✨ 两个线程交替执行

crossoverJie · crossoverJie · commit 38a575110e7f · 2018-02-11T11:35:05.000+08:00
diff --git a/README.md b/README.md
@@ -14,7 +14,7 @@
 - [ConcurrentHashMap 的实现原理](https://github.com/crossoverJie/Java-Interview/blob/master/MD/ConcurrentHashMap.md)
 - [线程池原理](https://github.com/crossoverJie/Java-Interview/blob/master/MD/ThreadPoolExecutor.md)
 - [线程间通信](https://github.com/crossoverJie/Java-Interview/blob/master/src/main/java/com/crossoverjie/actual/ThreadCommunication.java)
-
+- 交替打印奇偶数
 
 ### Java 底层
 - [Java 运行时内存划分](https://github.com/crossoverJie/Java-Interview/blob/master/MD/MemoryAllocation.md)
diff --git a/src/main/java/com/crossoverjie/actual/TwoThread.java b/src/main/java/com/crossoverjie/actual/TwoThread.java
@@ -0,0 +1,115 @@
+package com.crossoverjie.actual;
+
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Function: 两个线程交替执行打印 1~100
+ *
+ * @author crossoverJie
+ *         Date: 11/02/2018 10:04
+ * @since JDK 1.8
+ */
+public class TwoThread {
+
+    private int start = 1 ;
+
+    /**
+     * 保证内存可见性
+     * 其实用锁了之后也可以保证可见性 这里用不用 volatile 都一样
+     */
+    private boolean flag = false ;
+
+    /**
+     * 重入锁
+     */
+    private final static Lock LOCK = new ReentrantLock() ;
+
+    public static void main(String[] args) {
+        TwoThread twoThread = new TwoThread() ;
+
+        Thread t1 = new Thread(new OuNum(twoThread));
+        t1.setName("t1");
+
+
+        Thread t2 = new Thread(new JiNum(twoThread)) ;
+        t2.setName("t2");
+
+        t1.start();
+        t2.start();
+    }
+
+    /**
+     * 偶数线程
+     */
+    public static class OuNum implements  Runnable{
+
+        private TwoThread number ;
+
+        public OuNum(TwoThread number) {
+            this.number = number;
+        }
+
+        @Override
+        public void run() {
+            while (number.start <= 100){
+
+                    if (number.flag){
+                        try {
+                            LOCK.lock();
+                            System.out.println(Thread.currentThread().getName() + "+-+" + number.start);
+                            number.start++;
+                            number.flag = false;
+
+
+                        }finally {
+                            LOCK.unlock();
+                        }
+                    }else {
+                        try {
+                            Thread.sleep(10);
+                        } catch (InterruptedException e) {
+                            e.printStackTrace();
+                        }
+                    }
+            }
+        }
+    }
+
+    /**
+     * 奇数线程
+     */
+    public static class JiNum implements  Runnable{
+
+        private TwoThread number ;
+
+        public JiNum(TwoThread number) {
+            this.number = number;
+        }
+
+        @Override
+        public void run() {
+            while (number.start <= 100){
+
+                    if (!number.flag){
+                        try {
+                        LOCK.lock();
+                        System.out.println( Thread.currentThread().getName() + "+-+" + number.start);
+                        number.start++;
+                        number.flag = true;
+
+
+                        }finally {
+                            LOCK.unlock();
+                        }
+                    }else {
+                        try {
+                            Thread.sleep(10);
+                        } catch (InterruptedException e) {
+                            e.printStackTrace();
+                        }
+                    }
+            }
+        }
+    }
+}
