Question

所以我有这段代码：

    package nmishewa.geekycamp.dictionary;

    import java.io.File;
    import java.io.FileNotFoundException;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Scanner;

    public class Main {
        public static File file = new File(                 "C:\\Users\\N\\workspace\\Dictionary\\src\\nmishewa\\geekycamp\\dictionary\\bg_utf8.txt");
        public static int value = 1;
        private static Scanner input;
        public static Scanner in = new Scanner(System.in);
        public static Map<String, Integer> map = new HashMap<String, Integer>();

        public static void main(String[] args) throws FileNotFoundException {
            readFile();
            System.out.println("Enter number of function wanted" + "\n1 to add"
            + "\n 2 for searching by prefix" + "\n for deleting");
            int choice = in.nextInt();
            if (choice == 1) {
                add();
            }
            if (choice == 2) {
                prefixSearch();
            }
            if (choice == 3) {
                remove();
            }
        }

        public static void readFile() throws FileNotFoundException {
            input = new Scanner(file);
            boolean done = false;
            int value = 1;

            while (input.next() != null) {
                String word = input.next().toLowerCase();
                String[] line = word.split("[,\\s]+");
                for (int j = 0; j < line.length; j++) {
                    map.put(line[j], value);
                    value++;
                    done = true;
                }
            }
            if (done == true) {
                System.out.println("Succes");
            }
        }

        public static void prefixSearch() {
            System.out.println("Enter prefix");
            String prefix = in.next().toLowerCase();
            for (Map.Entry<String, Integer> key : map.entrySet()) {
            if (key.getKey().startsWith(prefix)) {
                System.out.println(key.getKey());
            }
        }
    }

    public static void add() {
        System.out.println("Enter words you wish to add");
        boolean done = false;
        while (in.next() != null) {
            String word = in.next().toLowerCase();
            String[] line = word.split("[,\\s]+");
            for (int j = 0; j < line.length; j++) {
                if (!map.containsKey(line[j])) {
                    map.put(line[j], value);
                    value++;
                    done = true;
                } else {
                    continue;
                }
            }
        }
        if (done == true) {
            System.out.println("Succes");
        }
    }

    public static void remove() {
        System.out.println("Enter words you want to remove");
        boolean done = false;
        while (in.next() != null) {
            String word = in.next().toLowerCase();
            String[] line = word.split("[,\\s]+");
            for (int j = 0; j < line.length; j++) {
                if (map.containsKey(line[j])) {
                    map.remove(line[j], map.get(line[j]));
                    value--;
                    done = true;
                } else {
                    continue;
                }
            }
        }
        if (done == true) {
            System.out.println("Succes");
        }
    }
}`

然后抛出

      ` Exception in thread "main" java.util.NoSuchElementException
       at java.util.Scanner.throwFor(Unknown Source)
       at java.util.Scanner.next(Unknown Source)
       at nmishewa.geekycamp.dictionary.Main.readFile(Main.java:41)
       at nmishewa.geekycamp.dictionary.Main.main(Main.java:18)`

带有单词的文件看起来像这样 а аба абаджийски абаджийство абаджия абажур 任何人都知道为什么会这样，以及如何解决它？

Answer 1

用下面的删除方法替换你的while循环条件。

使用while (input.hasNext())代替while(input.next() != null)

Answer 2

在接下来打电话时，你应该检查扫描仪是否有一个。

if(input.hasNext())
 input.next();

参考Scanner

Java从文件中读取抛出noSuchFileException

2 个答案: