java - 为什么我的 hasNextLine() while 循环只工作一次？

Question

我已经为此工作了几个小时，但自己或在线都找不到问题。我不知道为什么第一个循环确实有效，而第二个循环没有继续经过第一次迭代。

File adjacencies = new File(adjacenciesFile);
Scanner adjacenciesScanner = new Scanner(adjacencies);
//idk why this works and the while loop after doesn't 
/*
while(adjacenciesScanner.hasNextLine()){
        System.out.println(adjacenciesScanner.nextLine());
    }
*/

while(adjacenciesScanner.hasNextLine()){
    ArrayList<Country> adjacentCountries = new ArrayList<Country>();
    String[] adjacenciesNames = adjacenciesScanner.nextLine().split(",");

    for(String countryName : adjacenciesNames){
        adjacentCountries.add(this.countries.get(countryName));
    }
    System.out.println(adjacentCountries);
    adjacentCountries.remove(0);
    this.countries.get(adjacenciesNames[0]).addAdjacencies(adjacentCountries);
}

这是我正在读取的文件:

Alaska,Alberta,Northwest Territory,Kamchatka
Alberta,Alaska,Northwest Territory,Ontario,Western United States
Central America,Western United States,Venezuela
Eastern United States,Western United States,Ontario,Quebec
Greenland,Northwest Territory,Ontario,Quebec,Iceland
Northwest Territory,Alaska,Greenland,Ontario,Alberta

没有异常(exception)，只是不会运行多次

Answer 1

如果您设置断点并在 Debug模式下运行它，您应该确切地看到它退出循环的原因。对我来说看起来不错，如果有的话，你可能会在 split() 上遇到异常。