CompletableFuture implements asynchronous demo

Why use CompletableFuture?

 

solve. Waiting for the future at the place of future.get() is a synchronous operation. If you use the isDone() method for loop judgment, it is too time-consuming and laborious

public class Test {


    public static void main(String[] args) throws InterruptedException {

        MoneyServiceImpl MoneyServiceImpl=new MoneyServiceImpl();
        MoneyServiceImpl.addMoney(100).whenComplete((result,exc)->{
            if (exc == null) {
                System.out.println("结果为"+result);
            } else {
                System.out.println("发生异常"+exc);
            }
        });

        System.out.println("主线程执行结束");
        //这里是为了暂缓让主线程退出，让结果可以打印出来
        Thread.sleep(30000);

    }
}

The main thread calls the asynchronous method, and the whenComplete method of CompletableFuture is used to accept return or exception

 

Method implementation:

public class MoneyServiceImpl implements MoneyService {
    @Override
    public CompletableFuture<String> addMoney(int money) throws InterruptedException {
       return CompletableFuture.supplyAsync(()->{
            try {
                System.out.println("成功增加"+money);
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "第一步完成";
        }).thenApplyAsync(new Function<String, String>() {
           @Override
           public String apply(String lastResult) {
               //这里的入参是上一步的结果
               System.out.println(lastResult);
               return "扣减了"+money;
           }
       });
    }

    @Override
    public CompletableFuture<String> subMoney(int money) throws InterruptedException {
        return CompletableFuture.supplyAsync(()->{
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "成功扣减"+money;
        });
    }
}

in

The thenApplyAsync method passes the results of the previous thread to the next thread and continues asynchronous execution