From 32a5ff53b640ee1f4659c91fc9028edeb5db42a2 Mon Sep 17 00:00:00 2001
From: zwm <2076229520@qq.com>
Date: Fri, 29 Aug 2025 02:36:01 +0800
Subject: [PATCH] Fix issue 4040

---
 .../main/java/cn/hutool/db/sql/Condition.java | 27 +++++++++++++++----
 .../java/cn/hutool/db/sql/ConditionTest.java  |  9 +++++++
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/hutool-db/src/main/java/cn/hutool/db/sql/Condition.java b/hutool-db/src/main/java/cn/hutool/db/sql/Condition.java
index cfbfcc251d..c87b5d406b 100644
--- a/hutool-db/src/main/java/cn/hutool/db/sql/Condition.java
+++ b/hutool-db/src/main/java/cn/hutool/db/sql/Condition.java
@@ -257,6 +257,17 @@ public class Condition extends CloneSupport<Condition> {
 		return OPERATOR_IS.equalsIgnoreCase(this.operator);
 	}
 
+	/**
+	 * 是否 IS NOT条件
+	 *
+	 * @return 是否IS NOT条件
+	 * @since 5.8.0
+	 */
+	public boolean isOperatorIsNot() {
+		return OPERATOR_IS_NOT.equalsIgnoreCase(this.operator);
+	}
+
+
 	/**
 	 * 是否LIKE条件
 	 *
@@ -268,18 +279,24 @@ public class Condition extends CloneSupport<Condition> {
 	}
 
 	/**
-	 * 检查值是否为null，如果为null转换为 "IS NULL"形式
+	 * 检查值是否为null，如果为null转换为 "IS NULL"或"IS NOT NULL"形式
 	 *
 	 * @return this
 	 */
 	public Condition checkValueNull() {
 		if (null == this.value) {
-			this.operator = OPERATOR_IS;
+			// 检查是否为"不等于"操作符（包括!=和<>）
+			if ("!=".equalsIgnoreCase(this.operator) || "<>".equalsIgnoreCase(this.operator)) {
+				this.operator = OPERATOR_IS_NOT;
+			} else {
+				this.operator = OPERATOR_IS;
+			}
 			this.value = VALUE_NULL;
 		}
 		return this;
 	}
 
+
 	/**
 	 * 获得between 类型中第二个值
 	 *
@@ -345,8 +362,8 @@ public class Condition extends CloneSupport<Condition> {
 			// 类似：" (?,?,?)" 或者 " (1,2,3,4)"
 			buildValuePartForIN(conditionStrBuilder, paramValues);
 		} else {
-			if (isPlaceHolder() && false == isOperatorIs()) {
-				// 使用条件表达式占位符，条件表达式并不适用于 IS NULL
+			if (isPlaceHolder() && !isOperatorIs() && !isOperatorIsNot()) {
+				// 使用条件表达式占位符，条件表达式并不适用于 IS NULL 和 IS NOT NULL
 				conditionStrBuilder.append(" ?");
 				if (null != paramValues) {
 					paramValues.add(this.value);
@@ -355,7 +372,7 @@ public class Condition extends CloneSupport<Condition> {
 				// 直接使用条件值
 				final String valueStr = String.valueOf(this.value);
 				conditionStrBuilder.append(" ").append(isOperatorLike() ?
-						StrUtil.wrap(valueStr, "'") : valueStr);
+					StrUtil.wrap(valueStr, "'") : valueStr);
 			}
 		}
 
diff --git a/hutool-db/src/test/java/cn/hutool/db/sql/ConditionTest.java b/hutool-db/src/test/java/cn/hutool/db/sql/ConditionTest.java
index 2b71081708..fbf5064206 100644
--- a/hutool-db/src/test/java/cn/hutool/db/sql/ConditionTest.java
+++ b/hutool-db/src/test/java/cn/hutool/db/sql/ConditionTest.java
@@ -12,9 +12,18 @@ public class ConditionTest {
 		Condition conditionNull = new Condition("user", null);
 		assertEquals("user IS NULL", conditionNull.toString());
 
+		Condition conditionNull2 = new Condition("user", "=", (String) null);
+		assertEquals("user IS NULL", conditionNull2.toString());
+
 		Condition conditionNotNull = new Condition("user", "!= null");
 		assertEquals("user IS NOT NULL", conditionNotNull.toString());
 
+		Condition conditionNotNull2 = new Condition("user", "!=", (String) null);
+		assertEquals("user IS NOT NULL", conditionNotNull2.toString());
+
+		Condition conditionNotNull3 = new Condition("user", "<>", (String) null);
+		assertEquals("user IS NOT NULL", conditionNotNull3.toString());
+
 		Condition condition2 = new Condition("user", "= zhangsan");
 		assertEquals("user = ?", condition2.toString());