Java 反射获取类的属性和父类的属性

定义两个类Person是父类，Student是子类

public class Person {
    private String username;
    private String grade;
}

public class Student extends Person {
    private String sex;
}

通过反射分别获取父类和子类的属性

public class ReflectTest {
    public static void main(String[] args) throws Exception {
        Field[] declaredFields = Person.class.getDeclaredFields();
        for (Field f : declaredFields) {
            System.out.println("父类的属性:" + f.getName());
        }
        System.out.println("--------------");
        Field[] declaredFields1 = Student.class.getDeclaredFields();
        for (Field f : declaredFields1) {
            System.out.println("子类的属性:" + f.getName());
        }
        System.out.println("---------");
    }

如果想要通过属性名去获取类的属性

 Field f=Student.class.getDeclaredField("sex");

如果想要通过子类获取父类的所有属性

/**
 *
 * 反射通过子类遍历父类的属性
 *
 */
        Class clazz = Student.class;
        List fieldsList = new ArrayList<Field>();
        while (clazz != null) {  // 遍历所有父类字节码对象
            Field[] declaredFields2 = clazz.getDeclaredFields();
            fieldsList.addAll(Arrays.asList(declaredFields2));  //将`Filed[]`数组转换为`List<>`然后再将其拼接至`ArrayList`上
            clazz = clazz.getSuperclass();  // 获得父类的字节码对象
        }
        for (Object field : fieldsList) {  // 打印当前类以及其父类的多有属性对象
            System.out.println(field);
        }

如果子类没有的属性从父类获取

public class ReflectTest2 {
    public static void main(String[] args) {
        Student student = new Student();
        Field username = null;
            username = getDeclareField(student, "username");
        System.out.println(username);
    }

    public static Field getDeclareField(Object o, String fieldName)  {
        Field field = null;
        Class<?> clazz = o.getClass();
        System.out.println(clazz != Object.class);
        for (;field==null; clazz = clazz.getSuperclass()) {
            try {
                field = clazz.getDeclaredField(fieldName);
            } catch (NoSuchFieldException e) {
                //e.printStackTrace();
            }
        }
        return field;
    }
}

参考：https://blog.youkuaiyun.com/weixin_38167855/article/details/99648823