From a9bd7c3bb414093de2d316454866b4b69b2fa531 Mon Sep 17 00:00:00 2001
From: looly <loolly@gmail.com>
Date: Sun, 12 Dec 2021 09:58:43 +0800
Subject: [PATCH] fix line bug

---
 CHANGELOG.md                                                | 3 ++-
 .../main/java/cn/hutool/core/io/file/LineReadWatcher.java   | 4 ++--
 .../src/test/java/cn/hutool/core/io/file/TailerTest.java    | 6 +++---
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5733079e3..4b942835d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,10 +3,11 @@
 
 -------------------------------------------------------------------------------------------------------------
 
-# 5.7.18 (2021-12-09)
+# 5.7.18 (2021-12-12)
 
 ### 🐣新特性
 ### 🐞Bug修复
+* 【core   】     LineReadWatcher#onModify文件清空判断问题（issue#2013@Github）
 
 -------------------------------------------------------------------------------------------------------------
 # 5.7.17 (2021-12-09)
diff --git a/hutool-core/src/main/java/cn/hutool/core/io/file/LineReadWatcher.java b/hutool-core/src/main/java/cn/hutool/core/io/file/LineReadWatcher.java
index 7178e665f..1c9e50043 100644
--- a/hutool-core/src/main/java/cn/hutool/core/io/file/LineReadWatcher.java
+++ b/hutool-core/src/main/java/cn/hutool/core/io/file/LineReadWatcher.java
@@ -50,11 +50,11 @@ public class LineReadWatcher extends SimpleWatcher implements Runnable {
 		try {
 			final long currentLength = randomAccessFile.length();
 			final long position = randomAccessFile.getFilePointer();
-			if (0 == currentLength || position == currentLength) {
+			if (position == currentLength) {
 				// 内容长度不变时忽略此次事件
 				return;
 			} else if (currentLength < position) {
-				// 如果内容变短，说明文件做了删改，回到内容末尾
+				// 如果内容变短或变0，说明文件做了删改或清空，回到内容末尾或0
 				randomAccessFile.seek(currentLength);
 				return;
 			}
diff --git a/hutool-core/src/test/java/cn/hutool/core/io/file/TailerTest.java b/hutool-core/src/test/java/cn/hutool/core/io/file/TailerTest.java
index 584186003..de2bedd48 100644
--- a/hutool-core/src/test/java/cn/hutool/core/io/file/TailerTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/io/file/TailerTest.java
@@ -7,13 +7,13 @@ import cn.hutool.core.io.FileUtil;
 import cn.hutool.core.util.CharsetUtil;
 
 public class TailerTest {
-	
+
 	@Test
 	@Ignore
 	public void tailTest() {
-		FileUtil.tail(FileUtil.file("e:/tail.txt"), CharsetUtil.CHARSET_GBK);
+		FileUtil.tail(FileUtil.file("d:/test/tail.txt"), CharsetUtil.CHARSET_GBK);
 	}
-	
+
 	@Test
 	@Ignore
 	public void tailWithLinesTest() {