From 42b66729710967b8715b9f3c6d6ceed6029b385c Mon Sep 17 00:00:00 2001
From: duandazhi <ab601026460@163.com>
Date: Tue, 27 Sep 2022 09:37:27 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AD=97=E7=AC=A6=E4=B8=B2=E5=B7=A5=E5=85=B7?=
 =?UTF-8?q?=E7=B1=BB=EF=BC=9AsubStr=E5=A2=9E=E5=8A=A0=E6=B5=8B=E8=AF=95?=
 =?UTF-8?q?=E7=94=A8=E4=BE=8B=E3=80=81=E4=BB=A3=E7=A0=81=E7=A4=BA=E4=BE=8B?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../java/cn/hutool/core/text/CharSequenceUtil.java     |  9 +++++++++
 .../src/test/java/cn/hutool/core/text/StrUtilTest.java | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/hutool-core/src/main/java/cn/hutool/core/text/CharSequenceUtil.java b/hutool-core/src/main/java/cn/hutool/core/text/CharSequenceUtil.java
index ffd27977f..e217b9f09 100755
--- a/hutool-core/src/main/java/cn/hutool/core/text/CharSequenceUtil.java
+++ b/hutool-core/src/main/java/cn/hutool/core/text/CharSequenceUtil.java
@@ -1741,6 +1741,15 @@ public class CharSequenceUtil extends StrChecker {
 
 	/**
 	 * 切割指定位置之前部分的字符串
+	 * <p>安全的subString,允许：string为null，允许string长度小于toIndexExclude长度</p>
+	 * <pre>
+	 *      Assert.assertEquals(StrUtil.subPre(null, 3), null);
+	 * 		Assert.assertEquals(StrUtil.subPre("ab", 3), "ab");
+	 * 		Assert.assertEquals(StrUtil.subPre("abc", 3), "abc");
+	 * 		Assert.assertEquals(StrUtil.subPre("abcd", 3), "abc");
+	 * 		Assert.assertEquals(StrUtil.subPre("abcd", -3), "a");
+	 * 		Assert.assertEquals(StrUtil.subPre("ab", 3), "ab");
+	 * </pre>
 	 *
 	 * @param string         字符串
 	 * @param toIndexExclude 切割到的位置（不包括）
diff --git a/hutool-core/src/test/java/cn/hutool/core/text/StrUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/text/StrUtilTest.java
index 0e868f6ce..7f380e5b7 100644
--- a/hutool-core/src/test/java/cn/hutool/core/text/StrUtilTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/text/StrUtilTest.java
@@ -280,6 +280,16 @@ public class StrUtilTest {
 		Assert.assertEquals("ghigh", pre);
 	}
 
+	@Test
+	public void subPreTest() {
+		Assert.assertEquals(StrUtil.subPre(null, 3), null);
+		Assert.assertEquals(StrUtil.subPre("ab", 3), "ab");
+		Assert.assertEquals(StrUtil.subPre("abc", 3), "abc");
+		Assert.assertEquals(StrUtil.subPre("abcd", 3), "abc");
+		Assert.assertEquals(StrUtil.subPre("abcd", -3), "a");
+		Assert.assertEquals(StrUtil.subPre("ab", 3), "ab");
+	}
+
 	@Test
 	public void subByCodePointTest() {
 		// 🤔👍🍓🤔