From 3ec1b3745da783232760cf15f8967a1262180d13 Mon Sep 17 00:00:00 2001
From: Looly <loolly@aliyun.com>
Date: Tue, 18 Feb 2025 19:01:52 +0800
Subject: [PATCH] =?UTF-8?q?`FileWriter`=E5=A2=9E=E5=8A=A0=E6=96=B9?=
 =?UTF-8?q?=E6=B3=95=EF=BC=8C=E5=8F=AF=E9=80=89=E6=98=AF=E5=90=A6=E8=BF=BD?=
 =?UTF-8?q?=E5=8A=A0=E6=8D=A2=E8=A1=8C=E7=AC=A6=EF=BC=88issue#3858@Github?=
 =?UTF-8?q?=EF=BC=89?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../hutool/core/io/file/FileWriter.java       | 11 +++++-----
 .../hutool/core/io/file/FileWriterTest.java   | 21 +++++++++++++++++++
 2 files changed, 26 insertions(+), 6 deletions(-)
 create mode 100644 hutool-core/src/test/java/org/dromara/hutool/core/io/file/FileWriterTest.java

diff --git a/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileWriter.java b/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileWriter.java
index c3af771f7..5845ba29c 100644
--- a/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileWriter.java
+++ b/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileWriter.java
@@ -204,7 +204,7 @@ public class FileWriter extends FileWrapper {
 	 * @since 3.1.0
 	 */
 	public <T> File writeLines(final Iterable<T> list, final LineSeparator lineSeparator, final boolean isAppend) throws IORuntimeException {
-		return writeLines(list, lineSeparator, isAppend, false);
+		return writeLines(list, lineSeparator, isAppend, true);
 	}
 
 	/**
@@ -234,13 +234,12 @@ public class FileWriter extends FileWrapper {
 						printNewLine(writer, lineSeparator);
 					}
 					writer.print(t);
-					if(appendLineSeparator){
-						printNewLine(writer, lineSeparator);
-					}
-
-					writer.flush();
 				}
 			}
+			if(appendLineSeparator){
+				printNewLine(writer, lineSeparator);
+			}
+			writer.flush();
 		}
 		return this.file;
 	}
diff --git a/hutool-core/src/test/java/org/dromara/hutool/core/io/file/FileWriterTest.java b/hutool-core/src/test/java/org/dromara/hutool/core/io/file/FileWriterTest.java
new file mode 100644
index 000000000..aacce41a3
--- /dev/null
+++ b/hutool-core/src/test/java/org/dromara/hutool/core/io/file/FileWriterTest.java
@@ -0,0 +1,21 @@
+package org.dromara.hutool.core.io.file;
+
+import org.dromara.hutool.core.collection.ListUtil;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+public class FileWriterTest {
+	@Test
+	@Disabled
+	void writeLinesAppendLineSeparatorTest() {
+		final FileWriter writer = FileWriter.of(FileUtil.file("d:/test/lines_append_line_separator.txt"));
+		writer.writeLines(ListUtil.of("aaa", "bbb", "ccc"), null, false);
+	}
+
+	@Test
+	@Disabled
+	void writeLinesTest() {
+		final FileWriter writer = FileWriter.of(FileUtil.file("d:/test/lines.txt"));
+		writer.writeLines(ListUtil.of("aaa", "bbb", "ccc"), null, false, false);
+	}
+}