实现一个商品信息管理的原型系统，具有增删查改等基本功能,必须以Java语言实现。可以是字符界面或者图形 界面。 实验的完整步骤应该是首先创建数据库(可以参考教材398，399，407页的代码)，然后编写程序。 任务描述: 首先创建一个名为webstore的数据库然后创建一张名为products的表然后可以手工往表里添加若干记录有了数据库和数据作为基础，可以开始如下实验： 功能需求描述:系统启动后显示如下字符界面的系统菜单(菜单宽度没有严格限制): ********请选择菜单********* * 1

好的，这是一个比较完整的Java实现商品信息管理系统的示例代码，包括了数据库创建、表创建、数据添加、增删查改等基本功能。界面采用字符界面。

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

public class ProductManager {

    private static final String URL = "jdbc:mysql://localhost:3306/";
    private static final String DB_NAME = "webstore";
    private static final String DRIVER = "com.mysql.jdbc.Driver";
    private static final String USER_NAME = "root";
    private static final String PASSWORD = "password";

    private static final String CREATE_DB_SQL = "CREATE DATABASE IF NOT EXISTS " + DB_NAME + " CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci";
    private static final String CREATE_TABLE_SQL = "CREATE TABLE IF NOT EXISTS products (id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(50), price DOUBLE)";
    private static final String INSERT_SQL = "INSERT INTO products (name, price) VALUES (?, ?)";
    private static final String SELECT_ALL_SQL = "SELECT * FROM products";
    private static final String SELECT_ONE_SQL = "SELECT * FROM products WHERE id = ?";
    private static final String UPDATE_SQL = "UPDATE products SET name = ?, price = ? WHERE id = ?";
    private static final String DELETE_SQL = "DELETE FROM products WHERE id = ?";

    private Scanner scanner;
    private Connection connection;
    private PreparedStatement insertStatement;
    private PreparedStatement selectOneStatement;
    private PreparedStatement updateStatement;
    private PreparedStatement deleteStatement;

    public ProductManager() {
        scanner = new Scanner(System.in);
        try {
            Class.forName(DRIVER);
            connection = DriverManager.getConnection(URL + DB_NAME, USER_NAME, PASSWORD);
            createDatabase();
            createTable();
            insertStatement = connection.prepareStatement(INSERT_SQL);
            selectOneStatement = connection.prepareStatement(SELECT_ONE_SQL);
            updateStatement = connection.prepareStatement(UPDATE_SQL);
            deleteStatement = connection.prepareStatement(DELETE_SQL);
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }

    private void createDatabase() throws SQLException {
        Statement statement = connection.createStatement();
        statement.execute(CREATE_DB_SQL);
        statement.close();
    }

    private void createTable() throws SQLException {
        Statement statement = connection.createStatement();
        statement.execute(CREATE_TABLE_SQL);
        statement.close();
    }

    private void printMenu() {
        System.out.println("********请选择菜单*********");
        System.out.println("* 1.添加商品信息             *");
        System.out.println("* 2.查询所有商品信息         *");
        System.out.println("* 3.查询单个商品信息         *");
        System.out.println("* 4.修改商品信息             *");
        System.out.println("* 5.删除商品信息             *");
        System.out.println("* 0.退出系统                 *");
        System.out.println("*****************************");
    }

    private void addProduct() throws SQLException {
        System.out.println("请输入商品名称：");
        String name = scanner.nextLine();
        System.out.println("请输入商品价格：");
        double price = Double.parseDouble(scanner.nextLine());
        insertStatement.setString(1, name);
        insertStatement.setDouble(2, price);
        int result = insertStatement.executeUpdate();
        if (result > 0) {
            System.out.println("添加商品信息成功！");
        } else {
            System.out.println("添加商品信息失败！");
        }
    }

    private void listAllProducts() throws SQLException {
        Statement statement = connection.createStatement();
        ResultSet resultSet = statement.executeQuery(SELECT_ALL_SQL);
        System.out.println("所有商品信息如下：");
        System.out.println("编号\t名称\t价格");
        while (resultSet.next()) {
            int id = resultSet.getInt("id");
            String name = resultSet.getString("name");
            double price = resultSet.getDouble("price");
            System.out.println(id + "\t" + name + "\t" + price);
        }
        statement.close();
    }

    private void queryProduct() throws SQLException {
        System.out.println("请输入要查询的商品编号：");
        int id = Integer.parseInt(scanner.nextLine());
        selectOneStatement.setInt(1, id);
        ResultSet resultSet = selectOneStatement.executeQuery();
        if (resultSet.next()) {
            String name = resultSet.getString("name");
            double price = resultSet.getDouble("price");
            System.out.println("编号\t名称\t价格");
            System.out.println(id + "\t" + name + "\t" + price);
        } else {
            System.out.println("没有找到该商品信息！");
        }
    }

    private void updateProduct() throws SQLException {
        System.out.println("请输入要修改的商品编号：");
        int id = Integer.parseInt(scanner.nextLine());
        selectOneStatement.setInt(1, id);
        ResultSet resultSet = selectOneStatement.executeQuery();
        if (resultSet.next()) {
            String name = resultSet.getString("name");
            double price = resultSet.getDouble("price");
            System.out.println("请输入新的商品名称（原来的名称为：" + name + "）：");
            String newName = scanner.nextLine();
            System.out.println("请输入新的商品价格（原来的价格为：" + price + "）：");
            double newPrice = Double.parseDouble(scanner.nextLine());
            updateStatement.setString(1, newName);
            updateStatement.setDouble(2, newPrice);
            updateStatement.setInt(3, id);
            int result = updateStatement.executeUpdate();
            if (result > 0) {
                System.out.println("修改商品信息成功！");
            } else {
                System.out.println("修改商品信息失败！");
            }
        } else {
            System.out.println("没有找到该商品信息！");
        }
    }

    private void deleteProduct() throws SQLException {
        System.out.println("请输入要删除的商品编号：");
        int id = Integer.parseInt(scanner.nextLine());
        deleteStatement.setInt(1, id);
        int result = deleteStatement.executeUpdate();
        if (result > 0) {
            System.out.println("删除商品信息成功！");
        } else {
            System.out.println("删除商品信息失败！");
        }
    }

    public void run() throws SQLException {
        while (true) {
            printMenu();
            System.out.println("请输入菜单编号：");
            int choice = Integer.parseInt(scanner.nextLine());
            switch (choice) {
                case 1:
                    addProduct();
                    break;
                case 2:
                    listAllProducts();
                    break;
                case 3:
                    queryProduct();
                    break;
                case 4:
                    updateProduct();
                    break;
                case 5:
                    deleteProduct();
                    break;
                case 0:
                    System.out.println("谢谢使用，再见！");
                    return;
                default:
                    System.out.println("输入的菜单编号不正确，请重新输入！");
                    break;
            }
        }
    }

    public static void main(String[] args) throws SQLException {
        ProductManager manager = new ProductManager();
        manager.run();
    }
}

注意，这里的代码仅仅是一个示例，实际操作中可能还需要进行更多的异常处理和边界条件判断。同时，这里只是采用了字符界面来实现，如果需要图形界面可以使用Swing或JavaFX等GUI框架。