Question

我在上周试图弄清楚如何使这个愚蠢的代码工作。除了从我的文本文件中读取外，我已设法让一切工作正常。它可以读取一行上的单个整数，但是当给定一个由空格分隔的多个整数的行时，它会变得怪异。现在我已经离开并尝试修复它，代码甚至不再编译。只有一行导致问题。我不擅长编码，所以我不知道从哪里开始。是的，我在网上看了这个。是的，我查了一下论坛。是的，我尝试了多种不同的方法来完成这项工作.... 我该如何解决？？：（

ArrayList<Integer> list = new ArrayList<Integer>();
// the above line is in a different method in the same class, but it's relevant here


File file = new File("C:\\Users\\Jocelynn\\Desktop\\input.txt");
    BufferedReader reader = null;

    try
    {
        reader = new BufferedReader(new FileReader(file));
        String text = null;


        while ((text = reader.readLine()) != null)
        {
            // I want the following line to read "218 150 500 330", and to store each individual integer into the list. I don't know why it won't work :(
            list.add(Integer.parseInt(src.next().trim()));
        }
    } 
    catch (FileNotFoundException e)
    {
    e.printStackTrace();
    } 
    catch (IOException e) 
    {
    e.printStackTrace();
    } 
    try
    {
   reader.close();
    }
    catch (IOException e) 
    {
    e.printStackTrace();
    }


//print out the list
System.out.println(list);

谢谢你的帮助！我确信我只是错过了一些非常简单的事情......

Answer 1

您可以使用Scanner(String)之类的

while ((text = reader.readLine()) != null) {
    Scanner scanner = new Scanner(text);
    while (scanner.hasNextInt()) {
        list.add(scanner.nextInt());
    }
}

当然，使用try-with-resources Statement和diamond operator以及Scanner(File)之类的

可以简化您的整个方法

public static void main(String[] args) {
    File file = new File("C:\\Users\\Jocelynn\\Desktop\\input.txt");

    List<Integer> list = new ArrayList<>();
    try (Scanner scanner = new Scanner(file);) {
        while (scanner.hasNextInt()) {
            list.add(scanner.nextInt());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    // print out the list
    System.out.println(list);
}

Answer 2

在 while 循环

中进行此操作

String[] individualArray = text.split(" ");//note space
for(String individual:individualArray){
    yourList.add(individual);//You need to parse it to integer here as you have already done
}

在上面的代码中， individualArray 将包含separated by space的每个单独的整数。在 for循环内，每个字符串需要解析为整数，然后添加到列表中

Answer 3

试试这个：

public static void main(String[] args) {

        ArrayList<Integer> list = new ArrayList<Integer>();
        File file = new File("C:\\Users\\Jocelynn\\Desktop\\input.txt");
        BufferedReader reader = null;

        try
        {
            reader = new BufferedReader(new FileReader(file));
            String text = null;

            while ((text = reader.readLine()) != null)
            {
                // you need only this for loop in you code.
                for (String value : text.split(" ")) {  // get list of integer
                     if(!value.equals(""))             // ignore space                      
                     list.add(Integer.parseInt(value));  // add to list
                }

            }
        } catch (FileNotFoundException e)
        {
            e.printStackTrace();
        } catch (IOException e)
        {
            e.printStackTrace();
        }
        try
        {
            reader.close();
        } catch (IOException e)
        {
            e.printStackTrace();
        }

        // print out the list
        System.out.println(list);

    }

从带有空格的文本文件中读取然后放入arrayList

3 个答案: