import java.sql.*;
import java.util.Scanner;public class StudentManagementSystem {private static final String URL = "jdbc:mysql://localhost:3306/test";private static final String USER = "root";private static final String PASSWORD = "root";public static void main(String[] args) {Scanner scanner = new Scanner(System.in);String input;System.out.println("\n欢迎使用学生管理系统，请登录：");while (!login(scanner)) {}do {System.out.println("\n学生管理系统");System.out.println("1. 增加学生");System.out.println("2. 删除学生");System.out.println("3. 修改学生信息");System.out.println("4. 查询学生信息");System.out.println("5. 浏览所有学生");System.out.println("0. 退出");System.out.print("请选择操作: ");input = scanner.nextLine();switch (input) {case "1":addStudent(scanner);break;case "2":deleteStudent(scanner);break;case "3":updateStudent(scanner);break;case "4":searchStudent(scanner);break;case "5":listStudents(scanner);break;case "0":System.out.println("退出系统");break;default:System.out.println("无效的输入，请重新选择。");}} while (!input.equals("0"));scanner.close();}private static boolean login(Scanner scanner) {System.out.print("请输入用户名: ");String username = scanner.nextLine();System.out.print("请输入密码: ");String password = scanner.nextLine();if ("root".equals(username) && "root".equals(password)) {System.out.println("登录成功！");return true;} else {System.out.println("用户名或密码错误！");return false;}}// 增加学生信息private static void addStudent(Scanner scanner) {Connection conn = connectDatabase();if (conn != null) {try {System.out.print("输入学生姓名: ");String name = scanner.nextLine();System.out.print("输入学生年龄: ");int age = Integer.parseInt(scanner.nextLine());System.out.print("输入学生年级: ");String grade = scanner.nextLine();String sql = "INSERT INTO students (name, age, grade) VALUES (?, ?, ?)";try (PreparedStatement stmt = conn.prepareStatement(sql)) {stmt.setString(1, name);stmt.setInt(2, age);stmt.setString(3, grade);int rowsAffected = stmt.executeUpdate();if (rowsAffected > 0) {System.out.println("学生信息添加成功！");} else {System.out.println("添加失败！");}}} catch (SQLException e) {e.printStackTrace();} finally {closeConnection(conn);}}}// 删除学生信息private static void deleteStudent(Scanner scanner) {Connection conn = connectDatabase();if (conn != null) {try {System.out.print("输入要删除的学生ID: ");int id = Integer.parseInt(scanner.nextLine());String sql = "DELETE FROM students WHERE id = ?";try (PreparedStatement stmt = conn.prepareStatement(sql)) {stmt.setInt(1, id);int rowsAffected = stmt.executeUpdate();if (rowsAffected > 0) {System.out.println("学生信息删除成功！");} else {System.out.println("删除失败，可能该学生ID不存在！");}}} catch (SQLException e) {e.printStackTrace();} finally {closeConnection(conn);}}}// 修改学生信息private static void updateStudent(Scanner scanner) {Connection conn = connectDatabase();if (conn != null) {try {System.out.print("输入要修改的学生ID: ");int id = Integer.parseInt(scanner.nextLine());System.out.print("输入新的姓名: ");String name = scanner.nextLine();System.out.print("输入新的年龄: ");int age = Integer.parseInt(scanner.nextLine());System.out.print("输入新的年级: ");String grade = scanner.nextLine();String sql = "UPDATE students SET name = ?, age = ?, grade = ? WHERE id = ?";try (PreparedStatement stmt = conn.prepareStatement(sql)) {stmt.setString(1, name);stmt.setInt(2, age);stmt.setString(3, grade);stmt.setInt(4, id);int rowsAffected = stmt.executeUpdate();if (rowsAffected > 0) {System.out.println("学生信息更新成功！");} else {System.out.println("更新失败，可能该学生ID不存在！");}}} catch (SQLException e) {e.printStackTrace();} finally {closeConnection(conn);}}}// 查询学生信息private static void searchStudent(Scanner scanner) {Connection conn = connectDatabase();if (conn != null) {try {System.out.print("输入要查询的学生ID: ");int id = Integer.parseInt(scanner.nextLine());String sql = "SELECT * FROM students WHERE id = ?";try (PreparedStatement stmt = conn.prepareStatement(sql)) {stmt.setInt(1, id);ResultSet rs = stmt.executeQuery();if (rs.next()) {int studentId = rs.getInt("id");String studentName = rs.getString("name");int studentAge = rs.getInt("age");String studentGrade = rs.getString("grade");System.out.println("学生ID: " + studentId);System.out.println("姓名: " + studentName);System.out.println("年龄: " + studentAge);System.out.println("年级: " + studentGrade);} else {System.out.println("未找到该学生信息！");}}} catch (SQLException e) {e.printStackTrace();} finally {closeConnection(conn);}}}// 浏览所有学生信息private static void listStudents(Scanner scanner) {Connection conn = connectDatabase();if (conn != null) {try {String sql = "SELECT * FROM students";try (Statement stmt = conn.createStatement()) {ResultSet rs = stmt.executeQuery(sql);while (rs.next()) {int studentId = rs.getInt("id");String studentName = rs.getString("name");int studentAge = rs.getInt("age");String studentGrade = rs.getString("grade");System.out.println("学生ID: " + studentId + ", 姓名: " + studentName + ", 年龄: " + studentAge + ", 年级: " + studentGrade);}}} catch (SQLException e) {e.printStackTrace();} finally {closeConnection(conn);}}}// 连接数据库的方法private static Connection connectDatabase() {// 这里省略了异常处理和资源关闭，实际应用中需要添加try {return DriverManager.getConnection(URL, USER, PASSWORD);} catch (SQLException e) {e.printStackTrace();return null;}}// 断开数据库连接的方法private static void closeConnection(Connection connection) {// 这里省略了异常处理，实际应用中需要添加try {if (connection != null && !connection.isClosed()) {connection.close();}} catch (SQLException e) {e.printStackTrace();}}}