用Java创建商品表，商品分类表、用户表和商品维护表，并插入信息

好的，我可以为您提供Java代码示例来创建这些表和插入信息。首先需要确保已经安装了Java开发环境和MySQL数据库，并且在MySQL数据库中创建了相应的数据库。

以下是Java代码示例：

import java.sql.*;

public class CreateTables {

    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost/";

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

    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;

        try {
            // 注册 JDBC 驱动器
            Class.forName(JDBC_DRIVER);

            // 打开一个连接
            System.out.println("连接到数据库...");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);

            // 创建数据库
            String sql = "CREATE DATABASE mydb";
            stmt = conn.createStatement();
            stmt.executeUpdate(sql);
            System.out.println("数据库已创建...");

            // 选择数据库
            conn = DriverManager.getConnection(DB_URL + "mydb", USER, PASS);

            // 创建商品分类表
            sql = "CREATE TABLE category " +
                    "(id INT NOT NULL AUTO_INCREMENT, " +
                    " name VARCHAR(255), " +
                    " PRIMARY KEY ( id ))";
            stmt.executeUpdate(sql);
            System.out.println("商品分类表已创建...");

            // 创建商品表
            sql = "CREATE TABLE product " +
                    "(id INT NOT NULL AUTO_INCREMENT, " +
                    " name VARCHAR(255), " +
                    " price DECIMAL(10,2), " +
                    " category_id INT, " +
                    " PRIMARY KEY ( id ), " +
                    " FOREIGN KEY (category_id) REFERENCES category(id))";
            stmt.executeUpdate(sql);
            System.out.println("商品表已创建...");

            // 创建用户表
            sql = "CREATE TABLE user " +
                    "(id INT NOT NULL AUTO_INCREMENT, " +
                    " name VARCHAR(255), " +
                    " email VARCHAR(255), " +
                    " password VARCHAR(255), " +
                    " PRIMARY KEY ( id ))";
            stmt.executeUpdate(sql);
            System.out.println("用户表已创建...");

            // 创建商品维护表
            sql = "CREATE TABLE product_maintenance " +
                    "(id INT NOT NULL AUTO_INCREMENT, " +
                    " product_id INT, " +
                    " user_id INT, " +
                    " maintenance_date DATE, " +
                    " description VARCHAR(255), " +
                    " PRIMARY KEY ( id ), " +
                    " FOREIGN KEY (product_id) REFERENCES product(id), " +
                    " FOREIGN KEY (user_id) REFERENCES user(id))";
            stmt.executeUpdate(sql);
            System.out.println("商品维护表已创建...");

            // 插入商品分类数据
            sql = "INSERT INTO category (name) VALUES " +
                    "('电脑'), " +
                    "('手机'), " +
                    "('家电')";
            stmt.executeUpdate(sql);
            System.out.println("商品分类数据已插入...");

            // 插入商品数据
            sql = "INSERT INTO product (name, price, category_id) VALUES " +
                    "('华为MateBook X Pro', 7999.00, 1), " +
                    "('iPhone 12 Pro', 8499.00, 2), " +
                    "('小米电视', 2799.00, 3)";
            stmt.executeUpdate(sql);
            System.out.println("商品数据已插入...");

            // 插入用户数据
            sql = "INSERT INTO user (name, email, password) VALUES " +
                    "('张三', 'zhangsan@example.com', 'password'), " +
                    "('李四', 'lisi@example.com', 'password'), " +
                    "('王五', 'wangwu@example.com', 'password')";
            stmt.executeUpdate(sql);
            System.out.println("用户数据已插入...");

            // 插入商品维护数据
            sql = "INSERT INTO product_maintenance (product_id, user_id, maintenance_date, description) VALUES " +
                    "(1, 1, '2020-01-01', '更换键盘'), " +
                    "(1, 2, '2020-02-01', '更换电池'), " +
                    "(2, 3, '2020-03-01', '更换屏幕')";
            stmt.executeUpdate(sql);
            System.out.println("商品维护数据已插入...");

            // 完成
            System.out.println("完成...");

        } catch (SQLException se) {
            // 处理 JDBC 错误
            se.printStackTrace();
        } catch (Exception e) {
            // 处理 Class.forName 错误
            e.printStackTrace();
        } finally {
            // 关闭资源
            try {
                if (stmt != null) stmt.close();
            } catch (SQLException se2) {
            }
            try {
                if (conn != null) conn.close();
            } catch (SQLException se) {
                se.printStackTrace();
            }
        }
    }
}

请注意，这只是一个示例，您可能需要根据您的需求修改表结构和插入数据的方式。