多线程仅且只执行一次

Author: xhkyyy

java87/src/main/java/multi_threads/Test.java

@@ -0,0 +1,35 @@
+package multi_threads;
+
+import multi_threads.atomic_start_once.RWThread;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Test {
+    public static void main(String[] args) {
+
+        List<RWThread> list = new ArrayList<>();
+
+        for (int i = 0; i < 20; i++) {
+            list.add(new RWThread());
+        }
+
+        for (RWThread rwThread : list) {
+            rwThread.start();
+        }
+
+
+        for (RWThread rwThread : list) {
+            try {
+                rwThread.join();
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+
+        System.out.println();
+        System.out.println("count: " + RWThread.count);
+
+
+    }
+}

java87/src/main/java/multi_threads/atomic_start_once/RWThread.java

@@ -0,0 +1,23 @@
+package multi_threads.atomic_start_once;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class RWThread extends Thread {
+
+    public static final AtomicBoolean ab = new AtomicBoolean(false);
+
+    public static final AtomicInteger count = new AtomicInteger(0);
+
+
+    @Override
+    public void run() {
+
+        // 多线程环境下，保证仅且只执行一次
+        if (!ab.compareAndSet(false, true)) {
+            return;
+        }
+
+        count.incrementAndGet();
+    }
+}