用Java编写一个包含三种设计模式一种体系结构的简单程序

好的，下面我会为您提供一个简单的Java程序，其中包含了工厂模式、观察者模式、单例模式以及分层体系结构。该程序实现了一个简单的订单处理系统，具体实现如下：

// 订单类
public class Order {
    private int orderId;
    private String customerName;
    private double totalPrice;

    public Order(int orderId, String customerName, double totalPrice) {
        this.orderId = orderId;
        this.customerName = customerName;
        this.totalPrice = totalPrice;
    }

    public int getOrderId() {
        return orderId;
    }

    public String getCustomerName() {
        return customerName;
    }

    public double getTotalPrice() {
        return totalPrice;
    }
}

// 订单处理器接口
public interface OrderHandler {
    void handle(Order order);
}

// 订单处理器实现类1
public class EmailOrderHandler implements OrderHandler {
    private static EmailOrderHandler instance = null;

    private EmailOrderHandler() {
    }

    public static EmailOrderHandler getInstance() {
        if (instance == null) {
            instance = new EmailOrderHandler();
        }
        return instance;
    }

    @Override
    public void handle(Order order) {
        // 发送邮件
        System.out.println("向客户 " + order.getCustomerName() + " 发送订单邮件，订单号为 " + order.getOrderId());
    }
}

// 订单处理器实现类2
public class SMSOrderHandler implements OrderHandler {
    private static SMSOrderHandler instance = null;

    private SMSOrderHandler() {
    }

    public static SMSOrderHandler getInstance() {
        if (instance == null) {
            instance = new SMSOrderHandler();
        }
        return instance;
    }

    @Override
    public void handle(Order order) {
        // 发送短信
        System.out.println("向客户 " + order.getCustomerName() + " 发送订单短信，订单号为 " + order.getOrderId());
    }
}

// 订单处理器工厂
public class OrderHandlerFactory {
    public static OrderHandler getOrderHandler(String handlerType) {
        if ("email".equalsIgnoreCase(handlerType)) {
            return EmailOrderHandler.getInstance();
        } else if ("sms".equalsIgnoreCase(handlerType)) {
            return SMSOrderHandler.getInstance();
        } else {
            throw new IllegalArgumentException("Unsupported handler type.");
        }
    }
}

// 订单管理器
public class OrderManager {
    private List<OrderHandler> orderHandlers;

    public OrderManager(List<OrderHandler> orderHandlers) {
        this.orderHandlers = orderHandlers;
    }

    public void placeOrder(Order order) {
        // 处理订单
        for (OrderHandler handler : orderHandlers) {
            handler.handle(order);
        }
    }
}

// 应用程序入口
public class Application {
    public static void main(String[] args) {
        // 创建订单处理器列表
        List<OrderHandler> handlers = new ArrayList<>();
        handlers.add(OrderHandlerFactory.getOrderHandler("email"));
        handlers.add(OrderHandlerFactory.getOrderHandler("sms"));

        // 创建订单管理器
        OrderManager orderManager = new OrderManager(handlers);

        // 创建订单
        Order order = new Order(1001, "张三", 1000.0);

        // 处理订单
        orderManager.placeOrder(order);
    }
}

在该程序中，工厂模式用于创建订单处理器，单例模式用于保证订单处理器实现类的唯一性，观察者模式用于实现订单处理器的通知机制，分层体系结构用于将程序分解为多个模块以实现松耦合。该程序可以根据客户需求自动发送订单邮件或短信，实现了订单处理的自动化和个性化。