Java 对象数组显示为空

Question

我需要使用对象数组打开一个文本文件，并将其显示到控制台输出。文本文件是一个包含 7 列的 table。我创建了一个对象数组。目前显示：

"F:\stock.txt14行 [[null, null, null, null, null, null, null, null, null, null, null, null, null, null] .....等”应该是每一列的信息。

我已经坚持了一段时间，因为我不确定该怎么做。任何帮助将不胜感激。

public class Stock {

    public Object [][] makeArray() throws IOException {

        int L = 0;
        int currentLine = 0;
        int next = 1;

        File stockFile = new File ("F:\stock.txt");
        Scanner s = null;
        Scanner input = null;
        System.out.print(stockFile);

        try {
            input = new Scanner(new File("F:\stock.txt"));
        }
        catch (FileNotFoundException fileNotFoundException) {
            System.err.println("Error opening stock file.");
            System.exit(1);
        }

        try {
            s = new Scanner (stockFile);        //scan file
            while (s.hasNext()){
                L = L+1;                            //read line
                s.nextLine();                       //read next line
            }
        }
        finally {
            if (s != null){                     //if no more line
                s.close();                      //close
            }
        }

        System.out.println("\n" + L + " lines");

        Object[] partID = new Object[L];
        Object[] manufacturer = new Object[L];
        Object[] partNo = new Object[L];
        Object[] description = new Object[L];
        Object[] stockLevel = new Object[L];
        Object[] lowStock = new Object[L];
        Object[] location = new Object[L];
        Object[][] stockArray = new Object [][] {partID, manufacturer, partNo, description, stockLevel, lowStock, location};

        Scanner fillArray = null;

        return stockArray;
    }
}

Answer 1

在你的 while 循环中需要解析正在读取的行以提取你需要的值并将它们存储在某个地方。

while (s.hasNext()){
    // parse out data and store somewhere
}

当前您正在读取该行，但未对从文件中读取的数据执行任何操作

Java 对象数组显示为空

Java Object array is displaying null

java

arrays

object