编写一个学生成绩管理系统的java代码，并将学生成绩存入数据库

以下是一个简单的Java代码示例，演示如何管理学生成绩并将其存储在MySQL数据库中。请注意，这只是一个示例，你可以根据自己的需要进行修改和扩展。

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

public class StudentGradeManagementSystem {

    private static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase";
    private static final String DB_USER = "root";
    private static final String DB_PASSWORD = "mypassword";

    public static void main(String[] args) {
        try (Connection conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWORD);
             Statement stmt = conn.createStatement()) {
            createTable(stmt);
            Scanner scanner = new Scanner(System.in);
            while (true) {
                System.out.println("1. Add student grade");
                System.out.println("2. View student grades");
                System.out.println("3. Exit");
                System.out.print("Enter your choice: ");
                int choice = scanner.nextInt();
                switch (choice) {
                    case 1:
                        addStudentGrade(conn);
                        break;
                    case 2:
                        viewStudentGrades(stmt);
                        break;
                    case 3:
                        System.exit(0);
                        break;
                    default:
                        System.out.println("Invalid choice");
                }
            }
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }

    private static void createTable(Statement stmt) throws SQLException {
        String sql = "CREATE TABLE IF NOT EXISTS student_grades ("
                + "id INT NOT NULL AUTO_INCREMENT,"
                + "name VARCHAR(50) NOT NULL,"
                + "subject VARCHAR(50) NOT NULL,"
                + "grade INT NOT NULL,"
                + "PRIMARY KEY (id)"
                + ")";
        stmt.executeUpdate(sql);
    }

    private static void addStudentGrade(Connection conn) throws SQLException {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter student name: ");
        String name = scanner.nextLine();
        System.out.print("Enter subject: ");
        String subject = scanner.nextLine();
        System.out.print("Enter grade: ");
        int grade = scanner.nextInt();
        String sql = "INSERT INTO student_grades (name, subject, grade) VALUES (?, ?, ?)";
        try (PreparedStatement stmt = conn.prepareStatement(sql)) {
            stmt.setString(1, name);
            stmt.setString(2, subject);
            stmt.setInt(3, grade);
            int rowsAffected = stmt.executeUpdate();
            System.out.println(rowsAffected + " row(s) affected");
        }
    }

    private static void viewStudentGrades(Statement stmt) throws SQLException {
        String sql = "SELECT name, subject, grade FROM student_grades";
        try (ResultSet rs = stmt.executeQuery(sql)) {
            System.out.println("Name\tSubject\tGrade");
            while (rs.next()) {
                String name = rs.getString("name");
                String subject = rs.getString("subject");
                int grade = rs.getInt("grade");
                System.out.println(name + "\t" + subject + "\t" + grade);
            }
        }
    }
}

这个示例创建一个名为“student_grades”的表来存储学生成绩。它提供一个简单的菜单，允许用户添加新的学生成绩或查看已存储的学生成绩。它使用JDBC连接到MySQL数据库，并使用预处理语句执行INSERT和SELECT查询。你可以根据需要修改查询和表结构来满足你的需求。