Question

我正在用Java编写二十一点程序，在学习使用内部类时我遇到了一个问题。我尝试在其自身内部实例化Blackjack对象以调用内部类Card的方法，但程序找不到Blackjack类。我怎么能解决这个问题：

import java.util.Scanner;
import java.util.Deque;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;

public class Blackjack {

    int playerWins = 0, dealerWins = 0;

    // Inner Class - private for encapsulation
    private class Card {
        private int suit;
        private int value;

        private Card(int suit, int value) {
            this.suit = suit;
            this.value = value;
        }

        private int getValue() {
            return value;
        }

        private int getSuit() {
            return suit;
        }
    }

    public static void main(String[] args) {
        Deque<Card> deck = new ArrayDeque<Card>();
        Deque<Card> player = new ArrayDeque<Card>();
        Deque<Card> dealer = new ArrayDeque<Card>();
        Blackjack game = new Blackjack();
        game.createDeck(deck); // Create deck
        game.shuffle(deck);// Shuffle
        game.play(deck,player,dealer);// Deal
    }
    ...

我在尝试编译时遇到的错误：

Exception in thread "main" java.lang.ClassNotFoundException: Blackjack
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:122)

Answer 1

我已经实现了createDeck，shuffle，play方法，并且该类正确地工作。代码如下：

import java.util.Deque;
import java.util.ArrayDeque;

public class Blackjack {

    int playerWins = 0, dealerWins = 0;

    private void createDeck(Deque<Card> deck) {
        System.out.println("createDeck");
    }

    private void shuffle(Deque<Card> deck) {
        System.out.println("shuffle");
    }

    private void play(Deque<Card> deck, Deque<Card> player, Deque<Card> dealer) {
        System.out.println("play");
    }

    // Inner Class - private for encapsulation
    private class Card {

        private int suit;
        private int value;

        private Card(int suit, int value) {
            this.suit = suit;
            this.value = value;
        }

        private int getValue() {
            return value;
        }

        private int getSuit() {
            return suit;
        }
    }

    public static void main(String[] args) {
        Deque<Card> deck = new ArrayDeque<Card>();
        Deque<Card> player = new ArrayDeque<Card>();
        Deque<Card> dealer = new ArrayDeque<Card>();
        Blackjack game = new Blackjack();
        game.createDeck(deck);
        game.shuffle(deck);
        game.play(deck, player, dealer);
    }

}

编辑：

查看您的错误，也许Blackjack类的文件夹不在类路径中。如果从包含的文件夹中启动该类，则必须设置＆＃34;。＆＃34;类路径中的文件夹。

无法在其内部实例化类

1 个答案: