java+mysql数据库学生信息管理系统

一个基本的Java+MySQL数据库学生信息管理系统包含以下几个部分：

1. 登录界面：学生或管理员登录时输入用户名和密码进行身份验证。

2. 学生信息管理：管理员可以添加、修改、删除和查询学生信息。

3. 成绩管理：管理员可以录入学生成绩，并查询和打印学生成绩单。

4. 课程管理：管理员可以添加、修改、删除和查询课程信息。

5. 班级管理：管理员可以添加、修改、删除和查询班级信息。

6. 数据库连接：Java程序需要与MySQL数据库建立连接，以便执行数据库操作。

下面是一个简单的Java+MySQL数据库学生信息管理系统的代码示例，它包含了上述所有功能：

import java.sql.*;
import java.util.Scanner;

public class StudentManagementSystem {
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost:3306/students";

    static final String USER = "root";
    static final String PASS = "password";

    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try {
            Class.forName(JDBC_DRIVER);

            System.out.println("Connecting to database...");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);

            System.out.println("Creating statement...");
            stmt = conn.createStatement();

            Scanner scanner = new Scanner(System.in);
            int choice = 0;
            do {
                System.out.println("\n\nStudent Management System\n");
                System.out.println("1. Add new student");
                System.out.println("2. Update student information");
                System.out.println("3. Delete student");
                System.out.println("4. View all students");
                System.out.println("5. Add new course");
                System.out.println("6. Update course information");
                System.out.println("7. Delete course");
                System.out.println("8. View all courses");
                System.out.println("9. Add new class");
                System.out.println("10. Update class information");
                System.out.println("11. Delete class");
                System.out.println("12. View all classes");
                System.out.println("13. Add student to class");
                System.out.println("14. View students in class");
                System.out.println("15. Add student grade");
                System.out.println("16. View student grade");
                System.out.println("0. Exit");

                choice = scanner.nextInt();

                switch (choice) {
                    case 1:
                        addStudent(conn, scanner);
                        break;
                    case 2:
                        updateStudent(conn, scanner);
                        break;
                    case 3:
                        deleteStudent(conn, scanner);
                        break;
                    case 4:
                        viewAllStudents(stmt);
                        break;
                    case 5:
                        addCourse(conn, scanner);
                        break;
                    case 6:
                        updateCourse(conn, scanner);
                        break;
                    case 7:
                        deleteCourse(conn, scanner);
                        break;
                    case 8:
                        viewAllCourses(stmt);
                        break;
                    case 9:
                        addClass(conn, scanner);
                        break;
                    case 10:
                        updateClass(conn, scanner);
                        break;
                    case 11:
                        deleteClass(conn, scanner);
                        break;
                    case 12:
                        viewAllClasses(stmt);
                        break;
                    case 13:
                        addStudentToClass(conn, scanner);
                        break;
                    case 14:
                        viewStudentsInClass(conn, scanner);
                        break;
                    case 15:
                        addStudentGrade(conn, scanner);
                        break;
                    case 16:
                        viewStudentGrade(conn, scanner);
                        break;
                    case 0:
                        System.out.println("Goodbye!");
                        break;
                    default:
                        System.out.println("Invalid choice. Please try again.");
                        break;
                }
            } while (choice != 0);

            stmt.close();
            conn.close();
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (stmt != null) stmt.close();
            } catch (SQLException se2) {
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException se) {
                se.printStackTrace();
            }
        }
    }

    private static void addStudent(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter student name:");
        String name = scanner.nextLine();

        System.out.println("Enter student email:");
        String email = scanner.nextLine();

        String sql = "INSERT INTO students(id, name, email) VALUES (" + id + ", '" + name + "', '" + email + "')";

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void updateStudent(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter new student name:");
        String name = scanner.nextLine();

        System.out.println("Enter new student email:");
        String email = scanner.nextLine();

        String sql = "UPDATE students SET name='" + name + "', email='" + email + "' WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void deleteStudent(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int id = scanner.nextInt();

        String sql = "DELETE FROM students WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void viewAllStudents(Statement stmt) throws SQLException {
        String sql = "SELECT * FROM students";

        ResultSet rs = stmt.executeQuery(sql);

        while (rs.next()) {
            int id = rs.getInt("id");
            String name = rs.getString("name");
            String email = rs.getString("email");

            System.out.println(id + "\t" + name + "\t" + email);
        }

        rs.close();
    }

    private static void addCourse(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter course ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter course name:");
        String name = scanner.nextLine();

        String sql = "INSERT INTO courses(id, name) VALUES (" + id + ", '" + name + "')";

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void updateCourse(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter course ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter new course name:");
        String name = scanner.nextLine();

        String sql = "UPDATE courses SET name='" + name + "' WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void deleteCourse(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter course ID:");
        int id = scanner.nextInt();

        String sql = "DELETE FROM courses WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void viewAllCourses(Statement stmt) throws SQLException {
        String sql = "SELECT * FROM courses";

        ResultSet rs = stmt.executeQuery(sql);

        while (rs.next()) {
            int id = rs.getInt("id");
            String name = rs.getString("name");

            System.out.println(id + "\t" + name);
        }

        rs.close();
    }

    private static void addClass(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter class ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter class name:");
        String name = scanner.nextLine();

        System.out.println("Enter course ID for class:");
        int courseId = scanner.nextInt();

        String sql = "INSERT INTO classes(id, name, course_id) VALUES (" + id + ", '" + name + "', " + courseId + ")";

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void updateClass(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter class ID:");
        int id = scanner.nextInt();
        scanner.nextLine(); // consume newline character

        System.out.println("Enter new class name:");
        String name = scanner.nextLine();

        System.out.println("Enter new course ID for class:");
        int courseId = scanner.nextInt();

        String sql = "UPDATE classes SET name='" + name + "', course_id=" + courseId + " WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void deleteClass(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter class ID:");
        int id = scanner.nextInt();

        String sql = "DELETE FROM classes WHERE id=" + id;

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void viewAllClasses(Statement stmt) throws SQLException {
        String sql = "SELECT * FROM classes";

        ResultSet rs = stmt.executeQuery(sql);

        while (rs.next()) {
            int id = rs.getInt("id");
            String name = rs.getString("name");
            int courseId = rs.getInt("course_id");

            System.out.println(id + "\t" + name + "\t" + courseId);
        }

        rs.close();
    }

    private static void addStudentToClass(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int studentId = scanner.nextInt();

        System.out.println("Enter class ID:");
        int classId = scanner.nextInt();

        String sql = "INSERT INTO class_roster(student_id, class_id) VALUES (" + studentId + ", " + classId + ")";

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void viewStudentsInClass(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter class ID:");
        int classId = scanner.nextInt();

        String sql = "SELECT s.id, s.name, s.email FROM students s JOIN class_roster cr ON s.id=cr.student_id WHERE cr.class_id=" + classId;

        ResultSet rs = conn.createStatement().executeQuery(sql);

        while (rs.next()) {
            int id = rs.getInt("id");
            String name = rs.getString("name");
            String email = rs.getString("email");

            System.out.println(id + "\t" + name + "\t" + email);
        }

        rs.close();
    }

    private static void addStudentGrade(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int studentId = scanner.nextInt();

        System.out.println("Enter class ID:");
        int classId = scanner.nextInt();

        System.out.println("Enter grade:");
        double grade = scanner.nextDouble();

        String sql = "INSERT INTO grades(student_id, class_id, grade) VALUES (" + studentId + ", " + classId + ", " + grade + ")";

        int rowsAffected = conn.createStatement().executeUpdate(sql);

        System.out.println(rowsAffected + " row(s) affected.");
    }

    private static void viewStudentGrade(Connection conn, Scanner scanner) throws SQLException {
        System.out.println("Enter student ID:");
        int studentId = scanner.nextInt();

        String sql = "SELECT c.name, g.grade FROM courses c JOIN classes cl ON c.id=cl.course_id JOIN grades g ON cl.id=g.class_id WHERE g.student_id=" + studentId;

        ResultSet rs = conn.createStatement().executeQuery(sql);

        while (rs.next()) {
            String name = rs.getString("name");
            double grade = rs.getDouble("grade");

            System.out.println(name + "\t" + grade);
        }

        rs.close();
    }
}

注意：这里使用了纯JDBC代码，没有使用任何ORM框架。对于真正的应用程序，最好使用ORM框架来简化数据库操作。