java - 想要创建 if 语句，然后是几个 else-if 语句，最后是一个 "capture-all"else-语句

Question

创建一个“海盗对话”，可以选择左手或右手。我希望它对“左”和“右”的不同拼写做出积极的回答(正如您将在代码中看到的那样)，但是，当我为所有非“右”或“左”的输入添加最终的“else”代码时，它给了我一个“java.lang.Error”，无法访问的代码。在添加最终的“else”语句之前，我测试了我的代码，它的工作原理就像我想要的那样，再次添加“else”语句，它给了我同样的错误。

(我也希望获得有关如何改进代码的提示和反馈，这是我完全自己创建的第二个项目)

无论如何，这是代码:

package myOwn;

import java.util.Scanner;

public class myArms {

static Scanner sc2 = new Scanner(System.in);

public static void main(String[] args) {
    armInput();
}

public static void armInput() {
    System.out.println("Behold the arms! Which hand holds the secret item?");
    String answer = sc2.nextLine();
    System.out.println(armOpener(answer));
}

public static String armOpener(String answer) {
    if(answer.equals("left")) {
        return "Aha! Indeed the gemstone was hidden in the left hand. Now...";
    }else if(answer.equals("Left")) {
        return "Aha! Indeed the gemstone was hidden in the left hand. Now...";
    }else if(answer.equals("LEFT")) {
        return "Aha! Indeed the gemstone was hidden in the left hand. Now...";
    }else if(answer.equals("right")) {
        return "Bummer! The treasure was in the other hand. Easy for me to say, huh? What if there wasn't a treasure from the start of? Who knows...";
    }else if(answer.equals("Right")) {
        return "Bummer! The treasure was in the other hand. Easy for me to say, huh? What if there wasn't a treasure from the start of? Who knows...";
    }else if(answer.equals("RIGHT")) {
        return "Bummer! The treasure was in the other hand. Easy for me to say, huh? What if there wasn't a treasure from the start of? Who knows...";
    }else {
        return "Did you not hear me boy? I'm asking you, which hand?!";
    }
    return answer;
}

}

“返回答案；”行是以红色下划线结尾的。如果删除最后一个“else”语句，红色下划线就会消失。

Answer 1

这是因为在所有 if 语句之后，您有一个 return 语句，如果没有任何 if 语句，该语句将永远不会被执行语句匹配，它将转到 else 语句并在那里终止。

如果不满足任何条件，您可以删除 return 行或最后的 else，具体取决于预期的返回值。

...
public static String armOpener(String answer) {
    String ans = answer.toLowerCase();

    if (ans.equals("left")) {
        return "Aha! Indeed the gemstone was hidden in the left hand. Now...";
    } else if (ans.equals("right")) {
        return "Bummer! The treasure was in the other hand. Easy for me to say, huh? What if there wasn't a treasure from the start of? Who knows...";
    }

    return "Did you not hear me boy? I'm asking you, which hand?!";
}
...

此外，您似乎为单词的不同字母大小写(right 和 RIGHT)返回相同的值，可以通过比较变量的小写值。然后，当您有多个这样的 if 时，您可以使用 switch 语句来简化:

...
public static String armOpener(String answer) {
    switch(answer.toLowerCase()) {
        case "left":
            return "Aha! Indeed the gemstone was hidden in the left hand. Now...";

        case "right":
            return "Bummer! The treasure was in the other hand. Easy for me to say, huh? What if there wasn't a treasure from the start of? Who knows...";

        default:
            return "Did you not hear me boy? I'm asking you, which hand?!";
    }
}
...