java - 两个 java.lang.NullPointerException 错误

Question

我实际上收到了三个 java.langNullPointerException 错误，但其中两个是相同的，因此如果我修复一个错误，我就会修复另一个错误。

我正在尝试创建一个游戏类来通过游戏测试

这是我的游戏类的代码

public class Game implements CribbageConstants {

    private Player player1, player2;
    private boolean player1Deals;
    private Game game;

    /**
     * No argument constructor - set default values for Game
     */
    public Game() {
        player1 = player1;
        player1 = player2;
        player1Deals = true;



    }

    // convenience constructor
    public Game(Player player1, Player player2) {
        this.player1 = player1;
        this.player2 = player2;
        this.player1Deals = true;

    }

    //mutator
    public void setPlayer1(Player player1) {
        this.player1 = player1;

    }

    public void setPlayer2(Player player2) {
        this.player2 = player2;
    }

    public void setPlayer1Deals(boolean player1Deals) {
        this.player1Deals = player1Deals;
    }

    public void setGame(Game game) {
        this.game = game;
    }

    //utility methods
    public Player getPlayer1() {
        return player1;
    }

    public Player getPlayer2() {
        return player2;
    }

    /**
     * @return the player1Deals
     */
    public boolean isPlayer1Deals() {
        return player1Deals;
    }

    /**
     * @return the game
     */
    public Game getGame() {
        return game;
    }
}

我在以下代码的第 86 行收到一个 NullPointerException:

//79    public void testSetPlayer1() {
//80        System.out.println("setPlayer1");
//81        Game instance = new Game();
//82        Player p1 = new Player("Jim");
//83        p1.setHand(hand1);
//84        Player p2 = new Player("George");
//85        p2.setHand(hand2);
//86        assertEquals("?", instance.getPlayer1().getName());
//87        instance.setPlayer1(p1);
//88        assertEquals("Jim", instance.getPlayer1().getName());
    }

我在 testNoArgConstructor 上遇到一个 NullPointerException(第 54 行)

//51    public void testNoArgConstructor() {
//52       System.out.println("Game");
//53       Game instance = new Game();
//54       assertEquals("?", instance.getPlayer1().getName());
//55       assertEquals("?", instance.getPlayer2().getName());
//56       assertEquals(true, instance.isPlayer1Deals());
//57   }

Answer 1

您没有在 instance.getPlayer()` 之前设置变量 player1

//79    public void testSetPlayer1() {
//80        System.out.println("setPlayer1");
//81        Game instance = new Game();
//82        Player p1 = new Player("Jim");

            instance.setPlayer1(p1);

//83        p1.setHand(hand1);
//84        Player p2 = new Player("George");
//85        p2.setHand(hand2);
//86        assertEquals("?", instance.getPlayer1().getName());
//87        instance.setPlayer1(p1);
//88        assertEquals("Jim", instance.getPlayer1().getName());
    }

在这两种情况下您都遇到同样的问题。

//51    public void testNoArgConstructor() {
//52       System.out.println("Game");
//53       Game instance = new Game();

           instance.setPlayer1(new Player("Player One");
//54       assertEquals("?", instance.getPlayer1().getName());

           instance.setPlayer2(new Player("Player Two");
//55       assertEquals("?", instance.getPlayer2().getName());
//56       assertEquals(true, instance.isPlayer1Deals());
//57   }

如果您无法编辑测试用例，您可以尝试使用Game中变量的默认值

public Game() {
        player1 = new Player("?");
        player1 = new Player("?");
        player1Deals = true;



    }