Question

我需要阅读的文件如下所示：

30 15
6 3
12 20
3 4

（没有要点）

inputStream不读取30和15，但它读取所有其他的。

如何让inputStream读取第一行？

import java.io.*;
import java.util.*;

public class Program6 {
    //  private static Fraction [] fractionArray;
    public static void main(String[] args) throws FileNotFoundException, IOException {
        System.out.println("Please enter the name of the input file: ");


        Scanner inputFile = new Scanner(System.in);
        Scanner outputFile = new Scanner(System.in);

        String inputFileName = inputFile.nextLine();
        System.out.println("Please enter the name of the output file: ");
        String outputFileName = outputFile.nextLine();
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));
        FileWriter fileWriter = new FileWriter(outputFileName, true);
        //Declaring an inputstream to get file
        Scanner inputStream = new Scanner(new FileInputStream(inputFileName));


        //while the file still has a line
        while (inputStream.hasNextLine()) {
            String theLine = inputStream.nextLine();
            if (theLine.length() >= 0) {
                //declares a numerator and denominator from the file
                int num = inputStream.nextInt();
                int denom = inputStream.nextInt();
                //new fraction from file
                Fraction fract = new Fraction(num, denom);
                fract.reduce();
                System.out.println(fract);
                fileWriter.write("" + fract + "\r\n");
            }
        }

        //closes streams and flushes the file writer
        fileWriter.flush();
        fileWriter.close();
        inputStream.close();
    }
}

Answer 1

这里的问题是Scanner.nextLine()消耗InputStream的输入行。然后，使用Scanner.nextInt()返回使用相同的InputStream - 它不会消耗nextLine()返回的值。

所以，请使用其中一个。

如果使用nextLine()方法，则需要解析包含该行的String以提取值。使用scanner.nextInt()，文件中的整数值立即可用。唯一的损失是你不知道价值是在同一条线上还是在不同的线上。

FileInputStream没有读取第一个值

1 个答案: