java - this(<params>) 作为构造函数中的快捷方式？

Question

我有一项任务需要减少构造函数中的代码，但是当我按照给定示例执行时它不起作用:(

源代码看起来是这样的:

public class Item {
    private Product product;
    private int stock;

    Item(Product product){
        this.product=product;
        this.stock=0;
    }

    Item(Product product, int stock){
        this.product=product;
        this.stock=stock;
    }

我试着这样写:

    public class Item {
        private Product product;
        private int stock;

        Item(Product product){
            this(product, 0);
        }

        Item(Product product, int stock){
            this(product, stock);
        }

谁能告诉我哪里出了问题？

Answer 1

第二个构造函数中有一个循环引用，它正在调用自己。试试这个:

// this constructor is correctly defined
public Item(Product product, int stock) {
    this.product = product;
    this.stock   = stock;
}

// this constructor calls the other one
public Item(Product product) {
    this(product, 0);
}