修复BeanUtil.copyProperties中mapToMap时key被转为String问题

hutool-core/src/test/java/cn/hutool/core/bean/Issue3645Test.java

@@ -0,0 +1,30 @@
+package cn.hutool.core.bean;
+
+import lombok.Data;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.Assert.assertNotNull;
+
+public class Issue3645Test {
+	@Test
+	public void copyPropertiesTest() {
+		User p = new User();
+		p.setUserId(123L);
+
+		Map<Long, User> map = new HashMap<>();
+		map.put(123L,p);
+
+		Map<Long, User> m = new HashMap<>();
+		BeanUtil.copyProperties(map, m);
+		User u = m.get(123L);
+		assertNotNull(u);
+	}
+
+	@Data
+	static class User{
+		private Long userId;
+	}
+}