Create CountDownLatchExample1.java

Author: Snailclimb

source-code/start/hello-world/src/main/java/com/example/helloworld/controller/CountDownLatchExample1.java

@@ -0,0 +1,44 @@
+package com.example.helloworld.controller;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * @author SnailClimb
+ * @date 2018年10月1日
+ * @Description: CountDownLatch 使用方法示例
+ */
+public class CountDownLatchExample1 {
+    // 请求的数量
+    private static final int threadCount = 550;
+
+    public static void main(String[] args) throws InterruptedException {
+        // 创建一个具有固定线程数量的线程池对象（如果这里线程池的线程数量给太少的话你会发现执行的很慢）
+        ExecutorService threadPool = Executors.newFixedThreadPool(300);
+        final CountDownLatch countDownLatch = new CountDownLatch(threadCount);
+        for (int i = 0; i < threadCount - 1; i++) {
+            final int threadnum = i;
+            threadPool.execute(() -> {// Lambda 表达式的运用
+                try {
+                    test(threadnum);
+                } catch (InterruptedException e) {
+                    // TODO Auto-generated catch block
+                    e.printStackTrace();
+                } finally {
+                    countDownLatch.countDown();// 表示一个请求已经被完成
+                }
+
+            });
+        }
+        countDownLatch.await();
+        threadPool.shutdown();
+        System.out.println("finish");
+    }
+
+    public static void test(int threadnum) throws InterruptedException {
+        Thread.sleep(1000);// 模拟请求的耗时操作
+        System.out.println("threadnum:" + threadnum);
+        Thread.sleep(1000);// 模拟请求的耗时操作
+    }
+}