使用MySQL数据库，建立一个模拟商店的数据库，数据库名为shop 在数据库中创建商品表goods，表结构如下： number（文本），name（文本），madeTime（日期），price（数字，双精度） 其中number为主键，表示商品编号。 往数据表随机写入30-50条数据。 编写程序，先查询出goods表中的数据，然后随机获取其中的10条记录，并计算出这10条记录price字段值的平均值，即平均价格，在控制台打印出10条记录和平均价格

以下是使用Java编写的示例代码来创建数据库和表，插入随机数据，并执行查询和计算平均价格的操作： ```java import java.sql.*; import java.util.ArrayList; import java.util.List; import java.util.Random; public class ShopDatabase { private static final String URL = "jdbc:mysql://localhost:3306/shop"; private static final String USERNAME = "your_username"; private static final String PASSWORD = "your_password"; public static void main(String[] args) { try { // 连接数据库 Connection connection = DriverManager.getConnection(URL, USERNAME, PASSWORD); // 创建商品表 createGoodsTable(connection); // 插入随机数据 insertRandomData(connection); // 查询商品表中的数据 List<Goods> goodsList = queryGoodsTable(connection); // 随机获取10条记录并计算平均价格 List<Goods> randomGoodsList = getRandomGoods(goodsList, 10); double averagePrice = calculateAveragePrice(randomGoodsList); // 打印10条记录和平均价格 System.out.println("随机获取的10条记录："); for (Goods goods : randomGoodsList) { System.out.println(goods); } System.out.println("平均价格：" + averagePrice); // 关闭数据库连接 connection.close(); } catch (SQLException e) { e.printStackTrace(); } } private static void createGoodsTable(Connection connection) throws SQLException { String createTableQuery = "CREATE TABLE IF NOT EXISTS goods (" + "number VARCHAR(255) PRIMARY KEY," + "name VARCHAR(255)," + "madeTime DATE," + "price DOUBLE)"; Statement statement = connection.createStatement(); statement.execute(createTableQuery); statement.close(); } private static void insertRandomData(Connection connection) throws SQLException { String insertQuery = "INSERT INTO goods (number, name, madeTime, price) VALUES (?, ?, ?, ?)"; PreparedStatement statement = connection.prepareStatement(insertQuery); Random random = new Random(); int numOfData = random.nextInt(21) + 30; // 生成30-50之间的随机数 for (int i = 1; i <= numOfData; i++) { statement.setString(1, "G" + i); statement.setString(2, "商品" + i); statement.setDate(3, new Date(System.currentTimeMillis())); statement.setDouble(4, random.nextDouble() * 100); statement.executeUpdate(); } statement.close(); } private static List<Goods> queryGoodsTable(Connection connection) throws SQLException { String query = "SELECT * FROM goods"; Statement statement = connection.createStatement(); ResultSet resultSet = statement.executeQuery(query); List<Goods> goodsList = new ArrayList<>(); while (resultSet.next()) { String number = resultSet.getString("number"); String name = resultSet.getString("name"); Date madeTime = resultSet.getDate("madeTime"); double price = resultSet.getDouble("price"); Goods goods = new Goods(number, name, madeTime, price); goodsList.add(goods); } resultSet.close(); statement.close(); return goodsList; } private static List<Goods> getRandomGoods(List<Goods> goodsList, int num) { List<Goods> randomGoodsList = new ArrayList<>(); Random random = new Random(); int size = goodsList.size(); if (size <= num) { return goodsList; } for (int i = 0; i < num; i++) { int randomIndex = random.nextInt(size); randomGoodsList.add(goodsList.get(randomIndex)); } return randomGoodsList; } private static double calculateAveragePrice(List<Goods> goodsList) { double sum = 0; for (Goods goods : goodsList) { sum += goods.getPrice(); } return sum / goodsList.size(); } } class Goods { private String number; private String name; private Date madeTime; private double price; public Goods(String number, String name, Date madeTime, double price) { this.number = number; this.name = name; this.madeTime = madeTime; this.price = price; } public String getNumber() { return number; } public String getName() { return name; } public Date getMadeTime() { return madeTime; } public double getPrice() { return price; } @Override public String toString() { return "商品编号：" + number + ", 商品名称：" + name + ", 生产日期：" + madeTime + ", 价格：" + price; } } ``` 请将`your_username`和`your_password`替换为您的MySQL用户名和密码。该代码首先创建一个名为`shop`的数据库，然后在该数据库中创建名为`goods`的商品表，并插入30-50条随机数据。接下来，它查询商品表中的数据，并随机选择10条记录。最后，它计算这10条记录的平均价格，并将10条记录和平均价格打印到控制台上。 请确保您已经正确安装了MySQL数据库，并将Java代码中的数据库连接参数替换为您自己的数据库连接参数。