查看本章节

查看作业目录

---

需求说明：

模拟网上商城购物，当用户选好物品提交订单时，每笔订单会自动生成一个唯一的订单编号。而部分电子商务网站在数据高峰期时，一毫秒可能需要处理近千笔的订单

现在简单模拟 5 个订单同时提交，生成唯一订单编号的场景。订单编号的生成规则是以毫秒为单位的当前时间＋订单序号

例如，当前时间的毫秒数是 150000，那第 1 笔订单的编号就是 1500001，第 9 笔订单的编号就是 1500009

实现思路：

项目中创建订单类 Order（订单编号、订单金额、下单用户）

创建订单处理类 ProcessOrder实现Runnable接口，定义Order类型的成员变量和一个Integer静态count作为订单序号（初始1），同时添加产生订单号的方法

产生订单号方法中使用sleep延迟500毫秒，同时添加同步代码块，指定静态变量 count 为同步监视器，同步代码块内则采用系统时间毫秒和订单序号生成订单号操作

在同步代码块外，把订单用户、订单金额和订单编号打印输出

创建测试启动类 TestOrder。在该类的 main() 方法内，使用有参构造方法实例化 5 个 Order 对象。使用ProcessOrder(Order order) 构造方法，实例化 5 个 ProcessOrder 类的对象，并把 5 个 Order 对象依次传给构造方法的参数 order。分别创建5个Thread对象依次传入5个ProcessOrder，启动测试

实现代码：

订单类（Order）

public class Order {

	//订单编号

	private String orderNumber;

	//订单金额

	private double orderAmount;

	//用户名称

	private String username;

	//无参构造

	public Order() {

		super();

	}

	//有参构造

	public Order(String orderNumber, double orderAmount, String username) {

		super();

		this.orderNumber = orderNumber;

		this.orderAmount = orderAmount;

		this.username = username;

	}

	public String getOrderNumber() {

		return orderNumber;

	}

	public void setOrderNumber(String orderNumber) {

		this.orderNumber = orderNumber;

	}

	public double getOrderAmount() {

		return orderAmount;

	}

	public void setOrderAmount(double orderAmount) {

		this.orderAmount = orderAmount;

	}

	public String getUsername() {

		return username;

	}

	public void setUsername(String username) {

		this.username = username;

	}

}

订单处理类（ProcessOrder）

public class ProcessOrder implements Runnable{

	private Order order;

	//订单计数器

	private static Integer count = 1;

	public ProcessOrder(Order order) {

		this.order = order;

	}

	@Override

	public void run() {

		generateOrderNumber();

	}

	public void generateOrderNumber() {

		try {

			//加入线程延迟

			Thread.sleep(500);

		} catch (InterruptedException e) {

			e.printStackTrace();

		}

		//同步监听器是count变量

		synchronized (count) {

			//生成订单编号

			StringBuffer orderNumber = new StringBuffer("").append(System.currentTimeMillis()).append(count++);

			//将订单编号保存到订单对象中

			order.setOrderNumber(orderNumber.toString());

		}

		System.out.printf("%s的订单金额是%.2f元，订单编号是：%s\n",order.getUsername(),order.getOrderAmount(),order.getOrderNumber());

	}

}

启动运行类（TestOrder）

public class TestOrder {

	public static void main(String[] args) {

		//实例化5个订单对象

		Order order1 = new Order(null,300,"张三");

		Order order2 = new Order(null,400,"李四");

		Order order3 = new Order(null,500,"王五");

		Order order4 = new Order(null,300,"赵六");

		Order order5 = new Order(null,200,"秦七");

		//实例化5个Runnable对象

		ProcessOrder processOrder1 = new ProcessOrder(order1);

		ProcessOrder processOrder2 = new ProcessOrder(order2);

		ProcessOrder processOrder3 = new ProcessOrder(order3);

		ProcessOrder processOrder4 = new ProcessOrder(order4);

		ProcessOrder processOrder5 = new ProcessOrder(order5);

		//实例化5条线程

		Thread thread1 = new Thread(processOrder1);

		Thread thread2 = new Thread(processOrder2);

		Thread thread3 = new Thread(processOrder3);

		Thread thread4 = new Thread(processOrder4);

		Thread thread5 = new Thread(processOrder5);

		//依次启动线程

		thread1.start();

		thread2.start();

		thread3.start();

		thread4.start();

		thread5.start();

	}

}