如何投射不互相继承的对象? [英] How can I cast objects that don't inherit each other?

问题描述

我有2个不同的类，它们具有不同的字段，而一个类具有这两个类的所有字段.有什么方法可以将对象投射到两个单独的对象中?

I have 2 different classes with different fields and a class which has all the fields of both classes. Is there any way to cast the object in to two separate objects?

class A{
    private int a;
    private int b;
}

class B{ 
    private int a;
    private int b;
}

如果对象 D 具有A和B类的所有属性，是否有办法分别转换它们?

If object D have all the properties of A and B classes, Is there any way to cast them separately?

推荐答案

从孩子到父母的铸造(垂头丧气)，反之亦然(铸造):

Casting take place from child to parent (downcast) or vise versa (upcast):

class A extends B
B b = (B)(new A());

，或者在使用接口的情况下:

or in case of interfaces:

List<String> myList = new ArrayList<>();
ArrayList<String> myArrayList = (ArrayList)myList;

投放时要小心-如果无法投放，则会收到 Exception ！

Be careful when casting - if casting is not possible, you'll receive Exception!

在您的情况下，映射是您要寻找的.您只需要一个映射器.

In your case, mapping is what you're looking for. You simply need a mapper.

例如:

public class AToBMapper {
    public static A fromB(B b) {
        A a = new A();
        a.setA(b.getA());
        a.setB(b.getB());
        return a;
    }

    public static B fromA(A a) {
        //fill in
    }
}

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