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How to design a system that supports multiple users answering questions online

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Sep 25, 2023 pm 02:39 PM

designmulti-user systemAnswer questions online

How to design a system that supports multiple users answering questions online

How to design a system that supports multi-user online answering requires specific code examples

With the development of the Internet, the demand for online learning and online exams is increasing . A system that supports multi-user online question answering can effectively meet the needs of users and provide convenient learning and examination methods. This article will introduce how to design a system that supports multi-user online question answering and provide specific code examples.

1. System design

Functional requirements
A system that supports multi-user registration, login and management. Users can create, edit and delete their own question sets, and other users can Participate in answering questions, and the system can automatically score.
Technology Selection
Using Web development technology, the front end uses HTML, CSS and JavaScript to implement the user interface, and the back end uses Java and MySQL to implement system functions.
Database Design
Create the following tables: user table, question set table and question table. The user table includes fields such as user ID, user name, and password; the question set table includes fields such as question set ID, created user ID, and name; the question table includes fields such as question ID, question set ID, question content, and answers.

2. System Implementation

Front-end Implementation
The user registration and login pages are designed using HTML and CSS, and JavaScript is used to implement user interaction functions. For example, users can submit registration information through a form, and login verification can be performed through AJAX asynchronous requests.
Back-end implementation
Use Java language to implement back-end logic, and use Tomcat as the web server.

a. User management module
Design the user entity class User, including user ID, user name, password and other fields. Use MySQL database to save user information.

b. Question set management module
Design the question set entity class QuestionSet, including question set ID, creation user ID, name and other fields. Use MySQL database to save question set information.

c. Question management module
Design the question entity class Question, including fields such as question ID, question set ID, question content and answer. Use MySQL database to save question information.

d. Answering and scoring module
Design the answer record entity class AnswerRecord, including fields such as record ID, user ID, question ID, answer and score. Use MySQL database to save answer record information.

Database operation
Use JDBC technology to realize the addition, deletion, modification and query functions of the database. Write SQL statements in Java code to perform corresponding database operations.

3. Code Example

The following is a simple code example that demonstrates the user registration and login functions.

User registration page (register.html)

<!DOCTYPE html>
<html>
<head>
    <title>User Registration</title>
    <script>
        function register() {
            // 获取用户输入的注册信息
            var username = document.getElementById("username").value;
            var password = document.getElementById("password").value;
            
            // 发送AJAX请求进行注册
            var xhr = new XMLHttpRequest();
            xhr.open("POST", "/register", true);
            xhr.setRequestHeader("Content-Type", "application/json");
            
            xhr.onreadystatechange = function() {
                if (xhr.readyState == 4 && xhr.status == 200) {
                    var response = JSON.parse(xhr.responseText);
                    if (response.success) {
                        alert("Registration successful!");
                    } else {
                        alert("Registration failed: " + response.message);
                    }
                }
            };
            
            var data = JSON.stringify({"username": username, "password": password});
            xhr.send(data);
        }
    </script>
</head>
<body>
    <h1 id="User-Registration">User Registration</h1>
    <form>
        Username: <input type="text" id="username"><br>
        Password: <input type="password" id="password"><br>
        <button type="button" onclick="register()">Register</button>
    </form>
</body>
</html>

User registration background processing (RegisterServlet.java)

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class RegisterServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        
        User user = new User(username, password);
        boolean success = UserDAO.register(user);
        
        response.setContentType("application/json");
        PrintWriter out = response.getWriter();
        out.print("{"success":" + success + "}");
        out.flush();
    }
}

Above The code is just a simple example, the implementation of the actual system requires more functions and details. Through the above design and code examples, we can initially implement a system that supports multi-user online question answering to help users improve learning and exam efficiency.

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