如何从文本文件中读取多个对象然后发送到 ArrayList？

Question

我目前让我的程序使用 BufferedReader 读取第一个对象，但我不确定如何读取多个对象。这是我从文件中读取的代码：

    public Stock getData(){

    StringTokenizer row;
    Stock aStock = new Stock();

    try{
        BufferedReader inbuffer = new BufferedReader(new FileReader(fileName));
        String inputString;
        inputString = inbuffer.readLine();
        if(inputString != null){
            row = new StringTokenizer(inputString, DELIMTER);
            if(row.countTokens() == 4){
                aStock.setStockName(row.nextToken());
                aStock.setStockQuantity(Integer.parseInt(row.nextToken()));
                aStock.setPurchasePrice(Double.parseDouble(row.nextToken()));
                aStock.setCurrentPrice(Double.parseDouble(row.nextToken()));

            }
        }
        inbuffer.close();
    }
    catch(IOException ioe){
        JOptionPane.showMessageDialog(null, ioe.getMessage(), "File Read Error", JOptionPane.ERROR);
    }
    return aStock;
}

我正在读取的文件如下所示：

然后调用我的 bufferedReader 的代码部分如下所示：

    public void loadFile(){
    StockIO stockRead = new StockIO();
    jFileChooser1.showOpenDialog(jPanel3);
    File file = jFileChooser1.getSelectedFile();
    stockRead.loadFileName(file.getName());
    stockArr.add(stockRead.getData());

    int index = 0;
    if(stockArr.get(index) != null){
        DLM.addElement(stockArr.get(0).getStockName());
        index ++;
    }


    listStock.setModel(DLM);

}

所以我试图在我的 bufferedReader 将读取和发送两行代码 through.Currently 的地方获取它，如果我运行这将通过 "Shawn" 行发送所有对象信息，但我也想要 "test" 行。感谢您花时间查看此内容。

Answer 1

您的代码当前在读取第一行后停止，因为没有循环可以继续遍历整个文件。

您可以使用 while 循环来检查在遍历您的行时是否有要读取的行：

while ((line = inbuffer.readLine()) != null) {
   // Process each line
}

import java.util.ArrayList;

public ArrayList<Stock> getData(){

    StringTokenizer row;

    ArrayList<Stock> stockList = new ArrayList<>();

    try{
        BufferedReader inbuffer = new BufferedReader(new FileReader(fileName));
        String inputString;
        Stock aStock;
        // inputString = inbuffer.readLine();
        while ((line = inbuffer.readLine()) != null){
            row = new StringTokenizer(line, DELIMTER);
            if(row.countTokens() == 4){
                aStock = new Stock();
                aStock.setStockName(row.nextToken());
                aStock.setStockQuantity(Integer.parseInt(row.nextToken()));
                aStock.setPurchasePrice(Double.parseDouble(row.nextToken()));
                aStock.setCurrentPrice(Double.parseDouble(row.nextToken()));
                stockList.add(aStock);
            }
        }
        inbuffer.close();
    }
    catch(IOException ioe){
        JOptionPane.showMessageDialog(null, ioe.getMessage(), "File Read Error", JOptionPane.ERROR);
    }

    return stockList;
}

看起来您还需要在 loadFile() 方法中添加一个循环来遍历所有股票。

public void loadFile(){
    StockIO stockRead = new StockIO();
    jFileChooser1.showOpenDialog(jPanel3);
    File file = jFileChooser1.getSelectedFile();
    stockRead.loadFileName(file.getName());

    // Add all new stocks from getData to stockArr
    stockArr.addAll(stockRead.getData());

    // int index = 0;
    for (int index = 0; index < stockArr.length; index++) {
        if(stockArr.get(index) != null){
            DLM.addElement(stockArr.get(index).getStockName());
        }
    }

    listStock.setModel(DLM);

}

如何从文本文件中读取多个对象然后发送到 ArrayList？

How to read multiple objects from a text file and then send to an ArrayList?

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