在SpringBoot2中使用CompletableFuture的方法教程

@SpringBootApplication
@EnableAsync
public class App {
 RestTemplate
 public static void main(String[] args) {
  SpringApplication.run(App.class, args);
 }
}

// Source : https://spring.io/guides/gs/async-method/
package hello;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

import java.util.concurrent.CompletableFuture;

@Service
public class GitHubLookupService {

  private static final Logger logger = LoggerFactory.getLogger(GitHubLookupService.class);

  private final RestTemplate restTemplate;

  public GitHubLookupService(RestTemplateBuilder restTemplateBuilder) {
    this.restTemplate = restTemplateBuilder.build();
  }

  @Async
  public CompletableFuture findUser(String user) throws InterruptedException {
    logger.info("Looking up " + user);
    String url = String.format("https://api.github.com/users/%s", user);
    User results = restTemplate.getForObject(url, User.class);
    // Artificial delay of 1s for demonstration purposes
    Thread.sleep(1000L);
    return CompletableFuture.completedFuture(results);
  }

}

return CompletableFuture.completedFuture(results);

@Async
  public CompletableFuture isServerAlive(String ip) {
    CompletableFuture future = new CompletableFuture(){
      @Override
      public Boolean get() throws InterruptedException, ExecutionException {
        InetAddress address = null;
        try {
          address = InetAddress.getByName(ip);
          return address.isReachable(1000);
        } catch (UnknownHostException e) {
          e.printStackTrace();
          return false;
        } catch (IOException e) {
          e.printStackTrace();
          return false;
        }
      }
    };
    return future;
}