修复ClassUtil.getTypeArgument() 获取泛型存在null问题

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

@@ -343,8 +343,9 @@ public class TypeUtil {
 		final Type[] genericInterfaces = clazz.getGenericInterfaces();
 		if (ArrayUtil.isNotEmpty(genericInterfaces)) {
 			for (final Type genericInterface : genericInterfaces) {
-				if (genericInterface instanceof ParameterizedType) {
+				final ParameterizedType parameterizedType = toParameterizedType(genericInterface);
-					result.add((ParameterizedType) genericInterface);
+				if(null != parameterizedType){
+					result.add(parameterizedType);
 				}
 			}
 		}

hutool-core/src/test/java/org/dromara/hutool/core/reflect/Issue3516Test.java

@@ -0,0 +1,34 @@
+package org.dromara.hutool.core.reflect;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Type;
+import java.util.function.Function;
+
+public class Issue3516Test {
+
+	@Test
+	public void getTypeArgumentTest() {
+		final Type typeArgument = TypeUtil.getTypeArgument(Demo.class, 0);
+		Assertions.assertEquals(B.class, typeArgument);
+	}
+
+	static class Demo implements A2B{
+		@Override
+		public A apply(final B b) {
+			return new A();
+		}
+	}
+
+	static class A {
+		private String name;
+	}
+
+	static class B {
+		private String name;
+	}
+
+	interface A2B extends Function<B, A> {
+	}
+}