将字符串转换为对象

when I create an object of the class BinaryTreeNode , I want to pass two String in the Constructor rather than an object of the class BinaryTreeNode how can I do that.

当我创建BinaryTreeNode类的对象时,我想在构造函数中传递两个String而不是BinaryTreeNode类的对象,我该怎么做呢。

        BinaryTreeNode(BinaryTreeNode left,BinaryTreeNode right) {
        this.left = left;
        this.right = right;
    }


BinaryTreeNode b  = new BinaryTreeNode("B","A");

2 个解决方案

#1

Write another constructor that takes two String parameters.

编写另一个带有两个String参数的构造函数。

    BinaryTreeNode(String left, String right) {
        //whose knows why I want to do this...
    }

You can't cast a String into a BinaryTreeNode, that would throw an Exception.

您不能将String强制转换为BinaryTreeNode,否则会抛出异常。

#2

It is not possible to cast any object to a type which it is not.

不可能将任何对象转换为不是的类型。

But that is fine, and I suspect it is not the root of the problem, because it doesn't make sense to treat a String object as a BinaryTreeNode - they have naught in common except that which they both inherit from Object.

但这很好,我怀疑它不是问题的根源,因为将String对象视为BinaryTreeNode是没有意义的 - 除了它们都从Object继承之外它们没有共同之处。

Thus, I would either make the "node/leaf value" part of the BinaryTreeNode type or, I may introduce a leaf node type such as:

因此,我要么将“节点/叶子值”作为BinaryTreeNode类型的一部分,或者我可能会引入叶节点类型,例如:

class BinaryTreeLeafNode extends BinaryTreeNode {
    public final String value;

    public BinaryTreeLeafNode (String value) {
        super(null, null); // got anything better? :|
        this.value = value;
    }
}

Then:

tree = new BinaryTreeNode(
    new BinaryTreeLeafNode("Left"),
    new BinaryTreeLeafNode("Right"));

And perhaps if I wanted to hide the details, then an overload could be introduced:

也许如果我想隐藏细节,可能会引入过载:

public BinaryTreeNode (String leftValue, String rightValue) {
    this(new BinaryTreeLeafNode(leftValue), new BinaryTreeLeafNode(rightValue));
}

(I would advise against widening the left/right member and constructor types to to Object, as that will eliminate a good bit of type-safety.)

(我建议不要将左/右成员和构造函数类型扩展为Object,因为这将消除一些类型安全性。)

#1