java - 将整数写入文件错误

Question

这是我的代码:

public static void main(String[] args) throws IOException {
        writeToFile ("c:\\scores.txt");
        processFile("c:\\scores.txt");
    }
    public static void writeToFile (String filename) throws IOException {
        BufferedWriter outputWriter = new BufferedWriter(new FileWriter(filename));
        Scanner reader = new Scanner (System.in);
        int Num;
        System.out.println ("Please enter 7 scores");
            for (int i = 0; i < 7; i++) {

                Num= reader.nextInt ();

                outputWriter.write(Num);      

                if(i!=6) {
                    outputWriter.newLine();
                }
            }

        outputWriter.flush(); 
        outputWriter.close();
}

    public static void processFile (String filename) throws IOException, FileNotFoundException 
    {
        double sum=0.00;
        double number;
        double average;
                int count = 0;
        BufferedReader inputReader = new BufferedReader (new InputStreamReader(new FileInputStream(filename)));
        String line;

        while((line = inputReader.readLine()) != null)
        {
            number= Double.parseDouble(line); 
                        System.out.println(number);
                        count ++;
            sum += (number);
            System.out.print ("Total Sum:  ");
            System.out.println(sum);
            System.out.print("Average of Scores:  ");
            average=sum/count;
            System.out.println(average);
        }       
        inputReader.close();
    }

这就是我的输出。

Please enter 7 scores
2
3
5
6
8
9
1
Exception in thread "main" java.lang.NumberFormatException: empty String
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1011)
    at java.lang.Double.parseDouble(Double.java:540)
    at writefile.Writefile.processFile(Writefile.java:52)
    at writefile.Writefile.main(Writefile.java:19)
Java Result: 1

我不知道如何解决这个问题。我不确定如何解决 float 小数或空字符串错误。文件中有奇怪的符号，没有整数。我该如何解决？请具体说明，因为我只是 Java 的初学者。

Answer 1

outputWriter.write(1); 不代表 outputWriter.write("1");您需要将 outputWriter.write(Num); 更改为 outputWriter.write(""+Num);请引用 outputstream.write(int)