JSP(JavaServer Pages)是一种用于创建动态Web内容的Java技术。它允许开发者将Java代码嵌入到HTML页面中,从而实现动态网页的生成和交互。下面我将详细介绍JSP实现选课系统的基础概念、优势、类型、应用场景以及可能遇到的问题和解决方法。
CREATE TABLE students (
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(100),
email VARCHAR(100)
);
CREATE TABLE courses (
id INT PRIMARY KEY AUTO_INCREMENT,
name VARCHAR(100),
description TEXT
);
CREATE TABLE enrollments (
student_id INT,
course_id INT,
FOREIGN KEY (student_id) REFERENCES students(id),
FOREIGN KEY (course_id) REFERENCES courses(id)
);
<%@ page import="java.util.List" %>
<%@ page import="com.example.Course" %>
<html>
<head>
<title>Course List</title>
</head>
<body>
<h1>Available Courses</h1>
<ul>
<%
List<Course> courses = (List<Course>) request.getAttribute("courses");
for (Course course : courses) { %>
<li><a href="enroll?courseId=<%= course.getId() %>"><%= course.getName() %></a></li>
<% } %>
</ul>
</body>
</html>
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/courses")
public class CourseServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Course> courses = CourseDAO.getAllCourses();
request.setAttribute("courses", courses);
request.getRequestDispatcher("courseList.jsp").forward(request, response);
}
}
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class CourseDAO {
public static List<Course> getAllCourses() {
List<Course> courses = new ArrayList<>();
try {
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/dbname", "username", "password");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM courses");
while (rs.next()) {
Course course = new Course();
course.setId(rs.getInt("id"));
course.setName(rs.getString("name"));
course.setDescription(rs.getString("description"));
courses.add(course);
}
rs.close();
stmt.close();
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
return courses;
}
}
通过以上步骤和示例代码,你可以构建一个基本的选课系统。如果有更具体的问题或需要进一步的帮助,请提供详细信息。
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