Java文件-I/O不读取

Question

我在维护java为我读取文件时遇到问题。我有一本书。包含所有丹麦岛屿的txt文件，但不管我如何尝试，它都不会显示在控制台中。

这是带有main方法的类。从这里它读取文件并拆分行以将数据放入ArrayList中。

public class DanishIslandFileReader {

private File inFile;
private List<DanishIsland> islandList;

public DanishIslandFileReader(String fName) {
    inFile = new File(fName);
}

private void readFile() {
    islandList = new ArrayList<DanishIsland>();
    Scanner scan = null;
    try {
        scan = new Scanner(inFile);
    } catch (FileNotFoundException fnfe) {
        System.out.println(fnfe);
    }
    while (scan.hasNext()) {
        String line = scan.nextLine();
        String[] tokens = line.split(" ");

        String name = tokens[0];
        double circ = Double.parseDouble(tokens[1]);
        double area = Double.parseDouble(tokens[2]);
        int addr = Integer.parseInt(tokens[3]);
        int adkm = Integer.parseInt(tokens[4]);

        DanishIsland island = new DanishIsland(name, circ, area, addr, adkm);
        System.out.println(island.toString());
        islandList.add(island);
    }

    scan.close();
}

public List<?> getList() {
    return islandList;
}

/**
 * @param args the command line arguments
 */
public static void main(String[] args) throws FileNotFoundException {
    System.out.println(new File(".").getAbsolutePath());
//        DanishIslandFileReader fr = new DanishIslandFileReader("Islands punktum.txt");
    DanishIslandFileReader fr = new DanishIslandFileReader("Islands komma.txt");
    fr.readFile();

    System.out.println("Result:\n" + fr.getList());

}

}

当行被拆分后，它将通过另一个类，该类将数据转换为字符串，并将其放入另一个Arraylist，该Arraylist将在控制台中打印。

public class DanishIsland {

private String name;
private double circumference;
private double area;
private int addresses;
private int addrPerKm2;

public DanishIsland(String name, double circumference, double area,
        int addresses, int addrPerKm2) {
    super();
    this.name = name;
    this.circumference = circumference;
    this.area = area;
    this.addresses = addresses;
    this.addrPerKm2 = addrPerKm2;
}

public String getName() {
    return name;
}

public double getCircumference() {
    return circumference;
}

public double getArea() {
    return area;
}

public int getAddresses() {
    return addresses;
}

public int getAddrPerKm2() {
    return addrPerKm2;
}

@Override
public String toString() {
    StringBuilder builder = new StringBuilder();
    builder.append(name);
    builder.append("\t");
    builder.append(circumference);
    builder.append("\t");
    builder.append(area);
    builder.append("\t");
    builder.append(addresses);
    builder.append("\t");
    builder.append(addrPerKm2);
    builder.append("\n");
    return builder.toString();
}

}

我不会得到任何错误或异常，程序会一直运行，直到它认为列表已经打印出来。

问题是这个列表是空的，我似乎无法从列表中做出任何形式的“sout”。txt文件。我做错了什么？

Lolland 298,388 1234,96 38919 32
Bornholm 108,047 588,025 27125 46
Falster 145,926 516,268 26654 52
Mors 139,254 361,745 12374 34

Answer 1

你试过调试它吗？我认为它没有进入

while (scan.hasNext())

因为扫描。hasNext返回false。这可能是文件权限问题。

这也可能是相关的：为什么hasNext（）False，但hasNextLine（）是True？