尝试初始化2d数组时出现NullPointerException

Question

我收到一个nullPointerException，试图将文本文件中的值添加到二维数组中。前2个值确定行和列。是什么想法扔掉它。忽略异常处理和print语句。我试图让数组初始化，然后回去加强一点。

public Help(String filename) throws FileNotFoundException,
        InvalidFileFormatException {
    this.filename = filename;

    System.out.println("Reading in file: " + filename);

    String number = "";
    int row = 0;
    int col = 0;
    int count = 0;

    try {
        Scanner inputFile = new Scanner(new File(filename));

        while (inputFile.hasNextInt()) {
            row = Integer.parseInt(inputFile.next());
            col = Integer.parseInt(inputFile.next());
            System.out.println("Row : " + row);
            System.out.println("Col : " + col);
            baseMap = new double[row][col];
            System.out.println(baseMap[2][4]);
            for (int i = 0; i < baseMap.length; i++){
                for (int j = 0; j < baseMap[i].length; j++){
                    baseMap[i][j] = Double.parseDouble(inputFile.next());
                }
            }
        }
System.out.println(baseMap[2][4]);
    } catch (Exception e) {
        System.out.println(e.toString());
    } 

输出的 读入文件：sampleMap2.txt 行：5 上校：5 0.0 线程“main”中的异常java.lang.NullPointerException

Answer 1

您希望在这里看到什么价值;

baseMap = new double[row][col];
System.out.println(baseMap[2][4]);

如果row == 1怎么样？

如果没有更多数据，那该怎么办：

baseMap[i][j] = Double.parseDouble(inputFile.next());

也许你的数据不够。