修复JsonUtil.toBean泛型数组类型丢失问题（pr#3876@Github）

hutool-core/src/main/java/org/dromara/hutool/core/reflect/TypeUtil.java

@@ -418,7 +418,7 @@ public class TypeUtil {
 	 *     2. 泛型变量，类似于T
 	 * </pre>
 	 *
-	 * @param type         类
+	 * @param type         泛型类
 	 * @param typeVariable 泛型变量，例如T等
 	 * @return 实际类型，可能为Class等
 	 */
@@ -431,7 +431,10 @@ public class TypeUtil {
 		}
 		// pr#3876 解决泛型数组泛型类型无法识别问题
 		if (typeVariable instanceof GenericArrayType) {
-			return ActualTypeMapperPool.getActualType(type, (GenericArrayType) typeVariable);
+			final Type actualType = ActualTypeMapperPool.getActualType(type, (GenericArrayType) typeVariable);
+			if(null != actualType){
+				return actualType;
+			}
 		}
 
 		// 没有需要替换的泛型变量，原样输出

hutool-core/src/test/java/org/dromara/hutool/core/reflect/ClassUtilTest.java

@@ -30,6 +30,11 @@ import java.util.Objects;
  */
 class ClassUtilTest {
 
+	@Test
+	void forNameTest() {
+		Assertions.assertEquals(String.class, ClassUtil.forName("java.lang.String", false, null));
+	}
+
 	@Test
 	void testGetSuperClasses() {
 		// if root is null

hutool-json/src/test/java/org/dromara/hutool/json/issues/Issue3504Test.java

@@ -42,6 +42,8 @@ public class Issue3504Test {
 		jsonBean.setClasses(new Class[]{String.class});
 
 		final String jsonStr = JSONUtil.toJsonStr(jsonBean);
+		Assertions.assertEquals("{\"name\":\"test\",\"classes\":[\"java.lang.String\"]}", jsonStr);
+
 		final JsonBean bean = JSONUtil.toBean(jsonStr, JsonBean.class);
 		Assertions.assertNotNull(bean);
 		Assertions.assertEquals("test", bean.getName());