对计算速度进行选用

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;public class Test4 {public static void main(String[] args) {CompletableFuture<String> a = CompletableFuture.supplyAsync(() -> {try { TimeUnit.SECONDS.sleep(4); } catch (InterruptedException e) {e.printStackTrace();}return "a";});CompletableFuture<String> b = CompletableFuture.supplyAsync(() -> {try { TimeUnit.SECONDS.sleep(3); } catch (InterruptedException e) {e.printStackTrace();}return "b";});//谁快用谁CompletableFuture<String> result = a.applyToEither(b, f -> {return f;});System.out.println(result.join());}
}

对计算结果进行合并

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;public class Test4 {public static void main(String[] args) {CompletableFuture<Integer> a = CompletableFuture.supplyAsync(() -> {try { TimeUnit.SECONDS.sleep(4); } catch (InterruptedException e) {e.printStackTrace();}return 10;});CompletableFuture<Integer> b = CompletableFuture.supplyAsync(() -> {try { TimeUnit.SECONDS.sleep(3); } catch (InterruptedException e) {e.printStackTrace();}return 20;});//等待俩者结果一起返回CompletableFuture<Integer> result = a.thenCombine(b, (x,y) -> {return x + y;});System.out.println(result.join());}
}