Question

我试图编写一个从用户那里获取文件名的程序（例如：英文），然后打开这个文件并打印（9个问题）分为（3个级别，每个级别有3个问题），然后打开包含答案的另一个文件（EnglishC），然后将其与正确答案进行比较。如果正确grade++。

输出：

enter your choice:
1.English
2.Math
3.Science

java.io.FileNotFoundException: English.txt (No such file or directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:120)
at java.util.Scanner.<init>(Scanner.java:636)
at Generater.createQuestions(Generater.java:50)
at Generater.choose_subject_And_Level(Generater.java:41)
at Generater.main(Generater.java:139)

来源：

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class Generater {
static int levelNo = 1;
static int subjectName;
static int grade;
static String fileName;
static String fileNameCorrect;
static String ans;
static String correctAns;

public static void choose_subject_And_Level() {
    // here the main will call this method to ask the user what subject to be tested in?
    Scanner input = new Scanner(System.in);

    System.out.println("enter your choice:\n 1.English\n2.Math\n3.Science ");
    subjectName = input.nextInt();

    switch (subjectName) {
    case 1:
        fileName = "English.txt";
        fileNameCorrect = "EnglishC.txt";
        break;
    case 2:
        fileName = "Math.txt";
        fileNameCorrect = "MathC.txt";
        break;
    case 3:
        fileName = "Science.txt";
        fileNameCorrect = "SienceC.txt";
        break;
    }

    createQuestions(fileName, fileNameCorrect, levelNo);

}

public static void createQuestions(String fileName, String fileNameCorrect,
        int levelNo) {

    Scanner input, input2;
    try {
        input = new Scanner(new File(fileName));
        input2 = new Scanner(new File(fileNameCorrect));
        input.useDelimiter("*");

        FileInputStream fs = new FileInputStream(fileName);
        FileInputStream fs2 = new FileInputStream(fileNameCorrect);

        BufferedReader br = new BufferedReader(new InputStreamReader(fs));
        BufferedReader br2 = new BufferedReader(new InputStreamReader(fs2));!

        while (input.hasNext()) {
            switch (levelNo) {
            case 1:
                for (int i = 1,k=1; i <= 3 ; i++,k++) {
                    System.out.printf("\nQ#\f: " + input.next() + "\n" , k);

                    ans = input.next();

                    correctAns = input2.next();

                    if (ans == correctAns) {
                        grade++;
                    }
                }
                break;

            case 2:
                for (int i = 4, k = 1; i <= 6; i++, k++) {

                    try {
                        for (int j = 1; j <= 3; j++) {
                            br.readLine();
                            correctAns = br2.readLine();
                        }
                    } catch (IOException e) {

                        e.printStackTrace();
                    }
                    System.out.printf("\nQ#\f: " + input.next() + "\n" , k);

                    ans = input.next();                 

                    if (ans == correctAns) {
                        grade++;
                    }
                }
                break;

            case 3:
                for (int i = 7, k = 1; i <= 9; i++, k++) {

                    try {
                        for (int j = 1; j <= 6 ; j++){
                            br.readLine();
                            correctAns = br2.readLine();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                    System.out.printf("\nQ#\f: " + input.next() + "\n" , k);

                    ans = input.next();

                    correctAns = input2.next();

                    if (ans == correctAns) {
                        grade++;
                    }
                }
                break;
            }

        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();

    }

}

// the main
public static void main(String[] args) {

    choose_subject_And_Level();

}
}

Answer 1

当抛出java.io.FileNotFoundException时，它意味着应该读取/写入的文件不存在于指定的位置。查看文件系统上文件的位置，并确认存在相关文件（English.txt）。

此处有更多信息：https://docs.oracle.com/javase/7/docs/api/java/io/FileNotFoundException.html

逐行读取文件并打印

1 个答案: