学习参考文章：https://www.jianshu.com/p/6bac52527ca4(CompletableFuture 使用详解)
上代码：
package com.luck.util;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import java.util.concurrent.CompletableFuture;public class CompletableFutureUtil {
private static Logger logger = LoggerFactory.getLogger(CompletableFutureUtil.class);public static void main(String[] args) throws Exception{
//logger.info("有返回结果: " + CompletableFutureUtil.asyncString().get());//logger.info("没有返回结果: " + CompletableFutureUtil.asyncVoid().get());//logger.info("全部执行完毕返回: " + CompletableFutureUtil.asyncAll().get());//logger.info("任意执行完毕返回: " + CompletableFutureUtil.asyncAny().get());//logger.info("任务1执行完成后执行任务2(返回结果为任务1): " + CompletableFutureUtil.whenComplete().get());logger.info("任务1执行完成后执行任务2(返回结果为任务2): " + CompletableFutureUtil.thenApply().get());logger.info("任务1执行完成后执行任务2(返回结果为任务2): " + CompletableFutureUtil.thenCompose().get());//logger.info("任务1执行完成后执行任务2(返回结果为任务2) 可处理异常: " + CompletableFutureUtil.handle().get());//logger.info("任务1执行完成后执行任务2(无返回结果): " + CompletableFutureUtil.thenAccept().get());//logger.info("任务1执行完成后执行任务2(无返回结果)不关注任务1结果: " + CompletableFutureUtil.thenRun().get());//logger.info("合并任务，有结果：" + CompletableFutureUtil.thenCombine().get());//logger.info("合并任务结果，无结果：" + CompletableFutureUtil.thenAcceptBoth().get());//logger.info("任意执行完毕，进行下一步 - 接收结果 - 有返回结果：" + CompletableFutureUtil.applyToEither().get());//logger.info("任意执行完毕，进行下一步 - 接收结果 - 无返回结果：" + CompletableFutureUtil.acceptEither().get());//logger.info("任意执行完毕，进行下一步 - 不接收结果：" + CompletableFutureUtil.runAfterEither().get());//logger.info("都执行结束，进行下一步 - 不接收结果: " + CompletableFutureUtil.runAfterBoth().get());Thread.sleep(2000);}// 执行异步 -- 支持返回值private static CompletableFuture<String> asyncString(){
return CompletableFuture.supplyAsync(() -> CompletableFutureUtil.executeMethod("supplyAsync"));}// 执行异步 -- 不支持返回值private static CompletableFuture<Void> asyncVoid() {
return CompletableFuture.runAsync(() -> CompletableFutureUtil.executeMethod("runAsync"));}// 全部执行完毕返回private static CompletableFuture<Void> asyncAll() {
return CompletableFuture.allOf(asyncString(), asyncVoid());}// 任意一个执行完毕返回private static CompletableFuture<Object> asyncAny() {
return CompletableFuture.anyOf(asyncString(), asyncVoid());}// 任务1 执行完毕后 执行2 -- 不影响返回结果private static CompletableFuture<String> whenComplete() {
CompletableFuture<String> stringCompletableFuture = asyncString();CompletableFuture<String> stringCompletableFuture1 = stringCompletableFuture.whenComplete((a, b) -> {
a = "whenComplete处理返回结果";logger.info("任务 asyncString 执行完毕: 结果" + a);});CompletableFuture<String> exceptionally = stringCompletableFuture.exceptionally((a) -> {
logger.info("任务 asyncString 执行失败:" + a.getMessage());return null;});return stringCompletableFuture1;}// 任务1 执行完成后 执行2 -- 影响返回结果 -- 串行化private static CompletableFuture<String> thenApply() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenApply((a) -> {
logger.info("任务 asyncString 执行完毕: 结果" + a);return "thenApply处理返回结果" + a;});}// 任务1 执行完成后 执行2 -- 影响返回结果 -- 串行化private static CompletableFuture<String> thenCompose () {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenCompose(param -> CompletableFuture.supplyAsync(() -> {
logger.info("任务 asyncString 执行完毕: 结果" + param);return "thenApply处理返回结果" + param;}));}// 任务1 执行完成后 执行2 -- 影响返回结果 -- 可处理异常private static CompletableFuture<String> handle() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.handle((a, b) -> {
if (b != null) {
return "异常" + b.getMessage();}return "handle处理返回结果" + a;});}// 任务1 执行完成后 执行2 -- 无返回结果 -- 接收任务1的值private static CompletableFuture<Void> thenAccept() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenAccept((a) -> {
logger.info("任务 asyncString 执行完毕: 结果" + a);});}// 任务1 执行完成后 执行2 -- 无返回结果 -- 不接收任务1的值private static CompletableFuture<Void> thenRun() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenRun(() -> {
logger.info("任务 asyncString 执行完毕, 不关注结果." );});}// 合并任务 -- 并返回结果private static CompletableFuture<String> thenCombine() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenCombine(asyncVoid(), (a, b) -> {
logger.info("a:{}, b:{}", a, b);return "a+b:" + a + b;});}// 合并任务 -- 无返回结果private static CompletableFuture<Void> thenAcceptBoth() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.thenAcceptBoth(asyncString(), (a, b) -> {
logger.info("a:{}, b:{}", a, b);});}// 任意执行完毕，进行下一步 - 接收结果 - 有返回结果private static CompletableFuture<String> applyToEither() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.applyToEither(asyncString(), (a) -> {
logger.info("执行快的结果：{}", a);return "执行快的结果:" + a;});}// 任意执行完毕，进行下一步 - 接收结果 - 无返回结果private static CompletableFuture<Void> acceptEither() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.acceptEither(asyncString(), (a) -> {
logger.info("执行快的结果：{}", a);});}// 任意执行完毕，进行下一步 - 不接收结果private static CompletableFuture<Void> runAfterEither() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.runAfterEither(asyncString(), () -> {
logger.info("已经有任务执行结束");});}// 都执行结束，进行下一步 - 不接收结果private static CompletableFuture<Void> runAfterBoth() {
CompletableFuture<String> stringCompletableFuture = asyncString();return stringCompletableFuture.runAfterBoth(asyncString(), () -> {
logger.info("任务全部执行结束");});}private static String executeMethod(String param) {
try {
Thread.sleep(1000);} catch (InterruptedException e) {
e.printStackTrace();}//System.out.println("executeMethod -- > " + param);logger.info("executeMethod -- > " + param);return param;}
}