Question

我在WeatherAnalysis.main（WeatherAnalysis.java：37）得到一个“线程中的异常”主“java.lang.ArrayIndexOutOfBoundsException：5”“我不确定第37行有什么问题，date [CurrentLine] [0 ] =（int）fullDate％100;。尝试使用.txt文件输出1941年至2013年的天气模式。

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class WeatherAnalysis {

    public static void main(String[] args)  throws FileNotFoundException {

        int NumberOfDays = 0;
        String station;
        File f = new File("PortlandWeatherCut.txt"); //Import text file.
        Scanner input= new Scanner(f);
        input.nextLine();
        input.nextLine();

        while (input.hasNextLine()) {  //Assign number of days to be         
            NumberOfDays++;
            input.nextLine();
        }

        double[][] date = new double[NumberOfDays][3];
        double[] prcp = new double[NumberOfDays];
        double[] snow = new double[NumberOfDays];
        double[] snwd = new double[NumberOfDays];
        double[] tmax = new double[NumberOfDays];
        double[] tmin = new double[NumberOfDays];
        int CurrentLine = 0;
        double fullDate = 0.0;

        File g = new File("PortlandWeather.txt"); //Import text file.
        Scanner weather= new Scanner(g);
        weather.nextLine(); weather.nextLine();

        while(weather.hasNextLine()) { //variables and converts to inches.
        station = weather.next();
        fullDate = weather.nextDouble();
        date[CurrentLine][0] = (int)fullDate % 100;
        date[CurrentLine][1] = ((int)fullDate % 10000) / 100;
        date[CurrentLine][2] = (int)fullDate / 10000;
        prcp[CurrentLine] = weather.nextDouble()* .00393701;
        snow[CurrentLine] = weather.nextDouble()* 0.0393701;
        snwd[CurrentLine] = weather.nextDouble()* 0.0393701;
        tmax[CurrentLine] = (weather.nextDouble() / 10.0) * (9.0/5.0) + 32.0;
        tmin[CurrentLine] = (weather.nextDouble() / 10.0) * (9.0/5.0) + 32.0;
        CurrentLine++;
        weather.nextLine();
    }
    int indexPoint = 0;
    int nextPoint = 1;
    int endPoint = 0;
    for (int x = 1; x < date.length; x++){ 
        //loop that calculates array section to be averaged,
        //uses a method to average them, then prints a table
        do {
                nextPoint++;
                endPoint++;
        }
        while(((int)date[nextPoint - 1][02] / 10) == ((int)date[nextPoint][1] / 10)); 
        if ( nextPoint < date.length) {
        System.out.printf("%4.0f's Average Max Temp = %4.1f\tAverage Min   Temp = %4.1f\n",
                 date[indexPoint][02],arrayAvg(tmax, indexPoint, endPoint),
                    arrayAvg(tmin, indexPoint, endPoint));
            indexPoint = nextPoint;
            } else 
                System.out.println();

        }
    }
    public static double arrayAvg(double a[], int fromIndex, int toIndex) {
        //Averages the values between the entered parameters and returns it.
        double sum = 0;
        double divisor = 0;
        for (int i = fromIndex; i < toIndex; i++){
            if (a[i] == 393.6616299) {
                divisor++;
            } else {
                sum += a[i];
                divisor++;
            }   
        }
        double average = sum / divisor;
        return average;
    }
}

Answer 1

好像你的问题在第37行。我认为那是

date[currentline][0] = (int)fullDate%100

在你的while循环中。循环继续在创建日期二维数组的NumberOFdAYS之上，因此它抛出了回合。

我的第一个建议是将这个怪物功能分解为更小的功能（查找单一责任原则）。

我的第二个建议是做TDD（测试驱动开发）

但是如果你想要一个快速而又脏的调试，请在while循环开始时执行以下操作：

System.out.printf("Current line = %d, does weather has next line? = %b", CurrentLine, weather.hasNextLine)

这将显示异常之前currentLine的所有值，并显示布尔值。

线程“主”第37行中的异常

1 个答案: