如何從Java中的文本文件讀取特定行？

Question

我正在使用文件中的信息創建測驗游戲。 文本文件將包含所有問題，答案和正確答案。 文本文件的結構如下：

Question
answer 1
answer 2
answer 3
answer 4
The right answer repeated

使用從文件中讀取的信息，我正在創建多個測驗。 我將所有問題保存在一個數組中，將答案保存在另一個數組中，並將正確答案（重復）保存在另一個數組中。 有什么辦法可以使用掃描儀轉到文件中的特定行？

到目前為止，這就是我所擁有的。 我能夠從文件中獲取所有問題，但是我不知道如何讀取答案（我在這里省略了用於獲取文件名和計數行數的方法的代碼，因為我知道這些工作）：

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

//for the file, it is assumed that it is structured as follows: question /n, answer 1 /n, answer 2 /n, 
//answer 3 /n, answer 4 /n, correct answer repeated

public class CoreCode {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    String fileName = getFile();
    // gets the file and deals with exceptions
    Scanner fileIn = null;
    try {
        fileIn = new Scanner(new File(fileName));
    } catch (FileNotFoundException e) {
        System.out.println("Error. File not found.");
        // e.printStackTrace();
    }

    //counts number of lines in the program
    int numberOfLines = countLines(fileIn);

    //Every sixth line is a question
    int numberOfQuestions = numberOfLines / 6;
    fileIn.close();

    fileIn = null;
    try {
        fileIn = new Scanner(new File(fileName));
    } catch (FileNotFoundException e) {
        System.out.println("Error. File not found.");
    }

    //create an array of the questions from the file
    String[] questions = getQuestions(fileIn, numberOfQuestions);
    fileIn.close();
    for (int i = 0; i < questions.length; i++){
        System.out.println(questions[i]);
    }

}

// method to get file name
public static String getFile() {

}

//method to count total lines in file
public static int countLines(Scanner fileIn) {

}

// method to read questions
public static String[] getQuestions(Scanner fileIn, int numberOfQuestions) {
    String[] questions = new String[numberOfQuestions];
    int count = 0;

    //method 2, every sixth line is a question
    while (fileIn.hasNext()){
        String line = fileIn.nextLine();
        if (count == 0 || count % 6 == 0){
            //count is number of total lines, so the index is count  divided by 6 (every sixth lines is 
            //a question
            int index = count / 6;
            questions[index] = line;
        }
        count++;
    }

    return questions;
}

}

Answer 1

 LineIterator it = IOUtils.lineIterator(
       new BufferedReader(new FileReader("file.txt")));
 for (int lineNumber = 0; it.hasNext(); lineNumber++) {
    String line = (String) it.next();
    if (lineNumber == expectedLineNumber) {
        return line;
    }
 }

由於有緩沖區，這將稍微更有效。

看看Scanner.skip(..)

Answer 2

我將按照另一個答案的建議，使用BufferedReader讀取文件，並將信息保存在包含以下內容的對象中：

class Question {
    String question;
    String[] answers;
    String correctAnswer;
}

然后，在讀取文件之后，您將在內存中存儲所有問題和答案（存儲在ArrayList ）。 這樣，您將只讀取一次文件。