CompletableFuture的使用

1、开启子线程并获取子线程结果

　　@Test
    public void test1() {
        SmallTool.printTimeAndThread("媳妇进入餐厅");
        SmallTool.printTimeAndThread("媳妇点饭， 蛋炒饭 + 米饭");
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            SmallTool.printTimeAndThread("厨师炒菜");
            SmallTool.sleepMillis(200);
            SmallTool.printTimeAndThread("厨师盛饭");
            SmallTool.sleepMillis(200);
            return "饭做好了";
        });
        SmallTool.printTimeAndThread("媳妇在玩手机");
        SmallTool.printTimeAndThread(String.format("%s, 媳妇开吃",future.join()));
    }

2、thenCompose:连接两个异步任务（第一个异步任务完成后执行第二个异步任务）

　　@Test
    public void test2() {
        SmallTool.printTimeAndThread("媳妇进入餐厅");
        SmallTool.printTimeAndThread("媳妇点饭， 蛋炒饭 + 米饭");
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            SmallTool.printTimeAndThread("厨师炒菜");
            SmallTool.sleepMillis(200);
            return "饭做好了";
        }).thenCompose(res -> CompletableFuture.supplyAsync(() -> { //厨师炒完菜服务员才端饭
            SmallTool.printTimeAndThread(res);
            SmallTool.printTimeAndThread("服务员端饭");
            SmallTool.sleepMillis(200);
            return "饭盛好了";
        }));
        SmallTool.printTimeAndThread("媳妇在玩手机");
        SmallTool.printTimeAndThread(String.format("%s, 媳妇开吃",future.join()));
    }

3、thenCombine:两个异步任务并行执行

　　@Test
    public void test3() {
        SmallTool.printTimeAndThread("媳妇进入餐厅");
        SmallTool.printTimeAndThread("媳妇点饭， 蛋炒饭 + 米饭");
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            SmallTool.printTimeAndThread("厨师炒菜");
            SmallTool.sleepMillis(200);
            return "菜做好了";
        }).thenCombine(CompletableFuture.supplyAsync(() -> { //炒菜和做饭同时进行
            SmallTool.sleepMillis(200);
            return "米饭做好了";
        }), (r1, r2) -> {
            SmallTool.printTimeAndThread("服务员端饭");
            SmallTool.sleepMillis(200);
            return String.format("%s和%s做好了", r1, r2);
        });
        SmallTool.printTimeAndThread("媳妇在玩手机");
        SmallTool.printTimeAndThread(String.format("%s, 媳妇开吃",future.join()));
    }

4、appltToEither:两个异步任务只有有一个执行完毕。exceptionally:异步任务中发送异常时执行

　　@Test
    public void test5() {
        SmallTool.printTimeAndThread("小白吃完饭打车");
        CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
            SmallTool.printTimeAndThread("700路公交车来了");
            SmallTool.sleepMillis(200);
            return "700路公交";
        }).applyToEither(CompletableFuture.supplyAsync(() -> {
            SmallTool.printTimeAndThread("800路公交车来了");
            SmallTool.sleepMillis(200);
            return "800路公交";
        }), firstComeBus -> {
            if(firstComeBus.startsWith("700")) {
                throw new RuntimeException("撞树上了");
            }
            return firstComeBus;
        }).exceptionally(e -> {
            SmallTool.printTimeAndThread("小白叫出租车");
            SmallTool.sleepMillis(200);
            return "出租车 叫到了";
        });
        SmallTool.printTimeAndThread(String.format("%s",future.join()));
    }

未完待续......