{"id":10008250,"date":"2023-09-08T09:39:02","date_gmt":"2023-09-08T01:39:02","guid":{"rendered":"https:\/\/blog.itmax.cn\/?p=10008250"},"modified":"2023-09-08T09:39:02","modified_gmt":"2023-09-08T01:39:02","slug":"13%e5%88%86%e9%92%9f%e8%81%8a%e8%81%8a%e5%b9%b6%e5%8f%91%e5%8c%85%e4%b8%ad%e5%b8%b8%e7%94%a8%e5%90%8c%e6%ad%a5%e7%bb%84%e4%bb%b6%e5%b9%b6%e6%89%8b%e5%86%99%e4%b8%80%e4%b8%aa%e8%87%aa%e5%ae%9a%e4%b9%89","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008250","title":{"rendered":"13\u5206\u949f\u804a\u804a\u5e76\u53d1\u5305\u4e2d\u5e38\u7528\u540c\u6b65\u7ec4\u4ef6\u5e76\u624b\u5199\u4e00\u4e2a\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6"},"content":{"rendered":"

\u524d\u8a00<\/h3>\n

\u4e0a\u7bc7\u6587\u7ae010\u5206\u949f\u4ece\u6e90\u7801\u7ea7\u522b\u641e\u61c2AQS\uff08AbstractQueuedSynchronizer\uff09<\/a>\u8bf4\u5230JUC\u5e76\u53d1\u5305\u4e2d\u7684\u540c\u6b65\u7ec4\u4ef6\u5927\u591a\u4f7f\u7528AQS\u6765\u5b9e\u73b0<\/p>\n

\u672c\u7bc7\u6587\u7ae0\u901a\u8fc7AQS\u81ea\u5df1\u6765\u5b9e\u73b0\u4e00\u4e2a\u540c\u6b65\u7ec4\u4ef6\uff0c\u5e76\u4ece\u6e90\u7801\u7ea7\u522b\u804a\u804aJUC\u5e76\u53d1\u5305\u4e2d\u7684\u5e38\u7528\u540c\u6b65\u7ec4\u4ef6<\/p>\n

\u672c\u7bc7\u6587\u7ae0\u9700\u8981\u7684\u524d\u7f6e\u77e5\u8bc6\u5c31\u662fAQS\uff0c\u5982\u679c\u4e0d\u4e86\u89e3AQS\u7684\u540c\u5b66\u53ef\u4ee5\u770b\u4e0a\u4e00\u7bc7\u6587\u7ae0\u54c8~<\/p>\n

\u9605\u8bfb\u672c\u7bc7\u6587\u7ae0\u5927\u6982\u9700\u898113\u5206\u949f<\/p>\n

\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6<\/h3>\n

\u4e3a\u4e86\u66f4\u5bb9\u6613\u7406\u89e3\u5176\u4ed6\u540c\u6b65\u7ec4\u4ef6\uff0c\u6211\u4eec\u5148\u6765\u4f7f\u7528AQS\u81ea\u5df1\u6765\u5b9e\u73b0\u4e00\u4e2a\u5e38\u7528\u7684\u53ef\u91cd\u5165\u9501<\/p>\n

AQS\u6a21\u677f\u65b9\u6cd5\u6d41\u7a0b\u662f\u56fa\u5b9a\u7684\uff0c\u6211\u4eec\u4e3b\u8981\u53ea\u9700\u8981\u6765\u5b9e\u73b0\u5b83\u7684\u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u548c\u5c1d\u8bd5\u91ca\u653e\u540c\u6b65\u72b6\u6001\u65b9\u6cd5\u5373\u53ef<\/p>\n

\u9996\u5148\u6211\u4eec\u5148\u89c4\u5b9a\u8981\u5b9e\u73b0\u7684\u53ef\u91cd\u5165\u9501\u662f\u72ec\u5360\u5f0f\u7684<\/p>\n

\u89c4\u5b9a\u540c\u6b65\u72b6\u6001\u4e00\u5f00\u59cb\u4e3a0\uff0c\u5f53\u6709\u7ebf\u7a0b\u83b7\u53d6\u9501\u6210\u529f\u540c\u6b65\u72b6\u6001\u5c31\u4e3a1\uff0c\u5f53\u8fd9\u4e2a\u7ebf\u7a0b\u91cd\u5165\u65f6\u5c31\u7d2f\u52a0\u540c\u6b65\u72b6\u6001<\/p>\n

\u89c4\u5b9a\u91ca\u653e\u540c\u6b65\u72b6\u6001\u65f6\u6bcf\u6b21\u6263\u51cf1\u4e2a\u540c\u6b65\u72b6\u6001\uff0c\u53ea\u6709\u5f53\u540c\u6b65\u72b6\u6001\u6263\u51cf\u52300\u65f6\uff0c\u624d\u662f\u771f\u6b63\u7684\u91ca\u653e\u72ec\u5360\u9501<\/p>\n

\u6211\u4eec\u4f7f\u7528\u4e00\u4e2a\u5185\u90e8\u7c7bSync \u6765\u7ee7\u627fAQS \u5e76\u91cd\u5199tryAcquire<\/code>\u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u3001tryRelease<\/code> \u5c1d\u8bd5\u91ca\u653e\u540c\u6b65\u72b6\u6001\u3001isHeldExclusively<\/code>\u5224\u65ad\u5f53\u524d\u7ebf\u7a0b\u662f\u5426\u6301\u6709\u540c\u6b65\u72b6\u6001\uff08\u7b49\u5f85\u3001\u901a\u77e5\u65f6\u4f1a\u7528\u5230\u8be5\u65b9\u6cd5\uff09<\/p>\n

    static class Sync extends AbstractQueuedSynchronizer {\n        \/**\n         * \u5224\u65ad\u5f53\u524d\u7ebf\u7a0b\u662f\u5426\u6301\u6709\u540c\u6b65\u72b6\u6001\n         *\n         * @return\n         *\/\n        @Override\n        protected boolean isHeldExclusively() {\n            return getExclusiveOwnerThread() == Thread.currentThread();\n        }\n    }<\/code><\/pre>\n
\u5728\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u4e2d<\/p>\n
    \n
  1. \u5148\u5224\u65ad\u662f\u5426\u6709\u540c\u6b65\u72b6\u6001\uff08\u5373\u540c\u6b65\u72b6\u6001\u662f\u5426\u4e3a0\uff09\uff0c\u5982\u679c\u6709\u540c\u6b65\u72b6\u6001\u5c31\u7528CAS\u53bb\u83b7\u53d6\uff080->1\uff09\uff0c\u6210\u529f\u5c31\u8bbe\u7f6e\u5f53\u524d\u7ebf\u7a0b\u4e3a\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u7684\u7ebf\u7a0b<\/strong><\/li>\n
  2. \u5982\u679c\u6ca1\u6709\u540c\u6b65\u72b6\u6001\uff08\u5373\u540c\u6b65\u72b6\u6001\u4e0d\u4e3a0\uff09 \uff0c\u5c31\u67e5\u770b\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u7684\u7ebf\u7a0b\u662f\u5426\u4e3a\u5f53\u524d\u7ebf\u7a0b\uff0c\u5982\u679c\u662f\u5f53\u524d\u7ebf\u7a0b\u5219\u8bf4\u660e\u6b64\u6b21\u662f\u91cd\u5165\uff0c\u7d2f\u52a0\u91cd\u5165\u6b21\u6570<\/strong><\/li>\n
  3. \u5176\u4ed6\u60c5\u51b5\u8bf4\u660e\u672a\u83b7\u53d6\u5230\u540c\u6b65\u72b6\u6001\uff0c\u8fd4\u56defalse  \u540e\u7eed\u8d70AQS\u6d41\u7a0b\uff08\u6784\u5efa\u8282\u70b9\u52a0\u5165AQS\uff09<\/strong><\/li>\n<\/ol>\n
            \/**\n         * \u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001\n         *\n         * @param arg \u83b7\u53d6\u540c\u6b65\u72b6\u6001\u7684\u6570\u91cf\n         * @return\n         *\/\n        @Override\n        protected boolean tryAcquire(int arg) {\n            \/\/1.\u83b7\u53d6\u540c\u6b65\u72b6\u6001\n            int state = getState();\n            \/\/2.\u5982\u679c\u6709\u540c\u6b65\u72b6\u6001\u5219CAS\u66ff\u6362 0->1\n            if (state == 0) {\n                if (compareAndSetState(state, 1)) {\n                    \/\/\u66ff\u6362\u6210\u529f \u8bf4\u660e\u83b7\u53d6\u5230\u540c\u6b65\u72b6\u6001 \u8bbe\u7f6e\u5f53\u524d\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u7ebf\u7a0b\n                    setExclusiveOwnerThread(Thread.currentThread());\n                    return true;\n                }\n            } else if (getExclusiveOwnerThread() == Thread.currentThread()) {\n                \/\/3.\u6ca1\u6709\u540c\u6b65\u72b6\u6001  \u67e5\u770b\u83b7\u53d6\u540c\u6b65\u8d44\u6e90\u7684\u7ebf\u7a0b\u662f\u5426\u4e3a\u5f53\u524d\u7ebf\u7a0b  \u53ef\u91cd\u5165  \u7d2f\u52a0\u91cd\u5165\u6b21\u6570\n                setState(state + arg);\n                return true;\n            }\n\n            \/\/\u5176\u4ed6\u60c5\u51b5\u5c31\u662f\u6ca1\u83b7\u53d6\u5230\u540c\u6b65\u72b6\u6001\n            return false;\n        }<\/code><\/pre>\n
    \u5728\u91ca\u653e\u540c\u6b65\u72b6\u6001\u4e2d<\/p>\n
    \u53ea\u6709\u5f53\u540c\u6b65\u72b6\u6001\u8981\u6539\u62100\u65f6\u624d\u662f\u771f\u6b63\u91ca\u653e\uff0c\u5426\u5219\u60c5\u51b5\u60c5\u51b5\u4e0b\u5c31\u662f\u91cd\u5165\u6263\u51cf\u6b21\u6570<\/strong><\/p>\n
            \/**\n         * \u5c1d\u8bd5\u91ca\u653e\u540c\u6b65\u72b6\u6001\n         *\n         * @param arg \u91ca\u653e\u540c\u6b65\u72b6\u6001\u7684\u6570\u91cf\n         * @return\n         *\/\n        @Override\n        protected boolean tryRelease(int arg) {\n            \/\/\u76ee\u6807\u72b6\u6001\n            int targetState = getState() - arg;\n\n            \/\/\u771f\u6b63\u91ca\u653e\u9501\n            if (targetState == 0) {\n                setExclusiveOwnerThread(null);\n                setState(targetState);\n                return true;\n            }\n\n            \/\/\u5176\u4ed6\u60c5\u51b5 \u6263\u51cf\u72b6\u6001\n            setState(targetState);\n            return false;\n        }<\/code><\/pre>\n
    \u4f7f\u7528\u5185\u90e8\u7c7b\u5b9e\u73b0AQS\u7684\u65b9\u6cd5\u540e\uff0c\u6211\u4eec\u5728\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6\u7c7b\u4e2d\u53bb\u5b9e\u73b0Lock\u63a5\u53e3\uff0c\u5e76\u7528\u5185\u90e8\u7c7b\u5b9e\u73b0AQS\u7684\u65b9\u6cd5\u53bb\u5b9e\u73b0Lock\u63a5\u53e3\u7684\u65b9\u6cd5<\/p>\n
    \u5c06\u8981\u83b7\u53d6\u3001\u91ca\u653e\u7684\u540c\u6b65\u72b6\u6001\u90fd\u8bbe\u7f6e\u62101\uff0c\u5bf9\u5e94\u54cd\u5e94\u4e2d\u65ad\u3001\u8d85\u65f6\u7684\u65b9\u6cd5\u5c31\u7528AQS\u4e2d\u5bf9\u5e94\u7684\u65b9\u6cd5\u5373\u53ef<\/p>\n
    public class MySynchronizedComponent implements Lock {\n\n    public MySynchronizedComponent() {\n        sync = new Sync();\n    }\n\n    private Sync sync;\n\n    @Override\n    public void lock() {\n        sync.acquire(1);\n    }\n\n    @Override\n    public void lockInterruptibly() throws InterruptedException {\n        sync.acquireInterruptibly(1);\n    }\n\n    @Override\n    public boolean tryLock() {\n        return sync.tryAcquire(1);\n    }\n\n    @Override\n    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {\n        return sync.tryAcquireNanos(1, unit.toNanos(time));\n    }\n\n    @Override\n    public void unlock() {\n        sync.release(1);\n    }\n\n    @Override\n    public Condition newCondition() {\n        return sync.new ConditionObject();\n    }\n\n}<\/code><\/pre>\n
    \u5b9e\u9645\u4e0a\u6211\u4eec\u53ea\u9700\u8981\u53bb\u5b9e\u73b0\u5c1d\u8bd5\u83b7\u53d6\u3001\u91ca\u653e\u540c\u6b65\u72b6\u6001\u65b9\u6cd5\u5c31\u80fd\u591f\u5b8c\u6210\u81ea\u5df1\u7684\u540c\u6b65\u7ec4\u4ef6\uff0c\u8fd9\u5c31\u662f\u4f7f\u7528AQS\u5e26\u6765\u7684\u597d\u5904<\/p>\n
    \u4ee3\u7801\u6848\u4f8b\u53ef\u4ee5\u53bbgit\u4ed3\u5e93\u83b7\u53d6\uff0c\u653e\u5728\u672c\u6587\u6700\u540e<\/p>\n
    ReentrantLock<\/h3>\n
    ReentrantLock\u662f\u5e76\u53d1\u5305\u4e2d\u63d0\u4f9b\u7684\u53ef\u91cd\u5165\u9501\uff0c\u5b83\u9664\u4e86\u80fd\u591f\u5b9e\u73b0synchronized\u7684\u529f\u80fd\u5916\u8fd8\u53ef\u4ee5\u54cd\u5e94\u4e2d\u65ad\u3001\u8d85\u65f6\u3001\u5b9e\u73b0\u516c\u5e73\u9501\u7b49\uff0c\u5176\u5e95\u5c42\u4e5f\u662f\u901a\u8fc7AQS\u6765\u5b9e\u73b0\u7684<\/p>\n
    ReentrantLock\u7684\u529f\u80fd\u4e0esynchronized\u7c7b\u4f3c\uff0c\u53ef\u91cd\u5165\u7684\u72ec\u5360\u9501\uff0c\u7528\u4e8e\u4fdd\u8bc1\u5e76\u53d1\u573a\u666f\u4e0b\u540c\u6b65\u64cd\u4f5c<\/p>\n
    \u4f7f\u7528\u65f6\u9700\u8981\u663e\u793a\u52a0\u9501\u3001\u89e3\u9501\uff0c\u5e38\u7528\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n
    reentrantLock.lock();\ntry{\n    \/\/....\n}finally {\n    reentrantLock.unlock();\n}<\/code><\/pre>\n
    finally\u4e2d\u6700\u5148\u53bb\u89e3\u9501\uff0c\u5e76\u4e14\u52a0\u9501\u8981\u653e\u5728try\u5757\u7684\u6700\u5916\u5c42\uff0c\u5e76\u4fdd\u8bc1\u52a0\u9501\u548ctry\u5757\u4e4b\u95f4\u4e0d\u4f1a\u629b\u51fa\u5f02\u5e38<\/strong><\/p>\n
    \u52a0\u9501\u4e0d\u653e\u5728try\u4e2d\u662f\u56e0\u4e3a\u52a0\u9501\u5b9e\u73b0\u672a\u77e5\u53ef\u80fd\u629b\u51fa\u4e0d\u53d7\u68c0\u67e5unchecked\u7684\u5f02\u5e38\uff0c\u5f53\u52a0\u9501\u629b\u51fa\u5f02\u5e38\u65f6\uff0c\u540e\u7eedfinally\u5757\u89e3\u9501\u4e5f\u4f1a\u629b\u51fa\u975e\u6cd5\u76d1\u89c6\u5668\u7684\u5f02\u5e38\u4ece\u800c\u5bfc\u81f4\u8986\u76d6<\/strong><\/p>\n
    \u52a0\u9501\u548ctry\u5757\u4e4b\u95f4\u5982\u679c\u629b\u51fa\u5f02\u5e38\uff0c\u90a3\u4e48\u5c31\u65e0\u6cd5\u6267\u884c\u89e3\u9501\u4e86<\/strong><\/p>\n
    ReentrantLock\u9664\u4e86\u63d0\u4f9b\u57fa\u672c\u7684\u540c\u6b65\u529f\u80fd\uff0c\u8fd8\u63d0\u4f9b\u54cd\u5e94\u4e2d\u65ad\u3001\u8d85\u65f6\u7684API\uff0c\u540c\u5b66\u4eec\u53ef\u4ee5\u79c1\u4e0b\u53bb\u67e5\u770b<\/p>\n
    \u719f\u6089ReentrantLock\u5b9e\u73b0\u7684\u540c\u5b66\uff0c\u53ef\u80fd\u770b\u4e0a\u9762\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6\u7684\u4ee3\u7801\u5f88\u719f\u6089\uff0c\u5176\u5b9e\u5c31\u662f\u53c2\u8003ReentrantLock\u975e\u516c\u5e73\u9501\u5199\u7684<\/p>\n
    ReentrantLock\u4e2d\u4f7f\u7528\u5185\u90e8\u7c7bSync\u6765\u7ee7\u627fAQS\uff0c\u540c\u65f6\u5185\u90e8\u7c7bNonfairSync\u548cFairSync\u6765\u7ee7\u627fSync\u53bb\u5b9e\u73b0\u975e\u516c\u5e73\u3001\u516c\u5e73\u7684\u83b7\u53d6\u540c\u6b65\u72b6\u6001<\/strong><\/p>\n
    \"image.png\"<\/p>\n
    \u975e\u516c\u5e73\u9501\u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001 \u6d41\u7a0b\u7c7b\u4f3c\u5c31\u4e0d\u8fc7\u591a\u63cf\u8ff0<\/p>\n
            final boolean nonfairTryAcquire(int acquires) {\n            final Thread current = Thread.currentThread();\n            int c = getState();\n            if (c == 0) {\n                if (compareAndSetState(0, acquires)) {\n                    setExclusiveOwnerThread(current);\n                    return true;\n                }\n            }\n            else if (current == getExclusiveOwnerThread()) {\n                int nextc = c + acquires;\n                if (nextc < 0) \/\/ overflow\n                    throw new Error("Maximum lock count exceeded");\n                setState(nextc);\n                return true;\n            }\n            return false;\n        }<\/code><\/pre>\n
    \u90a3\u516c\u5e73\u9501\u5982\u4f55\u6765\u5b9e\u73b0\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u5462\uff1f<\/p>\n
    \u5176\u5b9e\u770b\u8fc7\u4e0a\u7bc7AQS\u6587\u7ae0\u7684\u540c\u5b66\u5c31\u77e5\u9053\u4e86\uff0c\u5728\u4e0a\u7bc7\u6587\u7ae0\u4e2d\u5df2\u7ecf\u8bf4\u8fc7<\/p>\n
    \u53ea\u9700\u8981\u5728\u5c1d\u8bd5\u83b7\u53d6\u540c\u6b65\u72b6\u6001\u524d\u52a0\u4e0a\u4e00\u4e2a\u6761\u4ef6\uff1a\u961f\u5217\u4e2d\u662f\u5426\u6709\u524d\u7f6e\u4efb\u52a1\uff08\u5373\u5728\u961f\u5217\u4e2dFIFO\u6392\u961f\u83b7\u53d6\uff09<\/p>\n
    \u516c\u5e73\u9501\u4e5f\u662f\u8fd9\u4e48\u53bb\u5b9e\u73b0\u7684\uff0c\u524d\u7f6e\u6761\u4ef6hasQueuedPredecessors<\/code><\/p>\n
            protected final boolean tryAcquire(int acquires) {\n            final Thread current = Thread.currentThread();\n            int c = getState();\n            if (c == 0) {\n                if (!hasQueuedPredecessors() &&\n                    compareAndSetState(0, acquires)) {\n                    setExclusiveOwnerThread(current);\n                    return true;\n                }\n            }\n            else if (current == getExclusiveOwnerThread()) {\n                int nextc = c + acquires;\n                if (nextc < 0)\n                    throw new Error("Maximum lock count exceeded");\n                setState(nextc);\n                return true;\n            }\n            return false;\n        }<\/code><\/pre>\n
    ReentrantReadWriteLock<\/h3>\n
    \u529f\u80fd\u4e0e\u5b9e\u73b0<\/h4>\n
    ReentrantReadWriteLock\u5728ReentrantLock\u529f\u80fd\u7684\u57fa\u7840\u4e0a\uff0c\u63d0\u4f9b\u8bfb\u5199\u9501\u7684\u529f\u80fd\uff0c\u8ba9\u9501\u7684\u7c92\u5ea6\u66f4\u7ec6<\/p>\n
    \u5728\u4e00\u4e9b\u8bfb\u591a\u5199\u5c11\u7684\u573a\u666f\u4e0b\u662f\u5141\u8bb8\u540c\u65f6\u8bfb\u7684\uff0c\u5141\u8bb8\u591a\u4e2a\u7ebf\u7a0b\u83b7\u53d6\uff0c\u5176\u5b9e\u60f3\u5230\u4e86AQS\u7684\u5171\u4eab\u5f0f\uff0c\u8bfb\u9501\u4e5f\u5c31\u662f\u5171\u4eab\u5f0f<\/p>\n
    \u5728\u8bfb\u8bfb\u7684\u573a\u666f\u4e0b\uff0c\u90fd\u662f\u8bfb\u9501\/\u5171\u4eab\u9501\uff0c\u4e0d\u4f1a\u8fdb\u884c\u963b\u585e<\/strong><\/p>\n
    \u5728\u8bfb\u5199\u3001\u5199\u8bfb\u3001\u5199\u5199\u7684\u573a\u666f\u4e0b\uff0c\u90fd\u4f1a\u8fdb\u884c\u963b\u585e<\/strong><\/p>\n
    \u6bd4\u5982\u8981\u83b7\u53d6\u5199\u9501\u65f6\uff0c\u9700\u8981\u7b49\u5f85\u8bfb\u9501\u3001\u5199\u9501\u90fd\u89e3\u9501\uff1b\u8981\u83b7\u53d6\u8bfb\u9501\u65f6\uff0c\u9700\u8981\u7b49\u5f85\u5199\u9501\u89e3\u9501<\/p>\n
    ReentrantReadWriteLock \u5728 ReentrantLock \u7684\u57fa\u7840\u4e0a\u589e\u52a0ReadLock<\/code>\u548cWriteLock<\/code>\u5206\u522b\u4f5c\u4e3a\u8bfb\u9501\u548c\u5199\u9501<\/p>\n
    \"image.png\"<\/p>\n
    \u5b9e\u9645\u4e0a\u8bfb\u9501\u5c31\u662f\u5171\u4eab\u9501\u3001\u5199\u9501\u5c31\u662f\u72ec\u5360\u9501\uff0c\u5728\u5b9e\u73b0\u52a0\u9501\u3001\u89e3\u9501\u7684\u65b9\u6cd5\u65f6\u5206\u522b\u8c03\u7528\u5171\u4eab\u5f0f\u3001\u72ec\u5360\u5f0f\u7684\u83b7\u53d6\u3001\u91ca\u653e\u540c\u6b65\u72b6\u6001\u5373\u53ef<\/p>\n
    \u5728\u6784\u9020\u65f6\uff0c\u8bfb\u5199\u9501\u4e2d\u5b9e\u9645\u4f7f\u7528\u7684\u90fd\u662f\u540c\u4e00\u4e2aAQS<\/p>\n
            public ReentrantReadWriteLock(boolean fair) {\n            sync = fair ? new FairSync() : new NonfairSync();\n            readerLock = new ReadLock(this);\n            writerLock = new WriteLock(this);\n        }\n\n        \/\/\u8bfb\u9501\u6784\u9020\n        protected ReadLock(ReentrantReadWriteLock lock) {\n            sync = lock.sync;\n        }\n\n        \/\/\u5199\u9501\u6784\u9020\n        protected WriteLock(ReentrantReadWriteLock lock) {\n            sync = lock.sync;\n        }<\/code><\/pre>\n
    \u5373\u540c\u6b65\u72b6\u6001\u4f1a\u88ab\u8bfb\u5199\u9501\u5171\u4eab\uff0c\u90a3\u4e48\u5b83\u4eec\u5982\u4f55\u67e5\u770b\/\u4fee\u6539\u81ea\u5df1\u7684\u90a3\u90e8\u5206\u540c\u6b65\u72b6\u6001\u5462\uff1f<\/p>\n
    \u5728\u8bfb\u5199\u9501\u4e2d\uff0c\u540c\u6b65\u72b6\u6001\u88ab\u4e00\u5206\u4e3a\u4e8c\uff0c\u9ad816\u4f4d\u7684\u540c\u6b65\u72b6\u6001\u662f\u8bfb\u9501\u7684\uff0c\u4f4e16\u4f4d\u7684\u540c\u6b65\u72b6\u6001\u662f\u5199\u9501\u7684<\/strong><\/p>\n
    \"image.png\"<\/p>\n
    \u5f53\u7ebf\u7a0b\u83b7\u53d6\u5199\u9501\u65f6\uff0c\u5199\u72b6\u6001+1\uff0c\u7531\u4e8e\u5199\u72b6\u6001\u5728\u4f4e\u4f4d\uff0c\u76f8\u5f53\u4e8e\u540c\u6b65\u72b6\u6001+1<\/strong><\/p>\n
    \u5f53\u7ebf\u7a0b\u83b7\u53d6\u8bfb\u9501\u65f6\uff0c\u8bfb\u72b6\u6001+1\uff0c\u7531\u4e8e\u8bfb\u72b6\u6001\u5728\u9ad8\u4f4d\uff0c\u76f8\u5f53\u4e8e\u540c\u6b65\u72b6\u6001+\uff081<<16\uff09<\/strong><\/p>\n
    \u5199\u9501\u83b7\u53d6<\/h4>\n
    \u5199\u9501\u7684\u83b7\u53d6\u5b9e\u73b0\u5728sync.tryAcquire<\/code>\u4e2d sync\u53ef\u4ee5\u662f\u516c\u5e73\u4e5f\u53ef\u4ee5\u662f\u975e\u516c\u5e73\uff0c\u5b9e\u9645\u4e0a\u662f\u72ec\u5360\u5f0f\u7684\u83b7\u53d6<\/p>\n
    protected final boolean tryAcquire(int acquires) {\n  \n    Thread current = Thread.currentThread();\n    \/\/\u5f97\u5230\u540c\u6b65\u72b6\u6001c\n    int c = getState();\n    \/\/\u5f97\u5230\u5199\u72b6\u6001\uff08\u540c\u6b65\u72b6\u6001\u4f4e16\u4f4d \u4e0e\u4e0a \u51681\uff09\n    int w = exclusiveCount(c);\n    if (c != 0) {\n        \/\/\u540c\u6b65\u72b6\u6001\u4e0d\u4e3a0,\u5199\u72b6\u6001\u4e3a0,\u8bf4\u660e\u8bfb\u72b6\u6001\u4e0d\u4e3a0,\u8bfb\u9501\u5df2\u7ecf\u88ab\u83b7\u53d6,\u6b64\u65f6\u83b7\u53d6\u5199\u9501\u5931\u8d25\n        \/\/\u540c\u6b65\u72b6\u6001\u4e0d\u4e3a0,\u5199\u72b6\u6001\u4e5f\u4e0d\u4e3a0,\u67e5\u770b\u5f53\u524d\u7ebf\u7a0b\u662f\u5426\u662f\u83b7\u53d6\u5199\u9501\u7684\u7ebf\u7a0b,\u4e0d\u662f\u7684\u8bdd\u83b7\u53d6\u5199\u9501\u5931\u8d25\n        if (w == 0 || current != getExclusiveOwnerThread())\n            return false;\n        \n        \/\/\u53ea\u6709\u5f53\u524d\u7ebf\u7a0b\u83b7\u53d6\u8fc7\u5199\u9501\u624d\u80fd\u8fdb\u5165\u8fd9\u91cc\n        \n        \/\/\u5982\u679c\u539f\u6765\u7684\u5199\u72b6\u6001+\u8fd9\u6b21\u91cd\u5165\u7684\u5199\u72b6\u6001 \u8d85\u8fc7\u4e86 \u540c\u6b65\u72b6\u6001\u76840~15\u4f4d \u5219\u629b\u51fa\u5f02\u5e38\n        if (w + exclusiveCount(acquires) > MAX_COUNT)\n            throw new Error("Maximum lock count exceeded");\n        \n        \/\/\u8bbe\u7f6e\u540c\u6b65\u72b6\u6001 \u56e0\u4e3a\u5199\u72b6\u6001\u5728\u4f4e16\u4f4d\u6240\u4ee5\u4e0d\u7528\u5de6\u79fb (\u91cd\u5165\u7d2f\u52a0)\n        setState(c + acquires);\n        return true;\n    }\n    \n    \/\/\u540c\u6b65\u72b6\u6001\u4e3a0 \u65e0\u9501\u65f6 \n    \/\/writerShouldBlock\u5728\u975e\u516c\u5e73\u9501\u4e0b\u8fd4\u56defalse \u5728\u516c\u5e73\u9501\u4e0b\u67e5\u770b\u662f\u5426\u6709\u524d\u9a71\u4efb\u52a1\n    \/\/\u5982\u679cCAS\u5931\u8d25\u5219\u8fd4\u56defalse\n    if (writerShouldBlock() ||\n        !compareAndSetState(c, c + acquires))\n        return false;\n    \n    \/\/CAS\u6210\u529f\u5219 \u8bbe\u7f6e\u5f53\u524d\u7ebf\u7a0b\u4e3a\u83b7\u5f97\u72ec\u5360\u9501(\u5199\u9501)\u7684\u7ebf\u7a0b\n    setExclusiveOwnerThread(current);\n    return true;\n}<\/code><\/pre>\n
    \u67e5\u770b\u6e90\u7801\u53ef\u4ee5\u77e5\u9053:<\/p>\n
      \n
    1. \u5f53\u6709\u9501\u65f6\uff08\u540c\u6b65\u72b6\u6001\u4e0d\u4e3a0\u60c5\u51b5\uff09\uff0c\u5982\u679c\u53ea\u6709\u8bfb\u9501\uff08\u6ca1\u6709\u5199\u9501\uff09\uff0c\u90a3\u4e48\u76f4\u63a5\u5931\u8d25\uff1b\u5982\u679c\u53ea\u6709\u5199\u9501\u5219\u67e5\u770b\u5f53\u524d\u7ebf\u7a0b\u662f\u5426\u4e3a\u83b7\u53d6\u5199\u9501\u7684\u7ebf\u7a0b\uff08\u91cd\u5165\u60c5\u51b5\uff09<\/strong><\/li>\n
    2. \u5f53\u65e0\u9501\u65f6\u8fdb\u884cCAS\u83b7\u53d6\u5199\u9501\uff0c\u6210\u529f\u5219\u8bbe\u7f6e\u83b7\u53d6\u5199\u9501\u7684\u7ebf\u7a0b\uff0c\u5931\u8d25\u5219\u8fd4\u56de<\/strong><\/li>\n<\/ol>\n
      \u6839\u636e\u6e90\u7801\u5206\u6790\u53ef\u4ee5\u77e5\u9053\uff0c\u5199\u9501\u5141\u8bb8\u91cd\u5165<\/strong>\uff0c\u5e76\u4e14\u83b7\u53d6\u5199\u9501\u65f6\uff0c\u5982\u679c\u6709\u8bfb\u9501\u4f1a\u88ab\u963b\u585e<\/strong><\/p>\n
      \u5199\u9501\u91ca\u653e<\/h4>\n
      \u5199\u9501\u7684\u91ca\u653e\u5b9e\u73b0\u5728sync.tryRelease<\/code>\u4e2d<\/p>\n
      protected final boolean tryRelease(int releases) {\n    \/\/\u5224\u65ad\u5f53\u524d\u7ebf\u7a0b\u662f\u4e0d\u662f\u83b7\u53d6\u5199(\u72ec\u5360)\u9501\u7684\u7ebf\u7a0b\n    if (!isHeldExclusively())\n        throw new IllegalMonitorStateException();\n    \n    \/\/\u65b0\u72b6\u6001\n    int nextc = getState() - releases;\n    \/\/\u5982\u679c\u65b0\u72b6\u6001\u4f4e16\u4f4d\u4e3a0(\u6ca1\u6709\u5199\u9501)\u5c31\u8bbe\u7f6e\u83b7\u53d6\u5199\u9501\u7684\u7ebf\u7a0b\u4e3a\u7a7a,\u7136\u540e\u8bbe\u7f6e\u540c\u6b65\u72b6\u6001,\u518d\u8fd4\u56de\n    boolean free = exclusiveCount(nextc) == 0;\n    if (free)\n        setExclusiveOwnerThread(null);\n    \n    setState(nextc);\n    return free;\n}<\/code><\/pre>\n
      \u91ca\u653e\u5176\u5b9e\u4e5f\u7c7b\u4f3c\uff0c\u53ea\u6709\u5f53\u5199\u72b6\u6001\u4e3a0\u65f6\u624d\u662f\u771f\u6b63\u91ca\u653e\uff0c\u5176\u4ed6\u60c5\u51b5\u90fd\u662f\u6263\u51cf\u91cd\u5165\u6b21\u6570<\/p>\n
      \u8bfb\u9501\u83b7\u53d6<\/h4>\n
      \u8bfb\u9501\u7684\u83b7\u53d6\u4e5f\u5c31\u662f\u5171\u4eab\u5f0f\u7684\u83b7\u53d6<\/p>\n
              protected final int tryAcquireShared(int unused) {\n            \n            Thread current = Thread.currentThread();\n            \/\/\u540c\u6b65\u72b6\u6001\n            int c = getState();\n            \n            \/\/exclusiveCount \u4e3a\u83b7\u53d6\u5199\u9501\u72b6\u6001 \u4f4e16\u4f4d\u5168\u4e0e1\n            \/\/\u5982\u679c\u6709\u5199\u9501 \u5e76\u4e14 \u83b7\u53d6\u5199\u9501\u7684\u7ebf\u7a0b\u4e0d\u662f\u5f53\u524d\u7ebf\u7a0b \u5219\u5931\u8d25(\u8bf4\u660e\u5141\u8bb8\u540c\u4e00\u7ebf\u7a0b\u83b7\u53d6\u5199\u9501\u518d\u83b7\u53d6\u8bfb\u9501)\n            if (exclusiveCount(c) != 0 &&\n                getExclusiveOwnerThread() != current)\n                return -1;\n            \n            \/\/\u83b7\u53d6\u8bfb\u72b6\u6001  (\u540c\u6b65\u72b6\u6001\u53f3\u79fb16\u4f4d)\n            int r = sharedCount(c);\n            \/\/\u8bfb\u6ca1\u88ab\u963b\u585e \u6ca1\u8d85\u8fc7\u6700\u5927\u503c \u4e14CAS\u6210\u529f \u8bb0\u5f55\u4fe1\u606f \u8fd4\u56de\u6210\u529f\n            if (!readerShouldBlock() &&\n                r < MAX_COUNT &&\n                compareAndSetState(c, c + SHARED_UNIT)) {\n                if (r == 0) {\n                    firstReader = current;\n                    firstReaderHoldCount = 1;\n                } else if (firstReader == current) {\n                    firstReaderHoldCount++;\n                } else {\n                    HoldCounter rh = cachedHoldCounter;\n                    if (rh == null || rh.tid != getThreadId(current))\n                        cachedHoldCounter = rh = readHolds.get();\n                    else if (rh.count == 0)\n                        readHolds.set(rh);\n                    rh.count++;\n                }\n                return 1;\n            }\n            return fullTryAcquireShared(current);\n        }<\/code><\/pre>\n
      \u5728\u8bfb\u9501\u4e2d\u5141\u8bb8\u540c\u4e00\u7ebf\u7a0b\u83b7\u53d6\u5199\u9501\u518d\u83b7\u53d6\u8bfb\u9501<\/strong><\/p>\n
      \u5728\u67d0\u4e9b\u573a\u666f\u4e0b\u8981\u5148\u5199\u6570\u636e\u518d\u8bfb\u6570\u636e\uff0c\u6bd4\u5982\uff1a<\/p>\n
        \n
      1. \u83b7\u53d6\u5199\u9501<\/li>\n
      2. \u5199\u6570\u636e<\/li>\n
      3. \u91ca\u653e\u5199\u9501<\/li>\n
      4. \u4f7f\u7528\uff08\u8bfb\uff09\u6570\u636e<\/li>\n<\/ol>\n
        \u8fd9\u6837\u4f1a\u5bfc\u81f4\u91ca\u653e\u5b8c\u5199\u9501\u540e\uff0c\u5176\u4ed6\u7ebf\u7a0b\u53ef\u4ee5\u83b7\u53d6\u5199\u9501\uff0c\u4ece\u800c\u5bfc\u81f4\u7b2c\u56db\u6b65\u4f1a\u51fa\u73b0\u810f\u8bfb<\/p>\n
        \u6b63\u786e\u7684\u7528\u6cd5\u5e94\u8be5\u5728\u91ca\u653e\u5199\u9501\u524d\u83b7\u53d6\u8bfb\u9501\uff1a<\/p>\n
          \n
        1. \u83b7\u53d6\u5199\u9501<\/li>\n
        2. \u5199\u6570\u636e<\/li>\n
        3. \u83b7\u53d6\u8bfb\u9501<\/li>\n
        4. \u91ca\u653e\u5199\u9501<\/li>\n
        5. \u8bfb\u6570\u636e<\/li>\n<\/ol>\n
          \u8fd9\u6837\u5176\u4ed6\u7ebf\u7a0b\u83b7\u53d6\u5199\u9501\u65f6\u56e0\u4e3a\u90fd\u8bfb\u9501\u4f1a\u88ab\u963b\u585e\uff0c\u800c\u5176\u4ed6\u7ebf\u7a0b\u9700\u8981\u8bfb\u65f6\u53c8\u4e0d\u4f1a\u88ab\u963b\u585e<\/p>\n
          \u5728\u8bfb\u591a\u5199\u5c11\u7684\u573a\u666f\uff0c\u8bfb\u5199\u9501\u7c92\u5ea6\u66f4\u7ec6\uff0c\u8bfb\u8bfb\u4e0d\u963b\u585e\uff0c\u5e76\u53d1\u6027\u80fd\u66f4\u597d<\/strong><\/p>\n
          \u4fe1\u53f7\u91cf<\/h3>\n
          \u529f\u80fd<\/h4>\n
          \u4fe1\u53f7\u91cf\u7528\u4e8e\u63a7\u5236\u540c\u65f6\u8bbf\u95ee\u8d44\u6e90\u7684\u7ebf\u7a0b\u6570\u91cf<\/strong><\/p>\n
          \u7ebf\u7a0b\u8bbf\u95ee\u8d44\u6e90\u65f6\u9700\u8981\u5148\u62ff\u5230\u4fe1\u53f7\u91cf\u624d\u80fd\u8bbf\u95ee\uff0c\u8bbf\u95ee\u5b8c\u91ca\u653e\u4fe1\u53f7\u91cf\uff0c\u4fe1\u53f7\u91cf\u5141\u8bb8\u540c\u65f6N\u4e2a\u7ebf\u7a0b\u83b7\u53d6<\/strong><\/p>\n
          \u4e0b\u9762\u662f\u63a7\u5236\u540c\u65f6\u53ea\u80fd\u67092\u4e2a\u7ebf\u7a0b\u83b7\u53d6\u5230\u4fe1\u53f7\u91cf<\/p>\n
                  \/\/\u521d\u59cb\u5316\u4fe1\u53f7\u91cf\n        Semaphore semaphore = new Semaphore(2);\n        \n        \/\/\u6bcf\u6b21\u53ea\u6709\u4e24\u4e2a\u7ebf\u7a0b\u80fd\u591f\u83b7\u53d6\u5230\u4fe1\u53f7\u91cf\u6267\u884c\n        ExecutorService executor =  Executors.newFixedThreadPool(4);\n        for (int i = 0; i < 10; i++) {\n            executor.execute(()->{\n                try {\n                    semaphore.acquire();\n                    System.out.println(Thread.currentThread().getName()+"\u83b7\u5f97\u8d44\u6e90");\n\n                    \/\/\u6267\u884c\u4efb\u52a1\n                    TimeUnit.SECONDS.sleep(2);\n                } catch (InterruptedException e) {\n                    e.printStackTrace();\n                }finally {\n                    System.out.println(Thread.currentThread().getName()+"\u91ca\u653e\u8d44\u6e90======");\n                    semaphore.release();\n                }\n            });\n        }\n\n        executor.shutdown();<\/code><\/pre>\n
          \u5b9e\u73b0<\/h4>\n
          \u719f\u6089AQS\u7684\u540c\u5b66\u5e94\u8be5\u53ef\u4ee5\u731c\u5230\u4fe1\u53f7\u91cf\u5176\u5b9e\u5c31\u662f\u901a\u8fc7\u5171\u4eab\u5f0f\u5b9e\u73b0\u7684<\/p>\n
          \u4fe1\u53f7\u91cf\u6784\u9020\u65f6\u63d0\u4f9b\u521d\u59cb\u5316\u4fe1\u53f7\u91cf\u7684\u6570\u91cf\uff0c\u5b9e\u9645\u4e0a\u5c31\u662f\u521d\u59cb\u5316\u540c\u6b65\u72b6\u6001\uff0c\u6bd4\u5982\u8bbe\u7f6e2\u4e2a\u4fe1\u53f7\u91cf\u5c31\u662f\u8bbe\u7f6e\u540c\u6b65\u72b6\u6001\u4e3a2\uff1b\u8fd8\u53ef\u4ee5\u5728\u6784\u9020\u4e2d\u8bbe\u7f6e\u516c\u5e73\u3001\u975e\u516c\u5e73<\/p>\n
          \u5728\u83b7\u53d6\u4fe1\u53f7\u91cf\u65f6\uff0c\u4f7f\u7528\u54cd\u5e94\u4e2d\u65ad\u7684\u5171\u4eab\u5f0f\uff0c\u5728\u975e\u516c\u5e73\u60c5\u51b5\u4e0b\u6267\u884cnonfairTryAcquireShared<\/code><\/p>\n
                  final int nonfairTryAcquireShared(int acquires) {\n            for (;;) {\n                \/\/\u83b7\u53d6\u540c\u6b65\u72b6\u6001\n                int available = getState();\n                \/\/\u76ee\u6807\u540c\u6b65\u72b6\u6001 \n                int remaining = available - acquires;\n                \/\/\u6ca1\u6709\u4fe1\u53f7\u91cf \u6216 CAS\u6210\u529f \u90fd\u4f1a\u8fd4\u56de\u76ee\u6807\u540c\u6b65\u72b6\u6001 \u4e3a\u8d1f\u6570\u65f6\u83b7\u53d6\u5931\u8d25\n                if (remaining < 0 ||\n                    compareAndSetState(available, remaining))\n                    return remaining;\n            }\n        }<\/code><\/pre>\n
          \u5728\u83b7\u53d6\u65f6\u5b9e\u9645\u4e0a\u5c31\u662f\u6263\u51cf\u8981\u83b7\u53d6\u7684\u4fe1\u53f7\u91cf\uff0c\u53ef\u80fd\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u83b7\u53d6\u4fe1\u53f7\u91cf\uff0c\u4f7f\u7528CAS+\u5931\u8d25\u91cd\u8bd5\u4fdd\u8bc1\u539f\u5b50\u6027\uff0c\u76f4\u5230\u6ca1\u6709\u4fe1\u53f7\u91cf\u6216CAS\u6210\u529f<\/strong><\/p>\n
          \u5728\u91ca\u653e\u4fe1\u53f7\u91cf\u65f6\u5b9e\u9645\u5c31\u662f\u52a0\u4e0a\u91ca\u653e\u7684\u4fe1\u53f7\u91cf\uff0c\u53ef\u80fd\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u91ca\u653e\u4fe1\u53f7\u91cf\uff0c\u56e0\u6b64\u91ca\u653e\u65f6\u4f7f\u7528CAS+\u5931\u8d25\u91cd\u8bd5\u4fdd\u8bc1\u539f\u5b50\u6027<\/strong><\/p>\n
                  protected final boolean tryReleaseShared(int releases) {\n            for (;;) {\n                int current = getState();\n                int next = current + releases;\n                if (next < current) \/\/ overflow\n                    throw new Error("Maximum permit count exceeded");\n                if (compareAndSetState(current, next))\n                    return true;\n            }\n        }<\/code><\/pre>\n
          CountDownLatch<\/h3>\n
          CountDownLatch \u76f8\u5f53\u4e8e\u4e00\u4e2a\u8ba1\u6570\u5668\uff0c\u5728\u6784\u9020\u65f6\u8bbe\u7f6e\u8ba1\u6570\u6570\u91cf<\/p>\n
          \u529f\u80fd<\/h4>\n
          \u8c03\u7528countDown<\/code>\u65b9\u6cd5\u4f1a\u5bf9\u6570\u91cf\u8fdb\u884c\u81ea\u51cf<\/p>\n
          \u8c03\u7528await<\/code>\u65b9\u6cd5\u65f6\uff0c\u5982\u679c\u8fd8\u6709\u6570\u91cf\u6ca1\u88ab\u6263\u51cf\u5b8c\uff0c\u5219\u4f1a\u963b\u585e\uff0c\u76f4\u5230\u6570\u91cf\u90fd\u88ab\u6263\u51cf\u5b8c<\/p>\n
          \u5f53\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884cN\u4e2a\u4efb\u52a1\uff0c\u6216\u8005\u591a\u4e2a\u7ebf\u7a0b\u6267\u884c\u4e00\u4e2a\u4efb\u52a1\u65f6\uff0c\u8981\u7b49\u5f85\u5b83\u4eec\u6267\u884c\u5b8c\u518d\u8fdb\u884c\u4e0b\u4e00\u6b65\u64cd\u4f5c\u65f6\uff0c\u5c31\u53ef\u4ee5\u4f7f\u7528CountDownLatch<\/p>\n
          \/\/\u521d\u59cb\u531610\nCountDownLatch countDownLatch = new CountDownLatch(10);\n\/\/\u56fa\u5b9a\u7ebf\u7a0b\u6c60\nExecutorService executor = Executors.newFixedThreadPool(10);\nfor (int i = 1; i <= 10; i++) {\n    final int index = i;\n    executor.execute(() -> {\n        System.out.println(Thread.currentThread() + "\u5904\u7406\u4efb\u52a1" + index);\n        \n        \/\/\u6267\u884c\u4efb\u52a1...\n        \n        \/\/\u6570\u91cf-1\n        countDownLatch.countDown();\n    });\n}\n\n\n\/\/\u8ba1\u6570\u91cf\u4e3a0\u65f6\u624d\u53ef\u4ee5\u7ee7\u7eed\u6267\u884c\ncountDownLatch.await();\nSystem.out.println("\u5904\u7406\u5b8c\u4efb\u52a1");\n\nexecutor.shutdown();<\/code><\/pre>\n
          \u5b9e\u73b0<\/h4>\n
          \u5176\u5b9e\u5b83\u7684\u5b9e\u73b0\u4e0e\u4fe1\u53f7\u91cf\u7c7b\u4f3c\uff0c\u4e5f\u662f\u901a\u8fc7\u5171\u4eab\u5f0f<\/p>\n
          \u5728\u6784\u9020\u4e2d\u8bbe\u7f6e\u521d\u59cb\u503c\u65f6\uff0c\u5b9e\u9645\u4e0a\u5c31\u662f\u5728\u8bbe\u7f6e\u540c\u6b65\u72b6\u6001<\/strong><\/p>\n
          \u5f53\u6267\u884ccountDown<\/code>\u6263\u51cf\u6570\u91cf\u65f6\uff0c\u5b9e\u9645\u4e0a\u5c31\u662f\u5728\u6263\u51cf\u540c\u6b65\u72b6\u6001 \uff0c\u7531\u4e8e\u53ef\u80fd\u591a\u7ebf\u7a0b\u540c\u65f6\u6267\u884c\uff0c\u4f7f\u7528CAS+\u5931\u8d25\u91cd\u8bd5\u4fdd\u8bc1\u6263\u51cf\u540c\u6b65\u72b6\u6001\u6210\u529f<\/strong><\/p>\n
          protected boolean tryReleaseShared(int releases) {\n    \/\/ Decrement count; signal when transition to zero\n    for (;;) {\n        int c = getState();\n        if (c == 0)\n            return false;\n        int nextc = c-1;\n        if (compareAndSetState(c, nextc))\n            return nextc == 0;\n    }\n}<\/code><\/pre>\n
          \u6267\u884cawait<\/code>\u65f6\uff0c\u5b9e\u9645\u5c31\u662f\u5224\u65ad\u540c\u6b65\u72b6\u6001\u662f\u5426\u4e3a0\uff0c\u4e0d\u662f\u5219\u8bf4\u660e\u6709\u7684\u7ebf\u7a0b\u8fd8\u672a\u6267\u884c\u5b8c\u4efb\u52a1\uff0c\u963b\u585e\u7b49\u5f85<\/p>\n
          protected int tryAcquireShared(int acquires) {\n    return (getState() == 0) ? 1 : -1;\n}<\/code><\/pre>\n
          CyclicBarrier<\/h3>\n
          cyclic Barrier \u662f\u4e00\u4e2a\u53ef\u5faa\u73af\u4f7f\u7528\u7684\u5c4f\u969c\uff0c\u5b83\u5e38\u5e38\u88ab\u7528\u6765\u548ccountdownlatch\u4f5c\u6bd4\u8f83<\/p>\n
          \u5b83\u5c31\u50cf\u4e00\u4e2a\u5c4f\u969c\uff0c\u8ba9\u7ebf\u7a0b\u6267\u884c\u5b8c\u4efb\u52a1\u540e\u9047\u5230\u5c4f\u969c\u963b\u585e\uff0c\u76f4\u5230\u6240\u6709\u7ebf\u7a0b\u90fd\u6267\u884c\u5b8c\u4efb\u52a1\uff08\u90fd\u5230\u8fbe\u5c4f\u969c\uff09\uff0c\u5e76\u4e14\u5b83\u662f\u53ef\u91cd\u590d\u4f7f\u7528\u7684<\/strong><\/p>\n
                  CyclicBarrier cyclicBarrier = new CyclicBarrier(3, () -> {\n            System.out.println("\u6240\u6709\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\u540e,\u4f18\u5148\u6267\u884c\u6784\u9020\u89c4\u5b9a\u7684runnable");\n        });\n\n        Thread t1 = new Thread(() -> {\n            \/\/\u6267\u884c\u4efb\u52a1\n            task(cyclicBarrier);\n        }, "t1");\n\n        Thread t2 = new Thread(() -> {\n            \/\/\u6267\u884c\u4efb\u52a1\n            task(cyclicBarrier);\n        }, "t2");\n\n        Thread t3 = new Thread(() -> {\n            \/\/\u6267\u884c\u4efb\u52a1\n            task(cyclicBarrier);\n        }, "t3");\n\n        t1.start();\n        t2.start();\n        t3.start();<\/code><\/pre>\n
          task\u65b9\u6cd5\u4e2d\u4f1a\u6267\u884cawait\u963b\u585e\u76f4\u5230\u6240\u6709\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c<\/p>\n
          private static void task(CyclicBarrier cyclicBarrier) {\n    System.out.println(Thread.currentThread() + "\u6267\u884c\u4efb\u52a1...");\n\n    try {\n        TimeUnit.SECONDS.sleep(1);\n\n        cyclicBarrier.await();\n        System.out.println("\u6240\u6709\u7ebf\u7a0b\u90fd\u6267\u884c\u5b8c, " + Thread.currentThread() + "\u8d70\u51fa\u5c4f\u969c");\n    } catch (InterruptedException e) {\n        e.printStackTrace();\n    } catch (BrokenBarrierException e) {\n        e.printStackTrace();\n    }\n}<\/code><\/pre>\n
          cyclic barrier\u4f1a\u8bb0\u5f55\u9700\u8981\u591a\u5c11\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\uff0c\u5e76\u4e14\u901a\u8fc7\u4ee3\u6765\u8fbe\u5230\u91cd\u590d\u4f7f\u7528<\/strong><\/p>\n
          \u4f7f\u7528reentrant lock \u5728await\u4e2d\u52a0\u9501\u3001\u89e3\u9501\uff0c\u6bcf\u5f53\u4e00\u4e2a\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\uff08\u6267\u884cawait\u65f6\uff09\uff0c\u90fd\u4f1a\u8fdb\u884c\u81ea\u51cf\uff0c\u5982\u679c\u4e0d\u4e3a0\u4f1a\u963b\u585e\uff0c\u81ea\u51cf\u52300\u65f6\u8bf4\u660e\u6240\u6709\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\uff0c\u5524\u9192\u5176\u4ed6\u7ebf\u7a0b\uff0c\u5e76\u66f4\u65b0\u65b0\u7684\u4ee3<\/strong><\/p>\n
          Exchange<\/h3>\n
          Exchanger\u7528\u4e8e\u7ebf\u7a0b\u95f4\u7684\u534f\u4f5c\uff0c\u53ef\u4ee5\u7528\u6765\u4ea4\u6362\u53d8\u91cf<\/strong><\/p>\n
          Exchanger<String> exchanger = new Exchanger();\n\nnew Thread(() -> {\n    String A = "A";\n    try {\n        \/\/B\n        System.out.println(exchanger.exchange(A));\n    } catch (InterruptedException e) {\n        e.printStackTrace();\n    }\n}).start();\n\nString B = "B";\ntry {\n    \/\/A\n    String A = exchanger.exchange(B);\n    System.out.println("A=" + A + " B=" + B);\n} catch (InterruptedException e) {\n    e.printStackTrace();\n}<\/code><\/pre>\n
          \u5f53\u4e00\u4e2a\u7ebf\u7a0b\u5148\u6267\u884cexchange\u65f6\u4f1a\u7b49\u5f85\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c\uff0c\u7b49\u5230\u53e6\u4e00\u4e2a\u7ebf\u7a0bexchange\u65f6\u5219\u5524\u9192\u7b49\u5f85\u7684\u7ebf\u7a0b<\/p>\n
          \u603b\u7ed3<\/h3>\n
          \u672c\u7bc7\u6587\u7ae0\u56f4\u7ed5\u524d\u7f6e\u77e5\u8bc6AQS\u539f\u7406\uff0c\u6765\u5b9e\u73b0\u81ea\u5b9a\u4e49\u7684\u540c\u6b65\u7ec4\u4ef6\uff0c\u5e76\u5bf9\u5e76\u53d1\u5305\u4e2d\u5e38\u7528\u540c\u6b65\u7ec4\u4ef6\u7684\u529f\u80fd\u548c\u539f\u7406\u8fdb\u884c\u8bf4\u660e<\/p>\n
          \u7ee7\u627fAQS\u540e\uff0c\u53ea\u9700\u8981\u5b9e\u73b0\u5c1d\u8bd5\u83b7\u53d6\u3001\u91ca\u653e\u540c\u6b65\u72b6\u6001\u7b49\u65b9\u6cd5\u5c31\u53ef\u4ee5\u81ea\u5b9a\u4e49\u540c\u6b65\u7ec4\u4ef6<\/strong><\/p>\n
          ReentrantLock \u662f\u7531AQS\u5b9e\u73b0\u7684\u72ec\u5360\u5f0f\u53ef\u91cd\u5165\u9501\uff0c\u521d\u59cb\u503c\u540c\u6b65\u72b6\u6001\u4e3a0\uff1b\u83b7\u53d6\u9501\u65f6\uff0c\u5982\u679c\u662f\u65e0\u9501\u5219\u5c1d\u8bd5CAS\u81ea\u589e\uff0c\u6210\u529f\u5c31\u83b7\u53d6\u4e86\u9501\uff1b\u5982\u679c\u6709\u9501\u5219\u5224\u65ad\u83b7\u53d6\u9501\u7684\u7ebf\u7a0b\u662f\u4e0d\u662f\u5f53\u524d\u7ebf\u7a0b\uff0c\u662f\u5219\u8bf4\u660e\u662f\u53ef\u91cd\u5165\u9501\u81ea\u589e\u6b21\u6570\uff1b\u5728\u91ca\u653e\u9501\u65f6\u7531\u4e8e\u53ef\u91cd\u5165\u7684\u5173\u7cfb\uff0c\u53ea\u6709\u81ea\u51cf\u4e3a0\u624d\u662f\u771f\u6b63\u91ca\u653e\u9501<\/strong><\/p>\n
          ReentrantLock \u8fd8\u63d0\u4f9b\u54cd\u5e94\u4e2d\u65ad\u3001\u8d85\u65f6\u3001\u516c\u5e73\u9501\u7684\u5176\u4ed6\u529f\u80fd\uff0c\u516c\u5e73\u9501\u5b9e\u73b0\u53ea\u9700\u8981\u52a0\u4e0a\u83b7\u53d6\u9501\u7684\u524d\u63d0\uff1a\u5728AQS\u4e2dFIFO\u6392\u961f\uff0c\u524d\u9a71\u8282\u70b9\u4e3a\u9996\u8282\u70b9<\/strong><\/p>\n
          ReentrantReadWriteLock \u63d0\u4f9b\u5171\u4eab\u7684\u8bfb\u9501\u548c\u72ec\u5360\u7684\u5199\u9501\uff0c\u5c06\u9501\u7684\u72b6\u51b5\u66f4\u52a0\u7ec6\u7c92\u5ea6\uff0c\u5c06\u540c\u6b65\u72b6\u6001\u9ad8\u4f4e16\u4f4d\u62c6\u5206\u4e3a\u8bfb\u3001\u5199\u7684\u72b6\u6001\uff0c\u5728\u8bfb\u591a\u5199\u5c11\u7684\u573a\u666f\u5e76\u53d1\u6027\u80fd\u4f1a\u66f4\u597d\uff1b\u5728\u83b7\u53d6\u5199\u9501\u65f6\uff0c\u5982\u679c\u6709\u8bfb\u9501\u90a3\u4e48\u4f1a\u963b\u585e\uff0c\u5982\u679c\u6709\u5199\u9501\u4f1a\u67e5\u770b\u662f\u5426\u4e3a\u53ef\u91cd\u5165\uff1b\u5728\u83b7\u53d6\u8bfb\u9501\u65f6\uff0c\u6ca1\u6709\u5199\u9501\u5c31\u53ef\u4ee5\u83b7\u53d6\uff0c\u5982\u679c\u5199\u9501\u662f\u5f53\u524d\u7ebf\u7a0b\u4e5f\u53ef\u4ee5\u83b7\u53d6<\/strong><\/p>\n
          \u4fe1\u53f7\u91cf\u7528\u4e8e\u63a7\u5236\u7ebf\u7a0b\u8bbf\u95ee\u8d44\u6e90\uff0c\u521d\u59cb\u5316\u81ea\u5b9a\u4e49\u7684\u4fe1\u53f7\u91cf\u6570\u91cf\uff0c\u7ebf\u7a0b\u8bbf\u95ee\u8d44\u6e90\u65f6\u5148\u83b7\u53d6\u4fe1\u53f7\u91cf\uff0c\u83b7\u53d6\u5230\u4fe1\u53f7\u91cf\u624d\u80fd\u591f\u8bbf\u95ee\u8d44\u6e90\uff1b\u4f7f\u7528\u5171\u4eab\u5f0f\u6765\u5b9e\u73b0\uff0c\u7531\u4e8e\u53ef\u80fd\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u83b7\u53d6\u3001\u91ca\u653e\u4fe1\u53f7\u91cf\uff0c\u5728\u5b9e\u73b0\u65f6\u90fd\u9700\u8981\u4f7f\u7528CAS+\u5931\u8d25\u91cd\u8bd5\u4fdd\u8bc1\u539f\u5b50\u6027<\/strong><\/p>\n
          CountDownLatch \u7528\u4e8e\u8ba1\u6570\uff0c\u53ef\u4ee5\u7528\u4e8e\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884cN\u4e2a\u4efb\u52a1\uff0c\u4e5f\u53ef\u4ee5\u7528\u4e8e\u591a\u4e2a\u7ebf\u7a0b\u6267\u884c1\u4e2a\u4efb\u52a1\uff0c\u5f53\u6267\u884c\u5b8c\u4efb\u52a1\u4f7f\u7528countdown \u6765\u5bf9\u540c\u6b65\u72b6\u6001\u8fdb\u884c\u6263\u51cf\uff0c\u6267\u884cawait\u65b9\u6cd5\u65f6\u53ea\u8981\u540c\u6b65\u72b6\u6001\u4e0d\u4e3a0\u5c31\u4f1a\u963b\u585e\u7ebf\u7a0b\uff0c\u76f4\u5230\u6240\u6709\u4efb\u52a1\u6267\u884c\u5b8c\uff08\u5c06\u540c\u6b65\u72b6\u6001\u6263\u51cf\u5b8c\uff09<\/strong><\/p>\n
          CyclicBarrier \u662f\u53ef\u5faa\u73af\u4f7f\u7528\u7684\u5c4f\u969c\uff0c\u7528\u4e8e\u591a\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\u540e\uff0c\u9700\u8981\u7b49\u5f85\u5176\u4ed6\u7ebf\u7a0b\u90fd\u5230\u8fbe\u5c4f\u969c\u624d\u7ee7\u7eed\u6267\u884c\uff1b\u4f7f\u7528reentrant lock \u548c \u4ee3 \u6765\u5b9e\u73b0\uff0c\u8c03\u7528await\u65f6\u81ea\u51cf\uff0c\u5f53\u8ba1\u6570\u4e3a0\u65f6\u8bf4\u660e\u6240\u6709\u7ebf\u7a0b\u5230\u8fbe\u5c4f\u969c\uff0c\u5524\u9192\u5176\u4ed6\u963b\u585e\u7684\u7ebf\u7a0b<\/strong><\/p>\n
          Exchange \u7528\u4e8e\u7ebf\u7a0b\u95f4\u7684\u534f\u4f5c\uff0c\u80fd\u591f\u4ea4\u6362\u7ebf\u7a0b\u95f4\u7684\u53d8\u91cf<\/strong><\/p>\n
          \u6700\u540e\uff08\u4e0d\u8981\u767d\u5ad6\uff0c\u4e00\u952e\u4e09\u8fde\u6c42\u6c42\u62c9~\uff09<\/h3>\n
          \u672c\u7bc7\u6587\u7ae0\u88ab\u6536\u5165\u4e13\u680f \u7531\u70b9\u5230\u7ebf\uff0c\u7531\u7ebf\u5230\u9762\uff0c\u6df1\u5165\u6d45\u51fa\u6784\u5efaJava\u5e76\u53d1\u7f16\u7a0b\u77e5\u8bc6\u4f53\u7cfb<\/a>\uff0c\u611f\u5174\u8da3\u7684\u540c\u5b66\u53ef\u4ee5\u6301\u7eed\u5173\u6ce8\u5594<\/p>\n
          \u672c\u7bc7\u6587\u7ae0\u7b14\u8bb0\u4ee5\u53ca\u6848\u4f8b\u88ab\u6536\u5165 gitee-StudyJava<\/a>\u3001 github-StudyJava<\/a> \u611f\u5174\u8da3\u7684\u540c\u5b66\u53ef\u4ee5stat\u4e0b\u6301\u7eed\u5173\u6ce8\u5594~<\/p>\n
          \u6848\u4f8b\u5730\u5740\uff1a<\/p>\n
          Gitee-JavaConcurrentProgramming\/src\/main\/java\/C_AQSComponent<\/a><\/p>\n
          Github-JavaConcurrentProgramming\/src\/main\/java\/C_AQSComponent<\/a><\/p>\n
          \u6709\u4ec0\u4e48\u95ee\u9898\u53ef\u4ee5\u5728\u8bc4\u8bba\u533a\u4ea4\u6d41\uff0c\u5982\u679c\u89c9\u5f97\u83dc\u83dc\u5199\u7684\u4e0d\u9519\uff0c\u53ef\u4ee5\u70b9\u8d5e\u3001\u5173\u6ce8\u3001\u6536\u85cf\u652f\u6301\u4e00\u4e0b~<\/p>\n
          \u5173\u6ce8\u83dc\u83dc\uff0c\u5206\u4eab\u66f4\u591a\u5e72\u8d27\uff0c\u516c\u4f17\u53f7\uff1a\u83dc\u83dc\u7684\u540e\u7aef\u79c1\u623f\u83dc<\/p>\n
          \u672c\u6587\u7531\u535a\u5ba2\u4e00\u6587\u591a\u53d1\u5e73\u53f0 OpenWrite<\/a> \u53d1\u5e03\uff01<\/p><\/blockquote>\n
          https:\/\/segmentfault.com\/a\/1190000044193350<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
          \u524d\u8a00 \u4e0a\u7bc7\u6587\u7ae010\u5206\u949f\u4ece\u6e90\u7801\u7ea7\u522b\u641e\u61c2AQS\uff08AbstractQueuedSynchronizer\uff09\u8bf4\u5230JUC\u5e76 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10008250","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008250","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10008250"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008250\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10008250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10008250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10008250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}