异步方法测试（十）

测试

测试代码如下：

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@Component public class AppRunner implements CommandLineRunner {       private static final Logger logger = LoggerFactory.getLogger(AppRunner.class);       private final GitHubLookupService gitHubLookupService;       public AppRunner(GitHubLookupService gitHubLookupService) {         this.gitHubLookupService = gitHubLookupService;     }       @Override     public void run(String... args) throws Exception {         // Start the clock         long start = System.currentTimeMillis();           // Kick of multiple, asynchronous lookups         Future<User> page1 = gitHubLookupService.findUser("PivotalSoftware");         Future<User> page2 = gitHubLookupService.findUser("CloudFoundry");         Future<User> page3 = gitHubLookupService.findUser("Spring-Projects");           // Wait until they are all done         while (!(page1.isDone() && page2.isDone() && page3.isDone())) {             Thread.sleep(10); //10-millisecond pause between each check         }           // Print results, including elapsed time         logger.info("Elapsed time: " + (System.currentTimeMillis() - start));         logger.info("--> " + page1.get());         logger.info("--> " + page2.get());         logger.info("--> " + page3.get());     }   }

启动程序，控制台会打印：

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2017-04-30 13:11:10.351 INFO 1511 — [ GithubLookup-1] com.forezp.service.GitHubLookupService : Looking up PivotalSoftware 2017-04-30 13:11:10.351 INFO 1511 — [ GithubLookup-2] com.forezp.service.GitHubLookupService : Looking up CloudFoundry 2017-04-30 13:11:13.144 INFO 1511 — [ GithubLookup-2] com.forezp.service.GitHubLookupService : Looking up Spring-Projects

耗时：3908

分析：可以卡的前面2个方法分别在GithubLookup-1 和GithubLookup-2执行，第三个在GithubLookup-2执行，注意因为在配置线程池的时候最大线程为2.如果你把线程池的个数为3的时候，耗时减少。

如果去掉@Async，你会发现，执行这三个方法都在main线程中执行。耗时总结，如下：

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2017-04-30 13:13:00.934 INFO 1527 — [ main] com.forezp.service.GitHubLookupService : Looking up PivotalSoftware 2017-04-30 13:13:03.571 INFO 1527 — [ main] com.forezp.service.GitHubLookupService : Looking up CloudFoundry 2017-04-30 13:13:04.865 INFO 1527 — [ main] com.forezp.service.GitHubLookupService : Looking up Spring-Projects