Java programming to implement random selection of test questions in the online examination system

Java programming implements random selection of test questions in the online examination system, requiring specific code examples

In modern education, using the Internet to conduct online examinations has become a common examination method one. In order to ensure the fairness and validity of the exam, the exam system needs to be able to randomly select test questions. This article will introduce how to use Java programming to implement random extraction of test questions in the online examination system, and provide specific code examples.

First, we need to prepare test question data. Suppose we already have a test question bank, which contains multiple test questions. Each test question has a unique ID, as well as the specific content and answer options of the test question. The test question bank can be a database table, an Excel file, or any other form of data source.

Next, we need to write Java code to implement random selection of test questions. We can define an Exam class to represent an exam, which contains a question collection and a question extraction method. The question set is used to store the extracted test questions, and the question extraction method is used to randomly select a certain number of test questions from the test question bank and add them to the question set.

The following is a sample code of the Exam class:

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class Exam {
    private List<Question> questions;

    public Exam() {
        this.questions = new ArrayList<>();
    }

    public void addQuestion(Question question) {
        questions.add(question);
    }

    public List<Question> getQuestions() {
        return questions;
    }

    public void generateQuestions(List<Question> questionBank, int num) {
        Random random = new Random();

        // 随机生成num个不重复的下标
        List<Integer> indexes = new ArrayList<>();
        int totalQuestions = questionBank.size();
        while (indexes.size() < num) {
            int index = random.nextInt(totalQuestions);
            if (!indexes.contains(index)) {
                indexes.add(index);
            }
        }

        // 根据随机下标抽取试题
        for (int index : indexes) {
            questions.add(questionBank.get(index));
        }
    }
}

class Question {
    private int id;
    private String content;
    private List<String> options;
    private String answer;

    // 省略构造方法和getter/setter方法
}

In the above code, the Exam class contains a collection of questions, and a generateQuestions method for extracting test questions. The generateQuestions method first generates a certain number of non-repeating random subscripts, then extracts test questions from the test question bank based on the random subscripts and adds them to the question set.

In order to test the effect of the above code, we can write a simple sample program:

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {
        List<Question> questionBank = new ArrayList<>();

        // 假设试题库中有5个试题
        questionBank.add(new Question(1, "问题1", List.of("选项1", "选项2", "选项3"), "A"));
        questionBank.add(new Question(2, "问题2", List.of("选项1", "选项2", "选项3"), "B"));
        questionBank.add(new Question(3, "问题3", List.of("选项1", "选项2", "选项3"), "C"));
        questionBank.add(new Question(4, "问题4", List.of("选项1", "选项2", "选项3"), "A"));
        questionBank.add(new Question(5, "问题5", List.of("选项1", "选项2", "选项3"), "B"));

        Exam exam = new Exam();
        exam.generateQuestions(questionBank, 3);

        List<Question> questions = exam.getQuestions();
        for (Question question : questions) {
            System.out.println("问题：" + question.getContent());
            System.out.println("选项：" + question.getOptions());
            System.out.println("答案：" + question.getAnswer());
            System.out.println();
        }
    }
}

Run the above sample program, we can see that 3 test questions are randomly selected from the output results.

Through the above example code, we can see that it is very simple to use Java programming to randomly extract test questions in the online examination system. Developers can modify and improve the above code according to actual needs to adapt to different examination systems. Through the random selection of test questions, the fairness and flexibility of the exam can be improved, and the convenience and efficiency of online exams can be provided.

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