如何使用 Scanner 的分隔符方法

Question

我目前正在开发游戏风险。在构建国家、大洲及其邻接关系的 Board 课程中，我正在阅读三个不同的文本文件。当我构建一个新大陆时，它的构造函数期望以下 （字符串名称、int bonusArmies、ArrayList memberCountries）。 现在，我正在使用扫描仪从这样组织的文本文件中读取， 它拥有的名称、奖金军队，以及每条线上的其余部分是它的成员国。

北美,5,阿拉斯加,阿尔伯塔,中美洲,美国东部,格陵兰,西北地区,安大略,魁北克,美国西部 南美,2,阿根廷,巴西,委内瑞拉 欧洲,5,英国,冰岛,北欧,斯堪的纳维亚,南欧,乌克兰,西欧 非洲,3,刚果,东非,埃及,马达加斯加,北非,南非 亚洲,7,阿富汗,中国,印度,伊尔库茨克,日本,堪察加,中东,蒙古,暹罗,西伯利亚,乌拉尔,雅库茨克 澳大利亚,2,东澳大利亚,印度尼西亚,LotR,新几内亚,西澳大利亚

我知道我需要为 Scanner 设置分隔符，我尝试了多种方法，但无济于事。这是我尝试创建 Continents 哈希图的示例。

public void createContinents()
{   

    Scanner inputTwo = new Scanner( new File( "continents.txt");

while( inputTwo.hasNext())  //continues to create and add countries until their are none next
{   
    String line = inputTwo.nextLine();  //stores the entire line
    Scanner lineScan = new Scanner( line);  //passes the entire line into Scanner
    lineScan.useDelimiter(","); //sets the Scanner's delimiter pattern

    String name = inputTwo.next();  //stores the first String which is the name of the current continent being created
    System.out.println( " the name is" + name);

    int bonusArmies = inputTwo.nextInt();   //stores the second String which is casted into an int for the continent bonus armies
    System.out.println(" the number of bonus armies is" + bonusArmies);

    ArrayList<Country> memberCountries = new ArrayList<Country>();  //creates an arraylist to hold the member countries of current continent

    while( inputTwo.hasNext())  //goes through the rest of the line to add the member countries until it reaches the end of the line
    {   

        memberCountries.add( countries.get(inputTwo.next()));//gets string name of country and pass it as key to store into temp arraylist of countries         
        System.out.println( "the member countries" + memberCountries);
    }

        continent = new Continent( name,  bonusArmies,  memberCountries);   //creates continent
        continents.put(name , continent);   //associates a key to the current continent

}


    inputTwo.close();

 }    

这是该图像中的文本。

    PS C:\Users\repti_000\desktop\risk\homeworks2120\game> java BoardTester
     the name is
    SouthAmerica,2,Argentina,Brazil,Venezuela 

    Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Unknown Source)
    at java.util.Scanner.next(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at java.util.Scanner.nextInt(Unknown Source)
    at Board.createContinents(Board.java:66)
    at Board.loadBoard(Board.java:141)
    at Board.<init>(Board.java:27)
    at BoardTester.main(BoardTester.java:7)
   PS C:\Users\repti_000\desktop\risk\homeworks2120\game>

Answer 1

我重命名了扫描仪和一些变量以使其更清晰，并添加了一些带有 CHANGED 的 cmets。我想知道为什么您的哈希图大陆看起来像大陆（名称，大陆），而您的存储大陆的名称（正如您在构造函数中给出的那样）。使用continent.getName() 似乎是一种更好的做法。

正如 RotN 爵士所指出的，您使用了错误的扫描仪，而且您的姓名确实不清楚。尽量让你的变量名更清楚一点，这应该有助于节省时间。

    public void createContinents()  { 

    //  Scan the continents.txt file
    Scanner worldScan = new Scanner( new File( "continents.txt");

    //  While worldScan has a next line, run loop
    //  CHANGED: not hasNext(), but hasNextLine()
    while( worldScan.hasNextLine()) {

        //  Create a scanner for the selected line in worldScan
        String continentLine = inputTwo.nextLine();
        Scanner continentScan = new Scanner(continentLine);
        continentScan.useDelimiter(",");

        //  Grab the continent from the scanner
        String name = continentScan.next();
        System.out.println( " the continent name is" + name);

        //  Grab the armies from the scanner
        //  CHANGED: you read it out as a string, not as an int
        int bonusArmies = Integer.toString(continentScan.next());
        System.out.println(" the number of bonus armies is" + bonusArmies);

        //  Instantiate loop variable countries
        ArrayList<Country> memberCountries = new ArrayList<Country>();

        while( continentScan.hasNext()) {
            memberCountries.add(countries.get(continentScan.next()));
            System.out.println( "the member countries" + memberCountries);
        }

        //  Instantiate loop variable continent
        Continent continent = new Continent( name,  bonusArmies,  memberCountries);

        //  Add continent to the hashmap
        continents.put(name,continent);

        continentScan.close();
    }

    worldScan.close();
 }

Answer 2

您从 inputTwo 而不是 lineScan 获取数据。您应该在这里考虑更清晰的名称，这样可以更轻松地检测到此类问题。而不是 inputTwo mapData 或 worldScanner 而不是 lineScan 可能是continentData。