diff --git a/app/src/main/java/com/kunfei/bookshelf/help/BookshelfHelp.java b/app/src/main/java/com/kunfei/bookshelf/help/BookshelfHelp.java
index 7c7f37060d..b9ae01dd4c 100644
--- a/app/src/main/java/com/kunfei/bookshelf/help/BookshelfHelp.java
+++ b/app/src/main/java/com/kunfei/bookshelf/help/BookshelfHelp.java
@@ -40,7 +40,7 @@
 
 public class BookshelfHelp {
 
-    private static Pattern chapterNamePattern = Pattern.compile("^(.*?第([\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟０-９\\s]+)[章节篇回集])[、，。　：:.\\s]*");
+    private static final Pattern chapterNamePattern = Pattern.compile("^(.*?第([\\d零〇一二两三四五六七八九十百千万壹贰叁肆伍陆柒捌玖拾佰仟０-９\\s]+)[章节篇回集])[、，。　：:.\\s]*");
 
     public static String getCachePathName(String bookName, String tag) {
         return formatFolderName(bookName + "-" + tag);