From 06e136f3112002dd3149c339643e37f626e6980f Mon Sep 17 00:00:00 2001
From: Looly <loolly@gmail.com>
Date: Sun, 11 Jul 2021 18:07:56 +0800
Subject: [PATCH] add methods

---
 CHANGELOG.md                                  |  1 +
 .../cn/hutool/core/collection/CollUtil.java   | 24 +++++++++++++++++++
 .../core/io/FastByteArrayOutputStream.java    |  6 ++++-
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4bbf1dd54..9110025bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@
 * 【setting】     修复Props中Charset对象无法序列化的问题（pr#1694@Github）
 * 【db     】     修复PageResult首页判断逻辑问题（issue#1699@Github）
 * 【core   】     修复IdcardUtil可能数组越界问题（pr#1702@Github）
+* 【core   】     修复FastByteArrayOutputStream索引越界问题（issue#I402ZP@Github）
 
 -------------------------------------------------------------------------------------------------------------
 
diff --git a/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java b/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
index 5f283eb5b..417f3a152 100644
--- a/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/collection/CollUtil.java
@@ -1602,6 +1602,18 @@ public class CollUtil {
 		return null == enumeration || false == enumeration.hasMoreElements();
 	}
 
+	/**
+	 * Map是否为空
+	 *
+	 * @param map 集合
+	 * @return 是否为空
+	 * @see MapUtil#isEmpty(Map)
+	 * @since 5.7.4
+	 */
+	public static boolean isEmpty(Map<?, ?> map) {
+		return MapUtil.isEmpty(map);
+	}
+
 	// ---------------------------------------------------------------------- isNotEmpty
 
 	/**
@@ -1658,6 +1670,18 @@ public class CollUtil {
 		return IterUtil.hasNull(iterable);
 	}
 
+	/**
+	 * Map是否为非空
+	 *
+	 * @param map 集合
+	 * @return 是否为非空
+	 * @see MapUtil#isNotEmpty(Map)
+	 * @since 5.7.4
+	 */
+	public static boolean isNotEmpty(Map<?, ?> map) {
+		return MapUtil.isNotEmpty(map);
+	}
+
 	// ---------------------------------------------------------------------- zip
 
 	/**
diff --git a/hutool-core/src/main/java/cn/hutool/core/io/FastByteArrayOutputStream.java b/hutool-core/src/main/java/cn/hutool/core/io/FastByteArrayOutputStream.java
index 43d6cf20a..16bfda8fc 100644
--- a/hutool-core/src/main/java/cn/hutool/core/io/FastByteArrayOutputStream.java
+++ b/hutool-core/src/main/java/cn/hutool/core/io/FastByteArrayOutputStream.java
@@ -68,6 +68,10 @@ public class FastByteArrayOutputStream extends OutputStream {
 	 */
 	public void writeTo(OutputStream out) throws IORuntimeException {
 		final int index = buffer.index();
+		if(index < 0){
+			// 无数据写出
+			return;
+		}
 		byte[] buf;
 		try {
 			for (int i = 0; i < index; i++) {
@@ -113,4 +117,4 @@ public class FastByteArrayOutputStream extends OutputStream {
 				ObjectUtil.defaultIfNull(charset, CharsetUtil.defaultCharset()));
 	}
 
-}
\ No newline at end of file
+}