Question

在我的程序中，我使用DoubleStream来对数组的值求和。

我有以下代码培训P列表

import java.io.*; 
import java.util.*;
import java.lang.*;
import java.util.stream.DoubleStream;
public class TrainingPList
{
    int aSize=500; // size of constant
    TrainingP[] arrayTrainingP= new TrainingP[aSize]; // array name + aSize constant called to define size of the array
    int nextPosition=0;// size of constant

    double[] MoneyList;

    public void readPersonal()
    {
        try
        {
            BufferedReader br=new BufferedReader(new FileReader("TrainingP.txt"));
            String theNextPublicInfo = br.readLine();
            nextPosition=0;
        while (theNextPublicInfo !=null)
        {
            String[] arrayStringPersonalInfo = theNextPublicInfo.split(",");
            TrainingP tempPInfo = new TrainingP();
            tempPInfo.AthleteID = arrayStringPersonalInfo[0];
            tempPInfo.rMoneyRaised = Double.parseDouble(arrayStringPersonalInfo[1]);

            arrayTrainingP[nextPosition] = tempPInfo;
            nextPosition++;
            theNextPublicInfo = br.readLine();
        }
        }
        catch(Exception e)
        {
            System.out.println("Invalid read data");
        }
    }

    public void outputarrayTrainingP()
    {
    for(int i=0;i<nextPosition;i++)
        {
            System.out.println ("Position "+":"+arrayTrainingP[i]);
        }
    }

    public void ListAth()
    {
        AthList = new String[nextPosition];

        for(int i=0;i<nextPosition;i++)
        {
            AthList[i]=arrayTrainingP[i].AthleteID+"";
        }
    }

    public void ListMoney()
    {
        MoneyList = new double[nextPosition];

        for(int i=0;i<nextPosition;i++)
        {
            MoneyList[i]=arrayTrainingP[i].rMoneyRaised;
        }

        DoubleStream d = DoubleStream.of(MoneyList);
        double dv = d.sum();
        System.out.println("The sum is " + dv);
    }

    public static void main(String[] args)
    {
        TrainingPList tp = new TrainingPList();
        tp.ListMoney();
        tp.readPersonal();
        tp.outputarrayTrainingP();
    }
}

TrainingP

 public class TrainingP
{
    String AthleteID;
    double rMoneyRaised;

    public String toString()
    {
        return AthleteID+","+rMoneyRaised;
    }
}

文档

DJ44,136.0
DB15,0.0

rMoneyRaised只有两个值，它们分别为136.0和0.0。但是它只返回0.0而不是值136.0。有谁知道问题是什么？

Answer 1

主要方法存在问题：

public static void main(String[] args)
{
    TrainingPList tp = new TrainingPList();
    tp.ListMoney();
    tp.readPersonal();
    tp.outputarrayTrainingP();
}

您应该在阅读数据后调用tp.ListMoney()，而不是之前。

DoubleStream返回值0.0时应为136.0

1 个答案: