Spring Boot 应用案例：打造股票价格自动通知平台

// 股票价格通知服务
@Service
public class StockPriceNotificationService {
 
    private final EmailService emailService;
    private final UserRepository userRepository;
    private final StockRepository stockRepository;
 
    // 使用Spring依赖注入EmailService和数据仓库
    @Autowired
    public StockPriceNotificationService(EmailService emailService, UserRepository userRepository, StockRepository stockRepository) {
        this.emailService = emailService;
        this.userRepository = userRepository;
        this.stockRepository = stockRepository;
    }
 
    // 当股票价格变动超过设定阈值时，发送通知
    public void sendNotificationIfNeeded(String stockCode, double newPrice) {
        Stock stock = stockRepository.findByStockCode(stockCode)
                .orElseThrow(() -> new StockNotFoundException(stockCode));
 
        if (newPrice > stock.getAlertPrice()) {
            List<User> subscribedUsers = userRepository.findAllBySubscribedStocksContains(stockCode);
            String subject = "股票价格警告: " + stockCode;
            String content = "股票 " + stockCode + " 价格超过了设定的警告价格。当前价格: " + newPrice;
 
            subscribedUsers.forEach(user -> emailService.sendEmail(user.getEmail(), subject, content));
        }
    }
}

这个代码实例展示了如何在Spring Boot应用中创建一个服务来处理股票价格通知的逻辑。它使用了依赖注入来注入必要的服务（如EmailService和数据仓库），并提供了一个方法来在股票价格超过用户设定的警告价格时发送通知。这个例子简洁地展示了如何将业务逻辑和Spring框架集成在一起。