如何在Java中访问对象的父对象？

Question

看一下这个例子：

class Parent{
    Child child = new Child();
    Random r = new Random();
}

class Child{

    public Child(){
        //access a method from Random r from here without creating a new Random()
    }
}

如何从子对象中访问随机对象？

Answer 1

让Parent类将自己的实例传递Random给Child该类。

class Parent{
    Child child;
    Random r = new Random();

    public Parent()
    {
        child = new Child(r);
    }
}

class Child{    
    public Child(Random r){

    }    
}

经典Occam剃刀。