目的
效率型设计模式, 意义在于不阻塞主流程的同时完成异步操作, 比如发邮件短信, 完成耗时的任务等
例子代码
最近丰巢收费 5 毛的事件引起了业主和物业的强烈反对, 5 毛钱其实也不是很多, 掉地上有人都不看一眼的, 也就我们这种中年男人才会捡起来揣兜里, 我们先来看看没有丰巢的时候我们的快递其实是比较不方便的, 我们假设快递物品必须要交到收货人手里, 不然可能会有丢失风险.
先定义一个货物类:
@Data@AllArgsConstructor//货物public class Good { private String name;}
比如我们定义一个消费者:
@Data@AllArgsConstructor//'消费者'public class Consumer { private String name; public void receiveGood(List<Good> goodList) { back2Home(); System.out.println(name + "收到了" + goodList.toString()); } //返回家中 @SneakyThrows private void back2Home() { Thread.sleep(1000); }}
定义一个快递小哥类:
@Data@AllArgsConstructor//快递员public class Courier { private String name; public void sendGood(Consumer consumer, List<Good> goodList) { consumer.receiveGood(goodList); }}
快递交个得等每个顾客回家才能给下一个人送快递:
StopWatch stopwatch = StopWatch.createStarted();final Map<Consumer, List<Good>> DELIVERY_INFO_MAP = new HashMap<>();DELIVERY_INFO_MAP.put(new Consumer("杰克马"), Arrays.asList(new Good("螃蟹"), new Good("河马")));DELIVERY_INFO_MAP.put(new Consumer("奶茶妹妹"), Arrays.asList(new Good("奶茶")));DELIVERY_INFO_MAP.put(new Consumer("小马哥"), Arrays.asList(new Good("肌肉")));Courier courier = new Courier("脸盲东");DELIVERY_INFO_MAP.forEach((k,v) -> { courier.sendGood(k,v);});stopwatch.stop();System.out.println("total time: " + stopwatch.getTime(TimeUnit.SECONDS));
输出:
杰克马收到了[Good(name=螃蟹), Good(name=河马)]奶茶妹妹收到了[Good(name=奶茶)]小马哥收到了[Good(name=肌肉)]total time: 3
问题分析
快递小哥得等每个 '消费者' 回到家取快递, 太浪费时间了, 对顾客也不友好, 还得必须回到家取快递
丰巢模式(生产者消费者模式)
先定义一个消息(货物):
@Datapublic class EventItem<T> { private EventItemType eventType; private String eventId; private LocalDateTime eventDateTime; private T eventValue;}
先定义一个丰巢(消息队列):
public class ItemQueue { private BlockingQueue<EventItem> queue = new LinkedBlockingQueue<>(50); public void put(EventItem item) { try { queue.put(item); } catch (InterruptedException e) { throw new RuntimeException("put item to queue failed"); } } public EventItem take() { try { return queue.take(); } catch (InterruptedException e) { throw new RuntimeException("put item to queue failed"); } }}
再定义一个生产者:
public class ItemProducer { private ItemQueue itemQueue; public ItemProducer(ItemQueue itemQueue) { this.itemQueue = itemQueue; } public <T> void generateEvent(EventItemType eventItemType, T value) { EventItem<T> eventItem = new EventItem<>(); eventItem.setEventDateTime(LocalDateTime.now()); eventItem.setEventId(UUID.randomUUID().toString()); eventItem.setEventValue(value); eventItem.setEventType(eventItemType); itemQueue.put(eventItem); }}
再定义一个生产者:
public class ItemConsumer { private ItemQueue itemQueue; private EnumMap<EventItemType, ItemHander> typeItemHander; public ItemConsumer(ItemQueue itemQueue, EnumMap<EventItemType, ItemHander> typeItemHander) { this.itemQueue = itemQueue; this.typeItemHander = typeItemHander; } public void handleEvent() { EventItem eventItem = itemQueue.take(); typeItemHander.get(eventItem.getEventType()).handle(eventItem); }}
针对不同消息的处理器接口:
public interface ItemHander<T> { void handle(EventItem<T> eventItem);}
本次的具体实现类, 本次放入消息的是货物:
@Data@AllArgsConstructorpublic class ConsumerItemHandler implements ItemHander<List<Good>> { private String name; @Override public void handle(EventItem<List<Good>> eventItem) { System.out.println(name + "收到了" + eventItem.getEventValue().toString()); }}
具体使用:
StopWatch stopwatch = StopWatch.createStarted();ItemQueue itemQueue = new ItemQueue();new ItemProducer(itemQueue).generateEvent(EventItemType.SEND_GOOD_TO_JIEKEMA, Arrays.asList(new Good("螃蟹"), new Good("河马")));new ItemProducer(itemQueue).generateEvent(EventItemType.SEND_GOOD_TO_NAICHA, Arrays.asList(new Good("奶茶")));new ItemProducer(itemQueue).generateEvent(EventItemType.SEND_GOOD_TO_XIAOMAGE, Arrays.asList(new Good("奶茶")));EnumMap<EventItemType, ItemHander> typeItemHander = new EnumMap<>(EventItemType.class);typeItemHander.put(EventItemType.SEND_GOOD_TO_JIEKEMA,new ConsumerItemHandler("杰克马"));typeItemHander.put(EventItemType.SEND_GOOD_TO_NAICHA,new ConsumerItemHandler("奶茶妹妹"));typeItemHander.put(EventItemType.SEND_GOOD_TO_XIAOMAGE,new ConsumerItemHandler("小马哥"));ItemConsumer itemConsumer = new ItemConsumer(itemQueue, typeItemHander);new Thread(() -> { while (true) { itemConsumer.handleEvent(); }}).start();Thread.sleep(1000);stopwatch.stop();System.out.println("total time: " + stopwatch.getTime(TimeUnit.SECONDS));
输出:
杰克马收到了[Good(name=螃蟹), Good(name=河马)]奶茶妹妹收到了[Good(name=奶茶)]小马哥收到了[Good(name=奶茶)]total time: 1
类图如下:
课后作业
-
把消息队列换成持久存储的方式
-
同时异步发送邮件和短信二种通知, 做一个邮件和短信的处理器
广告时间
最近也没人打赏了, 就我妈每次打赏二十元,,, 要放个广告了
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