步骤1：配置线程池，添加@Configuration和@EnableAsync注解

@Configuration@EnableAsyncpublic class ExecutorConfig {    /**   * 线程池   *   * @return   */  @Bean(name = "asyncExecutor")  public Executor asyncExecutor() {    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();    executor.setCorePoolSize(10);    executor.setMaxPoolSize(15);    executor.setQueueCapacity(25);    executor.setKeepAliveSeconds(200);    executor.setThreadNamePrefix("async-");    executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());    // 等待所有任务都完成再继续销毁其他的Bean    executor.setWaitForTasksToCompleteOnShutdown(true);    // 线程池中任务的等待时间，如果超过这个时候还没有销毁就强制销毁，以确保应用最后能够被关闭，而不是阻塞住    executor.setAwaitTerminationSeconds(60);    executor.initialize();    return executor;  }  }

步骤2：定义方法A，方法B，方法C，方法D

@Servicepublic class AsyncService {   @Async("asyncExecutor")  public Future methodB(){    try{      Thread.sleep(1000);    } catch (Exception e) {      e.printStackTrace();    }    return new AsyncResult<>(1);  }   @Async("asyncExecutor")  public Future methodC(){    try{      Thread.sleep(2000);    } catch (Exception e) {      e.printStackTrace();    }    return new AsyncResult<>(2);  }   @Async("asyncExecutor")  public Future methodD(){    try{      Thread.sleep(3000);    } catch (Exception e) {      e.printStackTrace();    }    return new AsyncResult<>(3);  }}@GetMapping("test")  public Integer methodA() throws Exception{    long start = System.currentTimeMillis();    Future future1 = asyncService.methodB();    Future future2 = asyncService.methodC();    Future future3 = asyncService.methodD();    Integer x = future1.get();    Integer y = future2.get();    Integer z = future3.get();    long end = System.currentTimeMillis();    System.out.println("耗时：" + (end - start));    return x + y +z;  }}