Question

它显示空异常。现在该怎么办？

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

public class Quiz1 {

    public static void main(String[] args) {
        File f = new File("QuizMark.txt");
        try{
            Scanner s = new Scanner (f);
            QuizMark[] p = new QuizMark[10];
            while(s.hasNext()==true)

            {
                int c = s.nextInt();
                double d = s.nextInt();             
                for(int i=0;i<10;i++){
                p[i]= new QuizMark(c,d);
                System.out.println(p[i].getId());
                System.out.println(p[i].getScore());
                i++;
                }
            }
        }
                catch(Exception e){
                    System.out.println(e.getMessage()); 
                    }
    }

}

Answer 1

首先，你的文件必须定义一个保存在其中的数据模式，如标记和id用逗号或连字符下划线等分隔，无论你喜欢保存模式。每个下一个数据应该在下一行。然后阅读正确的文本保存在文件中的方式。

示例QuizMarks.txt

01,96.5
02,78.9
03,65
04,89.7

Java代码

 int count = 0;
 String s[];
 String line="";
 QuizMark[] p = new QuizMark[10];

 BufferedReader br= new BufferedReader(new FileReader("QuizMark.txt"));

 while(line=br.readLine()!=null){

 s=line.split(",");//your data separated by symbol in file 

 //First Record with id and marks 

 int id =Interger.parseInt(s[0]); //conversion from string to int
 double marks = Double.parseDouble(s[1]); //conversion from string to double

 p[count]= new QuizMark(id,marks);
 count++;


 }

控制台中的输出为null

1 个答案: