Semaphore

Author: ZHENFENG13

src/chapter3/SemapDemo.java

@@ -0,0 +1,38 @@
+package chapter3;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Semaphore;
+
+/**
+ * 信号量
+ * Created by 13 on 2017/5/5.
+ */
+public class SemapDemo implements Runnable {
+    final Semaphore semp = new Semaphore(5);
+
+    @Override
+    public void run() {
+        try {
+            semp.acquire();
+            Thread.sleep(2000);
+            System.out.println(Thread.currentThread().getId() + ":done!");
+            semp.release();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * 总共20个线程,系统会以5个线程一组为单位,依次执行并输出
+     *
+     * @param args
+     */
+    public static void main(String args[]) {
+        ExecutorService executorService = Executors.newFixedThreadPool(20);
+        final SemapDemo demo = new SemapDemo();
+        for (int i = 0; i < 20; i++) {
+            executorService.submit(demo);
+        }
+    }
+}