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java - 如何使用Scanner的分隔符方法

转载 作者:行者123 更新时间:2023-11-30 03:56:32 25 4
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我目前正在致力于游戏《Risk》的实现。在构建国家、大陆及其邻接关系的 Board 类中,我正在阅读三个不同的文本文件。当我 build 一个新大陆时,它的 builder 期望以下内容(字符串名称,int BonusArmies,ArrayList memberCountries)。现在,我正在使用扫描仪读取组织如下的文本文件,其名称、所拥有的奖励军队,每一行的其余部分是其成员国。

北美洲,5,阿拉斯加州,艾伯塔省,中美洲,美国东部,格陵兰岛,西北地区,安大略省,魁北克省,美国西部南美洲,2,阿根廷,巴西,委内瑞拉欧洲,5,英国,冰岛,北欧,斯堪的纳维亚半岛,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,堪察加半岛,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

我知道我需要为扫描仪设置一个分隔符,我尝试了多种方法,但没有成功。这是我尝试创建大陆 HashMap 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();

}

Here is a picture of the error I get when test running it

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>

最佳答案

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 的注释。我想知道为什么你的 HashMap 大陆看起来像大陆(名称,大陆),而你存储大陆的名称(正如你用构造函数给出的那样)。使用 Continental.getName() 似乎是更好的做法。

正如 RotN 爵士所指出的,您使用了错误的扫描仪,而且您的名字确实不清楚。尽量让你的变量名称更清晰一些,这应该有助于时间。

    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();
}

关于java - 如何使用Scanner的分隔符方法,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23033893/

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