在Java中将逗号分隔的文件读入多维数组

Question

我想把一个多项选择题列表读成一个多维数组在Java，文件的格式是：问题，answer1，answer2，answer3，answer4，CorretAnswer。

一公里有几米？，1，10，100，1000，4，彩虹童谣里哪种颜色不是？，蓝色，粉色，黑色，橙色，3一个足球队在场上有几个队员？，10，11，12，13，2

所以我希望数组的格式为question[][]，如果n是1，那么question[n][1]将是CSV文件中的第一个问题，然后选择一个问题，我可以将n更改为任何我想要的。

我不知道会有多少问题，他们将不断添加或删除从CSV文件，所以不会有一个静态的数量。所以问题是如何以简单的方式从CSV文件加载所有的问题？

Answer 1

当您到了必须为数据层次结构创建二维数组的地步时，您可能应该为其创建一个明智的模型。

这里有一个快速（和脏）的模型为您（setters丢弃为键入速度）：

问卷类别：

/**
 * Facilitates an entire questionnaire
 */
public class Questionnaire extends ArrayList<Question> {

    /**
     * This questionnaire's name
     */
    private String name;

    /**
     * Creates a new questionnaire using the specified name
     * @param name  The name of this questionnaire
     */
    public Questionnaire(String name) {
        this.name = name;
    }

    /**
     * Returns the name of this questionnaire
     */
    public String getName() {
        return name;
    }
}

问题类：

/**
 * Facilitates a question and its answers
 */
public class Question extends ArrayList<Answer> {

    /**
     * The question's text
     */
    private String text;

    /**
     * Constructs a new question using the specified text
     * @param text  The question's text
     */
    public Question(String text) {
        this.text = test;
    }

    /**
     * Returns this question's text
     */
    public String getText() {
        return text;
    }
}

回答类：

/**
 * Facilitates an answer
 */
public class Answer {

    /**
     * The answer's text
     */
    private String text;

    /**
     * Whether or not this answer is correct
     */
    private boolean correct;

    /**
     * Constructs a new answer using the specified settings
     * @param text          The text of this answer
     * @param correct       Whether or not this answer is correct
     */
    public Answer(String text, boolean correct) {
        this.text = text;
        this.correct = correct;
    }

    /**
     * Returns this answer's text
     */
    public String getText() {
        return text;
    }

    /**
     * Whether or not this answer is correct
     */
    public boolean isCorrect() {
        return correct;
    }
}

其用法如下：

// Create a new questionnaire
Questionnaire questionnaire = new Questionnaire("The awesome questionnaire");

// Create a question and add answers to it
Question question = new Question("How awesome is this questionnaire?");
question.add(new Answer("It's pretty awesome", false));
question.add(new Answer("It's really awesome", false));
question.add(new Answer("It's so awesome my mind blows off!", true));

// Add the question to the questionnaire
questionnaire.add(question);

迭代它非常容易：

// Iterate over the questions within the questionnaire
for(Question question : questionnaire) {
    // Print the question's text
    System.out.println(question.getText());

    // Go over each answer in this question
    for(Answer answer : question) {
        // Print the question's text
        System.out.println(answer.getText());
    }
}

您也可以只迭代它的一部分：

// Iterate over the third to fifth question
for (int questionIndex = 2; questionIndex < 5; questionIndex ++) {
    // Get the current question
    Question question = questionnaire.get(questionIndex);

    // Iterate over all of the answers
    for (int answerIndex = 0; answerIndex < question.size(); answerIndex++) {
        // Get the current answer
        Answer answer = question.get(answerIndex);
    }
}

使用您描述的格式将文件读取到模型中可以通过以下方式完成：

// Create a new questionnaire
Questionnaire questionnaire = new Questionnaire("My awesome questionnaire");

// Lets scan the file and load it up to the questionnaire
Scanner scanner = new Scanner(new File("myfile.txt"));

// Read lines from that file and split it into tokens
String line, tokens[];
int tokenIndex;
while (scanner.hasNextLine() && (line = scanner.nextLine()) != null) {
    tokens = line.split(",");

    // Create the question taking the first token as its text
    Question question = new Question(tokens[0]);

    // Go over the tokens, from the first index to the one before last
    for (tokenIndex = 1; tokenIndex < tokens.length-1; tokenIndex++) {
        // Add the incorrect answer to the question
        question.add(new Answer(tokens[tokenIndex], false));
    }

    // Add the last question (correct one)
    question.add(new Answer(tokens[tokenIndex],true));
}

// Tada! questionnaire is now a complete questionnaire.