第四周作业2：使用completableFuture

chengfpvoid · chengfpvoid · commit 732a43f9d2d9 · 2020-11-11T22:02:41.000+08:00
diff --git a/03concurrency/0301/src/main/java/java0/conc0303/Homework03.java b/03concurrency/0301/src/main/java/java0/conc0303/Homework03.java
@@ -1,53 +1,51 @@
 package java0.conc0303;
 
+import java.util.concurrent.CompletableFuture;
+
 /**
  * 本周作业：（必做）思考有多少种方式，在main函数启动一个新线程或线程池，
  * 异步运行一个方法，拿到这个方法的返回值后，退出主线程？
  * 写出你的方法，越多越好，提交到github。
- *
+ * <p>
  * 一个简单的代码参考：
  */
 public class Homework03 {
-    
+
     public static void main(String[] args) throws Exception {
-        
-        long start=System.currentTimeMillis();
+
+        long start = System.currentTimeMillis();
         // 在这里创建一个线程或线程池，
         // 异步执行 下面方法
-       // CountDownLatch countDownLatch = new CountDownLatch(1);
-       // ExecutorService executorService = Executors.newCachedThreadPool();
-
-       // Future<Integer> future = executorService.submit(() -> sum());
-       // executorService.execute( () -> {
-       //    int result = sum();
-       //     System.out.println("异步计算结果为："+result);
-       //     countDownLatch.countDown();
-       // });
-       // executorService.shutdown();
-       // countDownLatch.await();
-       Thread t1 =  new Thread(() -> {
-            int result = sum();
-            System.out.println("异步计算结果为："+result);
-        });
-       t1.start();
-       t1.join();
+        // CountDownLatch countDownLatch = new CountDownLatch(1);
+        // ExecutorService executorService = Executors.newCachedThreadPool();
+
+        // Future<Integer> future = executorService.submit(() -> sum());
+        // executorService.execute( () -> {
+        //    int result = sum();
+        //     System.out.println("异步计算结果为："+result);
+        //     countDownLatch.countDown();
+        // });
+        // executorService.shutdown();
+        // countDownLatch.await();
+        int result = CompletableFuture.supplyAsync(()-> sum()).join();
+
         //int result = sum(); //这是得到的返回值
         //int result = future.get();
         // 确保  拿到result 并输出
-        //System.out.println("异步计算结果为："+result);
-         
-        System.out.println("使用时间："+ (System.currentTimeMillis()-start) + " ms");
-        
+        System.out.println("异步计算结果为："+result);
+
+        System.out.println("使用时间：" + (System.currentTimeMillis() - start) + " ms");
+
         // 然后退出main线程
     }
-    
+
     private static int sum() {
         return fibo(36);
     }
-    
+
     private static int fibo(int a) {
-        if ( a < 2) 
+        if (a < 2)
             return 1;
-        return fibo(a-1) + fibo(a-2);
+        return fibo(a - 1) + fibo(a - 2);
     }
 }
