How to use Java to implement the test paper classification function of the online examination system

How to use Java to implement the test paper classification function of the online examination system requires specific code examples

With the rapid development of information technology, more and more educational institutions are beginning to An online examination system is used for student examination assessment. The online examination system not only improves the efficiency and accuracy of examinations, but also reduces the workload of teachers. In a complete online examination system, examination paper classification is a very important part. It can help teachers better organize and manage examination papers and improve the efficiency of the examination process. This article will introduce how to use Java to implement the test paper classification function of the online examination system and provide specific code examples.

1. Design the database table structure for test paper classification
   The implementation of the test paper classification function first requires the design of the database table structure. In this example, we use the MySQL database and design the following table structure:

• tbl_exam table: stores all test paper information, including test paper ID, test paper name and other fields;
• tbl_category table: stores test paper classification information, including fields such as category ID and category name;
• tbl_exam_category table: stores the relationship between test papers and categories, including fields such as test paper ID and category ID.

2. Writing Java classes for database operations
   In Java projects, we usually use Java Database Connection (JDBC) to operate the database. First, we need to write a JDBC tool class to connect to the database and execute SQL statements. The following is a sample code of a simple JDBC tool class:

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class JDBCUtils {
    private static final String DATABASE_URL = "jdbc:mysql://localhost:3306/examdb";
    private static final String DATABASE_USERNAME = "root";
    private static final String DATABASE_PASSWORD = "root";

    public static Connection getConnection() {
        Connection connection = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            connection = DriverManager.getConnection(DATABASE_URL, DATABASE_USERNAME, DATABASE_PASSWORD);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
        return connection;
    }

    public static void closeConnection(Connection connection, PreparedStatement statement, ResultSet resultSet) {
        try {
            if (resultSet != null) {
                resultSet.close();
            }
            if (statement != null) {
                statement.close();
            }
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Next, we write a Java class for test paper classification, including the following methods:

• Add test paper classification : Insert a new category record into the tbl_category table in the database based on the category name.

public class CategoryDao {
    public void addCategory(String categoryName) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = JDBCUtils.getConnection();
            String sql = "INSERT INTO tbl_category (name) VALUES (?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1, categoryName);
            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeConnection(connection, statement, null);
        }
    }
}

• Add the relationship between test paper category and test paper: insert a new relationship record into the tbl_exam_category table based on the test paper ID and category ID.

public class ExamCategoryDao {
    public void addExamCategory(int examId, int categoryId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = JDBCUtils.getConnection();
            String sql = "INSERT INTO tbl_exam_category (exam_id, category_id) VALUES (?, ?)";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, examId);
            statement.setInt(2, categoryId);
            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.closeConnection(connection, statement, null);
        }
    }
}

3. Write test code
   Write test code and call the above method to test the implementation of the test paper classification function.

public class Test {
    public static void main(String[] args) {
        CategoryDao categoryDao = new CategoryDao();
        ExamCategoryDao examCategoryDao = new ExamCategoryDao();

        // 添加试卷分类
        categoryDao.addCategory("数学");
        categoryDao.addCategory("英语");
        categoryDao.addCategory("物理");

        // 添加试卷分类和试卷的关系
        examCategoryDao.addExamCategory(1, 1); // 将试卷1分类为数学
        examCategoryDao.addExamCategory(2, 2); // 将试卷2分类为英语
        examCategoryDao.addExamCategory(3, 3); // 将试卷3分类为物理
    }
}

The above is a specific code example that uses Java to implement the test paper classification function of the online examination system. Through these codes, we can classify the test papers and record them in the database. Teachers can better organize and manage test papers based on the information on test paper classification, and improve the efficiency of the examination process. Of course, this is only a partial example of the test paper classification function. In actual applications, there may be other more complex functions that need to be designed and implemented according to specific needs.

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