Using Java to build the examination result query function of the online examination system

Using Java to build the exam result query function of the online exam system

With the development of modern education, more and more schools and institutions have begun to use online exam systems to have a test. The online exam system provides candidates with a convenient and fast way to take exams, and can obtain exam results in real time. Among them, the test result inquiry function is a very important function in the online examination system. It allows candidates to check their scores in time after the test is over and understand their test performance.

This article will use Java language as an example to introduce how to use Java to build the examination result query function of the online examination system, and provide specific code examples.

1. Build database table structure

First, we need to build a database table to store exam results. The test results table contains at least fields such as candidate ID, test subjects, and test scores. In the MySQL database, you can use the following SQL statement to create the exam results table:

CREATE TABLE exam_results (
    id INT AUTO_INCREMENT PRIMARY KEY,
    student_id INT NOT NULL,
    subject VARCHAR(50) NOT NULL,
    score INT NOT NULL,
    exam_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

2. Create Java entity class

In Java, we need to create a corresponding exam result The entity class of the table. The fields in the entity class are consistent with the fields in the database table and provide corresponding getter and setter methods. The following is a sample code for a simple exam result entity class:

public class ExamResult {
    private int id;
    private int studentId;
    private String subject;
    private int score;
    private Date examTime;
    
    // 省略getter和setter方法
}

3. Writing query method

Next, we need to write a method to query exam results in the Java program . This method requires connecting to the database, executing SQL query statements, and converting the query results into a list of exam result objects. The following is a sample code for a simple query method:

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class ExamResultDao {
    // JDBC连接信息
    private static final String JDBC_URL = "jdbc:mysql://localhost:3306/exam_system";
    private static final String JDBC_USERNAME = "root";
    private static final String JDBC_PASSWORD = "password";
    
    // 查询考试结果的方法
    public List<ExamResult> queryExamResults(int studentId) {
        List<ExamResult> examResults = new ArrayList<>();
        
        try (Connection conn = DriverManager.getConnection(JDBC_URL, JDBC_USERNAME, JDBC_PASSWORD);
             Statement stmt = conn.createStatement()) {
            String sql = "SELECT * FROM exam_results WHERE student_id = " + studentId;
            ResultSet rs = stmt.executeQuery(sql);
            
            while (rs.next()) {
                ExamResult examResult = new ExamResult();
                examResult.setId(rs.getInt("id"));
                examResult.setStudentId(rs.getInt("student_id"));
                examResult.setSubject(rs.getString("subject"));
                examResult.setScore(rs.getInt("score"));
                examResult.setExamTime(rs.getTimestamp("exam_time"));
                examResults.add(examResult);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        
        return examResults;
    }
}

4. Calling the query method

Finally, we can call the query method in the interface of the examination system so that candidates can query own test scores. The following is a simple calling example:

public class ExamSystem {
    public static void main(String[] args) {
        ExamResultDao examResultDao = new ExamResultDao();
        List<ExamResult> examResults = examResultDao.queryExamResults(1001);
        
        for (ExamResult examResult : examResults) {
            System.out.println("考试科目：" + examResult.getSubject());
            System.out.println("考试成绩：" + examResult.getScore());
            System.out.println("考试时间：" + examResult.getExamTime());
            System.out.println("--------------------");
        }
    }
}

Through the above steps, we can realize the examination result query function of the online examination system. Candidates only need to enter their student number or other identity information to get their test scores. Of course, the above example is just a simple example, and issues such as security and performance also need to be considered in actual applications.

To sum up, using Java to build the exam results query function of the online exam system requires completing the following steps: building a database table structure, creating a Java entity class, writing query methods, and calling query methods. These steps can help us implement a simple but powerful examination results query function. Hope this article is helpful to you!

The above is the detailed content of Using Java to build the examination result query function of the online examination system. For more information, please follow other related articles on the PHP Chinese website!