java - 没有这样的元素异常(exception)吗？

Question

这是我的代码:

public static void getArmor(String treasure)
    throws FileNotFoundException{
    Random rand=new Random();
    Scanner file=new Scanner(new File ("armor.txt"));
    while(!file.next().equals(treasure)){
        file.next(); //stack trace error here
        }
    int min=file.nextInt();
    int max=file.nextInt();
    int defense=min + (int)(Math.random() * ((max - min) + 1));
    treasure=treasure.replace("_", " ");
    System.out.println(treasure);
    System.out.println("Defense: "+defense);
    System.out.println("=====");
    System.out.println();
    }

public static void getTreasureClass(Monster monGet)
throws FileNotFoundException{
    Random rand = new Random();
    String tc=monGet.getTreasureClass();
    while (tc.startsWith("tc:")){
        Scanner scan=new Scanner(new File ("TreasureClassEx.txt"));
        String eachLine=scan.nextLine();
        while(!tc.equals(scan.next())){
        eachLine=scan.nextLine();
        }
        for (int i=0;i<=rand.nextInt(3);i++){
            tc=scan.next();
        }
    getArmor(tc); //stack trace error here
    }
 }

由于某种原因，我收到“无此类元素异常”

    at java.util.Scanner.throwFor(Scanner.java:907)
at java.util.Scanner.next(Scanner.java:1416)
at LootGenerator.getArmor(LootGenerator.java:43)
at LootGenerator.getTreasureClass(LootGenerator.java:68)
at LootGenerator.getMonster(LootGenerator.java:127)
at LootGenerator.theGame(LootGenerator.java:19)
at LootGenerator.main(LootGenerator.java:11)

但我不知道为什么。基本上我的程序正在搜索两个文本文件 -armor.txt 和 TreasureClassEx.txt。 getTreasureClass 从怪物处接收宝藏类别，并搜索 txt，直到到达基础盔甲元素(不以 tc: 开头的字符串)。然后，它在 getArmor 中搜索与其所获得的基础盔甲名称相匹配的盔甲宝藏类。任何意见，将不胜感激!谢谢!

txt 文件的链接位于:http://www.cis.upenn.edu/~cis110/hw/hw06/large_data.zip

Answer 1

看起来您正在调用 next，即使扫描器不再有下一个元素可提供...抛出异常。

while(!file.next().equals(treasure)){
        file.next();
        }

应该是这样的

boolean foundTreasure = false;

while(file.hasNext()){
     if(file.next().equals(treasure)){
          foundTreasure = true;
          break; // found treasure, if you need to use it, assign to variable beforehand
     }
}
    // out here, either we never found treasure at all, or the last element we looked as was treasure... act accordingly