fix：ReUtil.replaceAll()方法，当replacementTemplate为null对象时，出现空指针异常

hutool-core/src/main/java/cn/hutool/core/regex/ReUtil.java

@@ -876,6 +876,9 @@ public class ReUtil {
 			return StrUtil.str(content);
 		}
 
+		// replacementTemplate字段不能为null，否则无法抉择如何处理结果
+		Assert.notNull(replacementTemplate, "ReplacementTemplate must be not null !");
+
 		final Matcher matcher = pattern.matcher(content);
 		boolean result = matcher.find();
 		if (result) {

hutool-core/src/test/java/cn/hutool/core/util/ReUtilTest.java

@@ -115,6 +115,16 @@ public class ReUtilTest {
 		Assert.assertEquals("ZZZaaabbbccc中文->1234<-", replaceAll);
 	}
 
+	@Test
+	public void replaceAllTest3() {
+		// 修改前：ReUtil.replaceAll()方法，当replacementTemplate为null对象时，出现空指针异常
+		final String str = null;
+		// Assert.assertThrows(NullPointerException.class, () -> ReUtil.replaceAll(content, "(\\d+)", str));
+
+		// 修改后：判断ReUtil.replaceAll()方法，当replacementTemplate为null对象时，提示为非法的参数异常：ReplacementTemplate must be not null !
+		Assert.assertThrows(IllegalArgumentException.class, () -> ReUtil.replaceAll(content, "(\\d+)", str));
+	}
+
 	@Test
 	public void replaceTest() {
 		final String str = "AAABBCCCBBDDDBB";