java - 在 Java 中使用 HashMap

Question

基本上，我正在 BlueJ 中制作这个 Java 程序，其中玩家处于指环王的世界中。我为武器、元素等创建了单独的包。我在所有包之外(在项目屏幕的主体中)有一个 Main 类。在那里，我尝试了一些东西。

public static void test()throws Exception{
        System.out.println("There is a brass sword and an iron sword. Which do you want?");
        Scanner in = new Scanner(System.in);
        String s = in.next();
        HashMap options = new HashMap();
        options.put("brass", new Sword());
        options.put("iron", new Sword());
        Sword k = options.get(s);
}

我希望上面的方法返回一个 Sword 对象给我。不幸的是，这不起作用。有什么帮助吗......？

Answer 1

只需使用参数化类型HashMap，将HashMap声明为

HashMap<String, Sword> options = new HashMap<String, Sword>();

I want the above method to return a Sword object to me.

然后更改方法返回类型并为其添加返回:

public static Sword test()throws Exception{
        System.out.println("There is a brass sword and an iron sword. Which do you want?");
        Scanner in = new Scanner(System.in);
        String s = in.next();
        HashMap<String, Sword> options = new HashMap<String, Sword>();
        options.put("brass", new Sword());
        options.put("iron", new Sword());
        Sword k = options.get(s);
        return k;
}