https://www.cnblogs.com/qq931399960/p/15555152.html中的实现，无论是join还是futuretask都会阻塞主线程，影响效率
JDK8出现了一个新的类CompletableFuture，可以很容易的实现异步回调，使用该类实现订餐外卖
private static Logger logger = LoggerFactory.getLogger(OrderMealPlatformJDK8.class);
static Boolean merchantFinish = null;
static Boolean courierFinish = null;
public static void main(String[] args) {
try {
CompletableFuture.runAsync(() -> {
try {
logger.info("起锅烧油");
logger.info("炒菜");
// 5s炒菜时间
Thread.sleep(5000);
logger.info("盛饭");
logger.info("打包");
merchantFinish = true;
} catch (Exception e) {
logger.error("", e);
}
if (courierFinish != null) {
sendMeal(merchantFinish, courierFinish);
}
});
CompletableFuture.runAsync(() -> {
try {
logger.info("抢单");
logger.info("规划路线");
// 3s赶路时间
Thread.sleep(3000);
logger.info("赶路");
logger.info("到店");
courierFinish = true;
} catch (Exception e) {
logger.error("", e);
}
if (merchantFinish != null) {
sendMeal(merchantFinish, courierFinish);
}
});
} catch (Exception e) {
logger.error("", e);
}
logger.info("继续发布订单消息");
}
private static void sendMeal(boolean merchantResult, boolean courierResult) {
if (merchantResult && courierResult) {
logger.info("快递员开始送餐 。。。");
} else if (merchantResult && !courierResult) {
logger.error("外卖员车子被偷了，不能够送餐");
} else if (!merchantResult && courierResult) {
logger.error("商家厨师家里临时有事，请假了，做不了饭");
} else {
logger.error("外卖员车子被偷，商家厨师请假了 。。。 ");
}
}
View Code
运行结果如下：
18:24:38.425 [ForkJoinPool.commonPool-worker-1] INFO com.demo.order.OrderMealPlatformJDK8 - 起锅烧油 18:24:38.425 [main] INFO com.demo.order.OrderMealPlatformJDK8 - 继续发布订单消息 18:24:38.425 [ForkJoinPool.commonPool-worker-2] INFO com.demo.order.OrderMealPlatformJDK8 - 抢单 18:24:38.429 [ForkJoinPool.commonPool-worker-1] INFO com.demo.order.OrderMealPlatformJDK8 - 炒菜 18:24:38.429 [ForkJoinPool.commonPool-worker-2] INFO com.demo.order.OrderMealPlatformJDK8 - 规划路线View Code
可以发现，这个结果与我们期望的不一致，并且从线程名称可以看出，使用到了默认的ForkJoinPool线程池，该线程池的关闭不受我们控制，解决以上问题，可以使用自定义线程池来处理
private static Logger logger = LoggerFactory.getLogger(OrderMealPlatformJDK8.class);
static Boolean merchantFinish = null;
static Boolean courierFinish = null;
public static void main(String[] args) {
ThreadPoolExecutor pool = null;
try {
pool = new ThreadPoolExecutor(2, 2, 1000, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(4));
CompletableFuture.runAsync(() -> {
try {
logger.info("起锅烧油");
logger.info("炒菜");
// 5s炒菜时间
Thread.sleep(5000);
logger.info("盛饭");
logger.info("打包");
merchantFinish = true;
} catch (Exception e) {
logger.error("", e);
}
if (courierFinish != null) {
sendMeal(merchantFinish, courierFinish);
}
}, pool);
CompletableFuture.runAsync(() -> {
try {
logger.info("抢单");
logger.info("规划路线");
// 3s赶路时间
Thread.sleep(3000);
logger.info("赶路");
logger.info("到店");
courierFinish = true;
} catch (Exception e) {
logger.error("", e);
}
if (merchantFinish != null) {
sendMeal(merchantFinish, courierFinish);
}
}, pool);
} catch (Exception e) {
logger.error("", e);
} finally {
// 模拟真实使用线程池情况,如果直接在这里执行shutdownThreadPoolGracefully方法，则main方法会阻塞（原因还不清楚）
ThreadPoolRunnable tpr = new ThreadPoolRunnable(pool);
Thread closePool = new Thread(tpr);
closePool.start();
}
logger.info("继续发布订单消息");
}
private static void sendMeal(boolean merchantResult, boolean courierResult) {
if (merchantResult && courierResult) {
logger.info("快递员开始送餐 。。。");
} else if (merchantResult && !courierResult) {
logger.error("外卖员车子被偷了，不能够送餐");
} else if (!merchantResult && courierResult) {
logger.error("商家厨师家里临时有事，请假了，做不了饭");
} else {
logger.error("外卖员车子被偷，商家厨师请假了 。。。 ");
}
}
class ThreadPoolRunnable implements Runnable {
private Logger logger = LoggerFactory.getLogger(ThreadPoolRunnable.class);
private ExecutorService pool;
public ThreadPoolRunnable(ExecutorService pool) {
this.pool = pool;
}
@Override
public void run() {
// 如果在main方法的finally中执行该方法，则会出现main方法被阻塞（原因未知），此处模拟
shutdownThreadPoolGracefully(pool);
}
private void shutdownThreadPoolGracefully(ExecutorService pool) {
if (pool == null) {
return;
}
if (!(pool instanceof ExecutorService) || pool.isTerminated()) {
return;
}
try {
// 拒绝新任务的提交，并等待所有任务有序的执行完成
pool.shutdown();
} catch (Exception e) {
logger.error("", e);
}
try {
// 等待60s使线程池中的任务执行完
if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
// 将鲜橙汁状态设置为STOP，中断所有线程，清空工作队列，取出所有未完成的任务返回给调用者
pool.shutdownNow();
if (!pool.awaitTermination(60, TimeUnit.SECONDS)) {
// 再次尝试60s
logger.error("线程池未正常执行结束");
}
}
} catch (Exception e) {
pool.shutdownNow();
}
// 仍然未关闭
if (!pool.isTerminated()) {
try {
for (int i = 0; i < 1000; i++) {
if (pool.awaitTermination(10, TimeUnit.MILLISECONDS)) {
break;
}
pool.shutdownNow();
}
} catch (Exception e) {
logger.error("", e);
}
}
}
}