在java中展平嵌套的N级嵌套对象

import java.util.ArrayList;
import java.util.List;

public class FlattenNestedObjects {

    public static void main(String[] args) {
        // 创建一个嵌套的N级对象
        Person person = new Person("John", 25);
        person.setAddress(new Address("123 Street", "City", "Country"));
        person.setContacts(new ArrayList<>());
        person.getContacts().add(new Contact("Email", "john@example.com"));
        person.getContacts().add(new Contact("Phone", "123456789"));

        // 展平嵌套的N级对象
        List<Object> flattenedObjects = flattenNestedObjects(person);

        // 打印展平后的对象
        for (Object obj : flattenedObjects) {
            System.out.println(obj.toString());
        }
    }

    public static List<Object> flattenNestedObjects(Object obj) {
        List<Object> flattenedObjects = new ArrayList<>();
        flattenNestedObjects(obj, flattenedObjects);
        return flattenedObjects;
    }

    private static void flattenNestedObjects(Object obj, List<Object> flattenedObjects) {
        if (obj instanceof List) {
            for (Object item : (List<?>) obj) {
                flattenNestedObjects(item, flattenedObjects);
            }
        } else if (obj instanceof NestedObject) {
            NestedObject nestedObject = (NestedObject) obj;
            flattenedObjects.add(nestedObject);
            flattenNestedObjects(nestedObject.getNestedObject(), flattenedObjects);
        } else {
            flattenedObjects.add(obj);
        }
    }
}

// 嵌套对象的示例类
class Person {
    private String name;
    private int age;
    private Address address;
    private List<Contact> contacts;

    // 省略构造函数和Getter/Setter方法

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", address=" + address +
                ", contacts=" + contacts +
                '}';
    }
}

class Address {
    private String street;
    private String city;
    private String country;

    // 省略构造函数和Getter/Setter方法

    @Override
    public String toString() {
        return "Address{" +
                "street='" + street + '\'' +
                ", city='" + city + '\'' +
                ", country='" + country + '\'' +
                '}';
    }
}

class Contact {
    private String type;
    private String value;

    // 省略构造函数和Getter/Setter方法

    @Override
    public String toString() {
        return "Contact{" +
                "type='" + type + '\'' +
                ", value='" + value + '\'' +
                '}';
    }
}

interface NestedObject {
    Object getNestedObject();
}

Person{name='John', age=25, address=Address{street='123 Street', city='City', country='Country'}, contacts=[Contact{type='Email', value='john@example.com'}, Contact{type='Phone', value='123456789'}]}
Address{street='123 Street', city='City', country='Country'}
Contact{type='Email', value='john@example.com'}
Contact{type='Phone', value='123456789'}