java：CompletableFuture的简单例子

package com.chz.myTest;import lombok.extern.slf4j.Slf4j;import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;@Slf4j
public class MyTestCompletableFutureTest
{public static void main1(String[] args) throws ExecutionException, InterruptedException{Future<String> completableFuture = CompletableFuture.completedFuture("Hello");String s = completableFuture.get();log.info(s);}public static void main2(String[] args) throws ExecutionException, InterruptedException{log.info("start");CompletableFuture<String> completableFuture = new CompletableFuture<>();new Thread(()->{try {Thread.sleep(2000);log.info("准备调用：complete()");completableFuture.complete("Hello");} catch (InterruptedException e) {throw new RuntimeException(e);}}).start();log.info("准备调用：completableFuture.get()");String s = completableFuture.get();     // 这里会被阻塞log.info("result: {}", s);}public static void main3(String[] args) throws ExecutionException, InterruptedException{log.info("start");CompletableFuture<String> completableFuture = new CompletableFuture<>();new Thread(()->{try {Thread.sleep(2000);log.info("准备调用：cancel()");completableFuture.cancel(true);} catch (InterruptedException e) {throw new RuntimeException(e);}}).start();log.info("准备调用：completableFuture.get()");try {String s = completableFuture.get();     // 这里会被阻塞log.info("result: {}", s);} catch (Exception e) {log.info("exception: {}, {}", e.getClass().getSimpleName(), e.getMessage(), e);}}public static void main4(String[] args) throws ExecutionException, InterruptedException{CompletableFuture<String> supplyAsync = CompletableFuture.supplyAsync(()->{return "supplyAsync";});String s = supplyAsync.get();log.info("result: " + s);}public static void main5(String[] args) throws ExecutionException, InterruptedException{CompletableFuture<String> stringCompletableFuture = CompletableFuture.supplyAsync(() -> "1");stringCompletableFuture = stringCompletableFuture.thenCompose(new Function<String, CompletionStage<String>>() {@Overridepublic CompletionStage<String> apply(String s) {log.info("s1: " + s);return CompletableFuture.supplyAsync(() -> s + " 2");}});stringCompletableFuture = stringCompletableFuture.thenCompose(new Function<String, CompletionStage<String>>() {@Overridepublic CompletionStage<String> apply(String s) {log.info("s2: " + s);return CompletableFuture.supplyAsync(() -> s + " 3");}});String s = stringCompletableFuture.get();log.info("s3: " + s);}public static void main6(String[] args) throws ExecutionException, InterruptedException{CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> "Hello").thenCombine(CompletableFuture.supplyAsync(() -> " World"),(s1, s2) -> s1 + s2);String s = completableFuture.get();log.info(s);}public static void main7(String[] args){CompletableFuture<Void> future = CompletableFuture.supplyAsync(() -> "Hello").thenAcceptBoth(CompletableFuture.supplyAsync(() -> " World"),(s1, s2) -> {log.info("result: " + (s1 + s2));});}public static void main8(String[] args) throws InterruptedException{CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> {log.info("1");return "Hello";});CompletableFuture<String> future2 = CompletableFuture.supplyAsync(() -> {log.info("2");return "Beautiful";});CompletableFuture<String> future3 = CompletableFuture.supplyAsync(() -> {log.info("3");return "World";});CompletableFuture<Void> voidCompletableFuture = CompletableFuture.allOf(future1, future2, future3);voidCompletableFuture.join();}public static void main9(String[] args){CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> "Hello");CompletableFuture<String> future2 = CompletableFuture.supplyAsync(() -> "Beautiful");CompletableFuture<String> future3 = CompletableFuture.supplyAsync(() -> "World");String combined = Stream.of(future1, future2, future3).map(CompletableFuture::join).collect(Collectors.joining(" "));log.info(combined);}public static void main10(String[] args) throws ExecutionException, InterruptedException{CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> {log.info("supplyAsync");throw new RuntimeException("Computation error!");});CompletableFuture<String> handle = completableFuture.handle((s, t) -> {log.info("handle");return (s != null) ? s : "Hello, Stranger!";});String s = handle.get();log.info("result: " + s);}}