无法读取 .csv 文件。从 JOptionPane 切换到控制台 I/O 后出现 FileNotFoundException 错误

Question

这是同一方法的两个版本。第一个使用 JOptionPane，第二个使用控制台。他们应该从用户输入中获取文件路径（字符串）来查找文件并读取它。

第一种方法工作得很好，但是使用控制台的第二种方法给了我一个 FileNotFoundException 错误。如果它们几乎相同，为什么第二个不起作用？

//使用 JOptionPane ///////////////////////////////////////// /////////////

public void addFromFile() {

    String[] option1 = { "Go back to Main Manu", "Continue" };

    int choice4 = JOptionPane.showOptionDialog(null,
            "Warning: this method will delete existing data before it add file data", "Monster Database",
            JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null, option1, null);

    if (choice4 == 0)
        monitor();

    if (choice4 == 1) {

        monsterAttackList.clear();

        Scanner input = new Scanner(System.in);
        String filePath = JOptionPane.showInputDialog(null, "Enter a filepath");

        File inFile = new File(filePath);

        try {
            Scanner fileReader = new Scanner(inFile);

            String line;
            String[] part;
            int attackID;
            String monster;
            String date;
            String location;
            String reporter;

            while (fileReader.hasNextLine()) {
                line = fileReader.nextLine();
                part = line.split(",");
                attackID = Integer.parseInt(part[0]);
                monster = part[1];
                date = part[2];
                location = part[3];
                reporter = part[4];

                monsterAttackList.add(new MonsterAttack(attackID, monster, date, location, reporter));
            }

            fileReader.close(); // Close to unlock.
            input.close();

        } catch (IOException e) {
            JOptionPane.showMessageDialog(null, "filepath is not valid");
            System.err.println(e);

        }
    }

}   

// 使用扫描仪 ///////////////////////////////////////// //////////////////////

public void addFromFile() {

    System.out.println("Warning: this method will delete existing data before it add file data");
    System.out.println("\n1. Go back to Main Manu" + "\n2. Continue \n");

    Scanner input = new Scanner(System.in);
    int choice4 = input.nextInt();


    if (choice4 == 1)
        monitor();

    if (choice4 == 2) {

        monsterAttackList.clear();

        System.out.println("Enter a filepath");

        String filePath = input.nextLine();

        File inFile = new File(filePath);

        try {
            Scanner fileReader = new Scanner(inFile);

            String line;
            String[] part;
            int attackID;
            String monster;
            String date;
            String location;
            String reporter;

            while (fileReader.hasNextLine()) {
                line = fileReader.nextLine();
                part = line.split(",");
                attackID = Integer.parseInt(part[0]);
                monster = part[1];
                date = part[2];
                location = part[3];
                reporter = part[4];

                monsterAttackList.add(new MonsterAttack(attackID, monster, date, location, reporter));
            }

            fileReader.close(); // Close to unlock.
            input.close();

        } catch (IOException e) {

            System.out.println("filepath is not valid");
            System.err.println(e);

        }
    }

}

Answer 1

您需要在每次致电 input.nextInt() 后致电 input.nextLine()。 NextInt 不消耗换行符，只消耗数字。