java - 将字符串数组转换为 double 组

Question

我正在尝试将 txt 文件中的数字列表转换为数字数组。有 26 个数字，每个数字位于文本文件中的不同行上。我的代码是

import java.io.*;
public class rocket {

    public static void main(String[] args) throws IOException, FileNotFoundException
    {
        BufferedReader b = new BufferedReader(new InputStreamReader(new FileInputStream("/Users/Jeremy/Documents/workspace/altitude.txt")));
        String[] stringArray = new String[25];
        double[] doubleArray = new double[stringArray.length];
        for(int i=0; i<25; i++)
        {
            stringArray[i] = b.readLine();
            doubleArray[i] = Double.parseDouble(stringArray[i]);
        }
        for(int i = 0; i<doubleArray.length; i++)
        {
            System.out.println(doubleArray[i]);
        }
    }
}

但是每次运行它时我都会遇到数字格式异常。如果我尝试打印出字符串，我会得到一个 indexOutOfBounds 异常

Answer 1

有问题时，您提到有 26 个字符串，因此需要声明

String[] stringArray = new String[26];

当 readline 返回并带有 linbreak 时，会发生数字格式异常。要读取行，您可以执行以下操作

 public String[] readLines(String filename) throws IOException {
        FileReader fileReader = new FileReader(filename);
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        List<String> lines = new ArrayList<String>();
        String line = null;
        while ((line = bufferedReader.readLine()) != null) {
            lines.add(line);
        }
        bufferedReader.close();
        return lines.toArray(new String[lines.size()]);
    }

所以按照这个逻辑，你可以获得双倍

public static Double[] readLines(String filename) throws IOException {
    FileReader fileReader = new FileReader(filename);
    BufferedReader bufferedReader = new BufferedReader(fileReader);
    List<Double> lines = new ArrayList<Double>();
    String line = null;
    while ((line = bufferedReader.readLine()) != null) {
        lines.add(Double.parseDouble(line));
    }
    bufferedReader.close();
    return lines.toArray(new Double[lines.size()]);
}