 		return bookContentDao.batchRemove(ids);
 	}
-	
+
+	@Override
+	public List<BookContentDO> listByIndexIds(List<Long> indexIds) {
+		return bookContentDao.listByIndexIds(indexIds);
+	}
+
 }

novel-admin/src/main/resources/mybatis/novel/BookContentMapper.xml

@@ -38,6 +38,17 @@
         </where>
     </select>
 
+    <select id="listByIndexIds" resultType="com.java2nb.novel.domain.BookContentDO">
+        select `id`,`index_id`,`content` from book_content
+        where index_id in (
+        <foreach item="item" index="index" collection="indexIds" separator=",">
+            #{item}
+        </foreach>
+        )
+
+
+    </select>
+
     <insert id="save" parameterType="com.java2nb.novel.domain.BookContentDO">
         insert into book_content
         (`id`,

novel-admin/src/main/resources/static/js/appjs/novel/book/book.js

@@ -143,10 +143,14 @@ function load() {
                         field: 'id',
                         align: 'center',
                         formatter: function (value, row, index) {
+                            // 增加下载按钮
+                            var d = '<a class="btn btn-primary btn-sm" href="#" mce_href="#" title="下载TXT" onclick="downloadBook(\''
+                                + row.id
+                                + '\',\'' + row.bookName + '\')"><i class="fa fa-cloud-download"></i></a><br><br> ';
                             var r = '<a class="btn btn-warning btn-sm ' + s_remove_h + '" href="#" title="删除"  mce_href="#" onclick="remove(\''
                                 + row.id
                                 + '\')"><i class="fa fa-remove"></i></a> ';
-                            return r;
+                            return d + r;
                         }
                     }
 
@@ -249,4 +253,9 @@ function batchRemove() {
     }, function () {
 
     });
+}
+
+function downloadBook(bookId, bookName) {
+    window.open(prefix + '/download?bookId='+bookId+'&bookName='+bookName);
+
 }