{"id":4006,"date":"2019-03-18T14:14:18","date_gmt":"2019-03-18T06:14:18","guid":{"rendered":"http:\/\/www.xttblog.com\/?p=4006"},"modified":"2019-03-18T14:14:18","modified_gmt":"2019-03-18T06:14:18","slug":"%e4%bb%8ecopyonwritearraylist%e7%9a%84%e9%9d%a2%e8%af%95%e9%a2%98%e5%92%8c%e6%ba%90%e7%a0%81%e8%af%b4%e4%bc%98%e7%bc%ba%e7%82%b9%e5%92%8c%e4%bd%bf%e7%94%a8%e5%9c%ba%e6%99%af","status":"publish","type":"post","link":"https:\/\/www.xttblog.com\/?p=4006","title":{"rendered":"\u4eceCopyOnWriteArrayList\u7684\u9762\u8bd5\u9898\u548c\u6e90\u7801\u8bf4\u4f18\u7f3a\u70b9\u548c\u4f7f\u7528\u573a\u666f"},"content":{"rendered":"<p>\n\tCopyOnWriteArrayList \u662f\u4e00\u4e2a\u5e76\u53d1\u5bb9\u5668\u3002\u6709\u5f88\u591a\u4eba\u79f0\u5b83\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u6211\u8ba4\u4e3a\u8fd9\u53e5\u8bdd\u4e0d\u4e25\u8c28\uff0c\u7f3a\u5c11\u4e00\u4e2a\u524d\u63d0\u6761\u4ef6\uff0c\u90a3\u5c31\u662f\u975e\u590d\u5408\u573a\u666f\u4e0b\u64cd\u4f5c\u5b83\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\u3002\n<\/p>\n<p>\n\tCopy-On-Write \u7b80\u79f0 COW\uff0c\u662f\u4e00\u79cd\u7528\u4e8e\u7a0b\u5e8f\u8bbe\u8ba1\u4e2d\u7684\u4f18\u5316\u7b56\u7565\u3002\u5176\u57fa\u672c\u601d\u8def\u662f\uff0c\u4ece\u4e00\u5f00\u59cb\u5927\u5bb6\u90fd\u5728\u5171\u4eab\u540c\u4e00\u4e2a\u5185\u5bb9\uff0c\u5f53\u67d0\u4e2a\u4eba\u60f3\u8981\u4fee\u6539\u8fd9\u4e2a\u5185\u5bb9\u7684\u65f6\u5019\uff0c\u624d\u4f1a\u771f\u6b63\u628a\u5185\u5bb9 Copy \u51fa\u53bb\u5f62\u6210\u4e00\u4e2a\u65b0\u7684\u5185\u5bb9\u7136\u540e\u518d\u6539\uff0c\u8fd9\u662f\u4e00\u79cd\u5ef6\u65f6\u61d2\u60f0\u7b56\u7565\u3002\n<\/p>\n<p>\n\t<img decoding=\"async\" alt=\"CopyOnWriteArrayList \u4f60\u90fd\u4e0d\u77e5\u9053\uff0c\u8fd8\u600e\u4e48\u62ff Offer\" src=\"https:\/\/images.weserv.nl\/?url=https:\/\/wx1.sinaimg.cn\/large\/8fa5dcfcgy1g16wrmc66pj20dj0a4tct.jpg\" style=\"width: 487px;height: 364px\" \/>\n<\/p>\n<p>\n\tJava \u5e76\u53d1\u5305\u63d0\u4f9b\u4e86\u5f88\u591a\u7ebf\u7a0b\u5b89\u5168\u7684\u96c6\u5408\uff0c\u6709\u4e86\u4ed6\u4eec\u7684\u5b58\u5728\uff0c\u4f7f\u5f97\u6211\u4eec\u5728\u591a\u7ebf\u7a0b\u5f00\u53d1\u4e0b\uff0c\u5927\u5927\u7b80\u5316\u4e86\u591a\u7ebf\u7a0b\u5f00\u53d1\u7684\u96be\u5ea6\uff0c\u4f46\u662f\u5982\u679c\u4e0d\u77e5\u9053\u5176\u4e2d\u7684\u539f\u7406\uff0c\u53ef\u80fd\u4f1a\u5f15\u53d1\u610f\u60f3\u4e0d\u5230\u7684\u95ee\u9898\uff0c\u6240\u4ee5\u77e5\u9053\u5176\u4e2d\u7684\u539f\u7406\u8fd8\u662f\u5f88\u6709\u5fc5\u8981\u7684\u3002\n<\/p>\n<p>\n\tCopyOnWrite \u5bb9\u5668\u5373\u5199\u65f6\u590d\u5236\u7684\u5bb9\u5668\u3002\u901a\u4fd7\u7684\u7406\u89e3\u662f\u5f53\u6211\u4eec\u5f80\u4e00\u4e2a\u5bb9\u5668\u6dfb\u52a0\u5143\u7d20\u7684\u65f6\u5019\uff0c\u4e0d\u76f4\u63a5\u5f80\u5f53\u524d\u5bb9\u5668\u6dfb\u52a0\uff0c\u800c\u662f\u5148\u5c06\u5f53\u524d\u5bb9\u5668\u8fdb\u884c Copy\uff0c\u590d\u5236\u51fa\u4e00\u4e2a\u65b0\u7684\u5bb9\u5668\uff0c\u7136\u540e\u65b0\u7684\u5bb9\u5668\u91cc\u6dfb\u52a0\u5143\u7d20\uff0c\u6dfb\u52a0\u5b8c\u5143\u7d20\u4e4b\u540e\uff0c\u518d\u5c06\u539f\u5bb9\u5668\u7684\u5f15\u7528\u6307\u5411\u65b0\u7684\u5bb9\u5668\u3002\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\u6211\u4eec\u53ef\u4ee5\u5bf9 CopyOnWrite \u5bb9\u5668\u8fdb\u884c\u5e76\u53d1\u7684\u8bfb\uff0c\u800c\u4e0d\u9700\u8981\u52a0\u9501\uff0c\u56e0\u4e3a\u5f53\u524d\u5bb9\u5668\u4e0d\u4f1a\u6dfb\u52a0\u4efb\u4f55\u5143\u7d20\u3002\u6240\u4ee5 CopyOnWrite \u5bb9\u5668\u4e5f\u662f\u4e00\u79cd\u8bfb\u5199\u5206\u79bb\u7684\u601d\u60f3\uff0c\u8bfb\u548c\u5199\u4e0d\u540c\u7684\u5bb9\u5668\u3002\n<\/p>\n<p>\n\t\u4e0b\u9762\u6211\u4eec\u770b\u770b\u5b83\u7684 add \u65b9\u6cd5\u7684\u6e90\u7801\uff1a\n<\/p>\n<pre class=\"brush:java;\">\r\npublic boolean add(E e) {\r\n    \/\/1.\u83b7\u5f97\u72ec\u5360\u9501\r\n    final ReentrantLock lock = this.lock;\r\n    lock.lock();\r\n    try {\r\n        Object[] elements = getArray();\/\/2.\u83b7\u5f97Object[]\r\n        int len = elements.length;\/\/3.\u83b7\u5f97elements\u7684\u957f\u5ea6\r\n        Object[] newElements = Arrays.copyOf(elements, len + 1);\/\/4.\u590d\u5236\u5230\u65b0\u7684\u6570\u7ec4\r\n        newElements[len] = e;\/\/5.\u5c06add\u7684\u5143\u7d20\u6dfb\u52a0\u5230\u65b0\u5143\u7d20\r\n        setArray(newElements);\/\/6.\u66ff\u6362\u4e4b\u524d\u7684\u6570\u636e\r\n        return true;\r\n    } finally {\r\n        lock.unlock();\/\/7.\u91ca\u653e\u72ec\u5360\u9501\r\n    }\r\n}\r\nfinal Object[] getArray() {\r\n    return array;\r\n}<\/pre>\n<p>\n\tCopyOnWrite \u7684\u540d\u5b57\u5c31\u662f\u8fd9\u6837\u6765\u7684\u3002\u5728\u5199\u7684\u65f6\u5019\uff0c\u5148 copy \u4e00\u4e2a\uff0c\u64cd\u4f5c\u65b0\u7684\u5bf9\u8c61\u3002\u7136\u540e\u5728\u8986\u76d6\u65e7\u7684\u5bf9\u8c61\uff0c\u4fdd\u8bc1 volatile \u8bed\u4e49\u3002\n<\/p>\n<p>\n\t\u770b\u5b8c\u8fd9\u4e2a\u6e90\u7801\u540e\uff0c\u6211\u4eec\u6765\u770b\u51e0\u4e2a\u5e38\u89c1\u7684\u9762\u8bd5\u9898\u3002\n<\/p>\n<p>\n\tCopyOnWriteArrayList \u6709\u4ec0\u4e48\u4f18\u70b9\uff1f\n<\/p>\n<p>\n\t\u8bfb\u5199\u5206\u79bb\uff0c\u9002\u5408\u5199\u5c11\u8bfb\u591a\u7684\u573a\u666f\u3002\u4f7f\u7528\u4e86\u72ec\u5360\u9501\uff0c\u652f\u6301\u591a\u7ebf\u7a0b\u4e0b\u7684\u5e76\u53d1\u5199\u3002\n<\/p>\n<p>\n\tCopyOnWriteArrayList \u662f\u5982\u4f55\u4fdd\u8bc1\u5199\u65f6\u7ebf\u7a0b\u5b89\u5168\u7684\uff1f\n<\/p>\n<p>\n\t\u56e0\u4e3a\u7528\u4e86 ReentrantLock \u72ec\u5360\u9501\uff0c\u4fdd\u8bc1\u540c\u65f6\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u96c6\u5408\u8fdb\u884c\u4fee\u6539\u64cd\u4f5c\u3002\n<\/p>\n<p>\n\tCopyOnWrite \u600e\u4e48\u7406\u89e3\uff1f\n<\/p>\n<p>\n\t\u5199\u65f6\u590d\u5236\u3002\u5c31\u662f\u5728\u5199\u7684\u65f6\u5019\uff0c\u5148 copy \u4e00\u4e2a\uff0c\u64cd\u4f5c\u65b0\u7684\u5bf9\u8c61\u3002\u7136\u540e\u5728\u8986\u76d6\u65e7\u7684\u5bf9\u8c61\uff0c\u4fdd\u8bc1 volatile \u8bed\u4e49\u3002\u65b0\u6570\u7ec4\u7684\u957f\u5ea6\u7b49\u4e8e\u65e7\u6570\u7ec4\u7684\u957f\u5ea6 + 1\u3002\n<\/p>\n<p>\n\t\u4ece add \u65b9\u6cd5\u7684\u6e90\u7801\u4e2d\u4f60\u53ef\u4ee5\u770b\u51fa &nbsp;CopyOnWriteArrayList \u7684\u7f3a\u70b9\u662f\u4ec0\u4e48\uff1f\n<\/p>\n<p>\n\t\u5360\u7528\u5185\u5b58\uff0c\u5199\u65f6 copy&nbsp;\u6548\u7387\u4f4e\u3002\u56e0\u4e3a CopyOnWrite \u7684\u5199\u65f6\u590d\u5236\u673a\u5236\uff0c\u6240\u4ee5\u5728\u8fdb\u884c\u5199\u64cd\u4f5c\u7684\u65f6\u5019\uff0c\u5185\u5b58\u91cc\u4f1a\u540c\u65f6\u9a7b\u624e\u4e24\u4e2a\u5bf9\u8c61\u7684\u5185\u5b58\uff0c\u65e7\u7684\u5bf9\u8c61\u548c\u65b0\u5199\u5165\u7684\u5bf9\u8c61\uff08\u6ce8\u610f:\u5728\u590d\u5236\u7684\u65f6\u5019\u53ea\u662f\u590d\u5236\u5bb9\u5668\u91cc\u7684\u5f15\u7528\uff0c\u53ea\u662f\u5728\u5199\u7684\u65f6\u5019\u4f1a\u521b\u5efa\u65b0\u5bf9\u8c61\u6dfb\u52a0\u5230\u65b0\u5bb9\u5668\u91cc\uff0c\u800c\u65e7\u5bb9\u5668\u7684\u5bf9\u8c61\u8fd8\u5728\u4f7f\u7528\uff0c\u6240\u4ee5\u6709\u4e24\u4efd\u5bf9\u8c61\u5185\u5b58\uff09\u3002\u5982\u679c\u8fd9\u4e9b\u5bf9\u8c61\u5360\u7528\u7684\u5185\u5b58\u6bd4\u8f83\u5927\uff0c\u6bd4\u5982\u8bf4 200M \u5de6\u53f3\uff0c\u90a3\u4e48\u518d\u5199\u5165 100M \u6570\u636e\u8fdb\u53bb\uff0c\u5185\u5b58\u5c31\u4f1a\u5360\u7528 300M\uff0c\u90a3\u4e48\u8fd9\u4e2a\u65f6\u5019\u5f88\u6709\u53ef\u80fd\u9020\u6210\u9891\u7e41\u7684 Yong GC \u548c Full GC\u3002\n<\/p>\n<p>\n\tget \u7684\u6e90\u7801\u5206\u6790\u3002\n<\/p>\n<pre class=\"brush:java;\">\r\npublic E get(int index) {\r\n    return get(getArray(), index);\r\n}\r\nfinal Object[] getArray() {\r\n    return array;\r\n}<\/pre>\n<p>\n\tget \u65b9\u6cd5\u5f88\u7b80\u5355\u3002\u4f46\u662f\u4f1a\u51fa\u73b0\u4e00\u4e2a\u5f88\u81f4\u547d\u7684\u95ee\u9898\uff0c\u90a3\u5c31\u662f\u4e00\u81f4\u6027\u95ee\u9898\u3002\n<\/p>\n<p>\n\t\u5f53\u6211\u4eec\u83b7\u5f97\u4e86 array \u540e\uff0c\u7531\u4e8e\u6574\u4e2a get \u65b9\u6cd5\u6ca1\u6709\u72ec\u5360\u9501\uff0c\u6240\u4ee5\u53e6\u5916\u4e00\u4e2a\u7ebf\u7a0b\u8fd8\u53ef\u4ee5\u7ee7\u7eed\u6267\u884c\u4fee\u6539\u7684\u64cd\u4f5c\uff0c\u6bd4\u5982\u6267\u884c\u4e86 remove \u7684\u64cd\u4f5c\uff0cremove \u548c add \u4e00\u6837\uff0c\u4e5f\u4f1a\u7533\u8bf7\u72ec\u5360\u9501\uff0c\u5e76\u4e14\u590d\u5236\u51fa\u65b0\u7684\u6570\u7ec4\uff0c\u5220\u9664\u5143\u7d20\u540e\uff0c\u66ff\u6362\u6389\u65e7\u7684\u6570\u7ec4\u3002\u800c\u8fd9\u4e00\u5207 get \u65b9\u6cd5\u662f\u4e0d\u77e5\u9053\u7684\uff0c\u5b83\u4e0d\u77e5\u9053 array \u6570\u7ec4\u5df2\u7ecf\u53d1\u751f\u4e86\u5929\u7ffb\u5730\u8986\u7684\u53d8\u5316\u3002\u5c31\u50cf\u5fae\u4fe1\u4e00\u6837\uff0c\u867d\u7136\u5bf9\u65b9\u5df2\u7ecf\u628a\u4f60\u7ed9\u5220\u4e86\uff0c\u4f46\u662f\u4f60\u4e0d\u77e5\u9053\u3002\u8fd9\u5c31\u662f\u4e00\u4e2a\u4e00\u81f4\u6027\u95ee\u9898\u3002\n<\/p>\n<p>\n\tCopyOnWrite \u5bb9\u5668\u53ea\u80fd\u4fdd\u8bc1\u6570\u636e\u7684\u6700\u7ec8\u4e00\u81f4\u6027\uff0c\u4e0d\u80fd\u4fdd\u8bc1\u6570\u636e\u7684\u5b9e\u65f6\u4e00\u81f4\u6027\u3002\u6240\u4ee5\u5982\u679c\u4f60\u5e0c\u671b\u5199\u5165\u7684\u7684\u6570\u636e\uff0c\u9a6c\u4e0a\u80fd\u8bfb\u5230\uff0c\u8bf7\u4e0d\u8981\u4f7f\u7528 CopyOnWrite \u5bb9\u5668\u3002\n<\/p>\n<p>\n\tset \u65b9\u6cd5\u89e3\u8bfb\u3002\n<\/p>\n<pre class=\"brush:java;\">\r\npublic E set(int index, E element) {\r\n    \/\/(1)\u83b7\u5f97\u72ec\u5360\u9501\r\n    final ReentrantLock lock = this.lock;\r\n    lock.lock();\r\n    try {\r\n        Object[] elements = getArray();\/\/(2)\u83b7\u5f97array\r\n        E oldValue = get(elements, index);\/\/(3)\u6839\u636e\u4e0b\u6807,\u83b7\u5f97\u65e7\u7684\u5143\u7d20\r\n\r\n        if (oldValue != element) {\/\/(4)\u5982\u679c\u65e7\u7684\u5143\u7d20\u4e0d\u7b49\u4e8e\u65b0\u7684\u5143\u7d20\r\n            int len = elements.length;\/\/(5)\u83b7\u5f97\u65e7\u6570\u7ec4\u7684\u957f\u5ea6\r\n            Object[] newElements = Arrays.copyOf(elements, len);\/\/(6)\u590d\u5236\u51fa\u65b0\u7684\u6570\u7ec4\r\n            newElements[index] = element;\/\/(7)\u4fee\u6539\r\n            setArray(newElements);\/\/(8)\u66ff\u6362\r\n        } else {\r\n            \/\/(9)\u4e3a\u4e86\u4fdd\u8bc1volatile \u8bed\u4e49\uff0c\u5373\u4f7f\u6ca1\u6709\u4fee\u6539\uff0c\u4e5f\u8981\u66ff\u6362\u6210\u65b0\u7684\u6570\u7ec4\r\n            \/\/ Not quite a no-op; ensures volatile write semantics\r\n            setArray(elements);\r\n        }\r\n        return oldValue;\r\n    } finally {\r\n        lock.unlock();\/\/(10)\u91ca\u653e\u72ec\u5360\u9501\r\n    }\r\n}<\/pre>\n<p>\n\t\u4e0a\u9762\u7684\u4ee3\u7801\uff0c\u6211\u5199\u7684\u90fd\u6709\u6ce8\u91ca\uff0c\u76f8\u4fe1\u5927\u5bb6\u90fd\u80fd\u770b\u660e\u767d\u3002\n<\/p>\n<p>\n\tset \u7684\u65f6\u5019\uff0c\u540c\u6837\u7684\u4f1a\u83b7\u5f97\u4e00\u4e2a\u72ec\u5360\u9501\uff0c\u6765\u4fdd\u8bc1\u5199\u7684\u7ebf\u7a0b\u5b89\u5168\u3002\u4fee\u6539\u64cd\u4f5c\uff0c\u5b9e\u9645\u4e0a\u64cd\u4f5c\u7684\u662f array \u7684\u4e00\u4e2a\u526f\u672c\uff0c\u6700\u540e\u624d\u628a array \u7ed9\u66ff\u6362\u6389\u3002\u6240\u4ee5\uff0c\u4fee\u6539\u548c add \u5f88\u76f8\u4f3c\u3002set\u3001add\u3001remove \u662f\u4e92\u65a5\u7684\u3002\n<\/p>\n<p>\n\tremove \u65b9\u6cd5\u89e3\u8bfb\u3002\n<\/p>\n<pre class=\"brush:java;\">\r\npublic E remove(int index) {\r\n    final ReentrantLock lock = this.lock;\/\/\u83b7\u5f97\u72ec\u5360\u9501\r\n    lock.lock();\r\n    try {\r\n        Object[] elements = getArray();\r\n        int len = elements.length;\/\/ \u65e7\u6570\u7ec4\u7684\u957f\u5ea6\r\n        E oldValue = get(elements, index);\r\n        int numMoved = len - index - 1;\r\n        if (numMoved == 0)\/\/\u5224\u65ad\u662f\u5426\u662f\u5220\u9664\u6570\u7ec4\u5c3e\u90e8\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\r\n            \/\/\u5219\u590d\u5236\u51fa\u4e00\u4e2a\u957f\u5ea6\u4e3a\u3010\u65e7\u6570\u7ec4\u7684\u957f\u5ea6-1\u3011\u7684\u65b0\u6570\u7ec4\r\n            setArray(Arrays.copyOf(elements, len - 1));\r\n        else {\r\n            \/\/\u5982\u679c\u8981\u5220\u9664\u7684\u5143\u7d20\u4e0d\u662f\u6700\u540e\u4e00\u4e2a\uff0c\u5219\u5206\u4e24\u6b21\u590d\u5236\uff0c\u968f\u4e4b\u66ff\u6362\u3002\r\n            Object[] newElements = new Object[len - 1];\r\n            System.arraycopy(elements, 0, newElements, 0, index);\r\n            System.arraycopy(elements, index + 1, newElements, index,\r\n                             numMoved);\r\n            setArray(newElements);\r\n        }\r\n        return oldValue;\r\n    } finally {\r\n        lock.unlock();\r\n    }\r\n}<\/pre>\n<p>\n\t\u7814\u7a76 java \u81ea\u5e26\u7684\u4e00\u4e9b\u6570\u636e\u7ed3\u6784\uff0c\u4f60\u4f1a\u53d1\u73b0\u8bbe\u8ba1\u7684\u90fd\u5f88\u5de7\u5999\u3002\u5927\u5e08\u5c31\u662f\u5927\u5e08\u554a\u3002\n<\/p>\n<p>\n\t\u8fed\u4ee3\u5668\u7684\u4e3b\u8981\u6e90\u7801\u5982\u4e0b\uff1a\n<\/p>\n<pre class=\"brush:java;\">\r\npublic Iterator&lt;E&gt; iterator() {\r\n    return new COWIterator&lt;E&gt;(getArray(), 0);\r\n}\r\nstatic final class COWIterator&lt;E&gt; implements ListIterator&lt;E&gt; {\r\n    private final Object[] snapshot;\r\n    private int cursor;\r\n    private COWIterator(Object[] elements, int initialCursor) {\r\n        cursor = initialCursor;\r\n        snapshot = elements;\r\n    }\r\n    \/\/ \u5224\u65ad\u662f\u5426\u8fd8\u6709\u4e0b\u4e00\u4e2a\u5143\u7d20\r\n    public boolean hasNext() {\r\n        return cursor &lt; snapshot.length;\r\n    }\r\n    \/\/\u83b7\u53d6\u4e0b\u4e2a\u5143\u7d20\r\n    @SuppressWarnings(&quot;unchecked&quot;)\r\n    public E next() {\r\n        if (! hasNext())\r\n            throw new NoSuchElementException();\r\n        return (E) snapshot[cursor++];\r\n    }\r\n}<\/pre>\n<p>\n\t\u8c03\u7528 iterator \u65b9\u6cd5\u83b7\u53d6\u8fed\u4ee3\u5668\uff0c\u5185\u90e8\u4f1a\u8c03\u7528 COWIterator \u7684\u6784\u9020\u65b9\u6cd5\uff0c\u6b64\u6784\u9020\u65b9\u6cd5\u6709\u4e24\u4e2a\u53c2\u6570\uff0c\u7b2c\u4e00\u4e2a\u53c2\u6570\u5c31\u662f array \u6570\u7ec4\uff0c\u7b2c\u4e8c\u4e2a\u53c2\u6570\u662f\u4e0b\u6807\uff0c\u5c31\u662f 0\u3002\u968f\u540e\u6784\u9020\u65b9\u6cd5\u4e2d\u4f1a\u628a array \u6570\u7ec4\u8d4b\u503c\u7ed9snapshot\u53d8\u91cf\u3002snapshot \u662f&ldquo;\u5feb\u7167&rdquo;\u7684\u610f\u601d\uff0c\u5982\u679c Java \u57fa\u7840\u5c1a\u53ef\u7684\u8bdd\uff0c\u5e94\u8be5\u77e5\u9053\u6570\u7ec4\u662f\u5f15\u7528\u7c7b\u578b\uff0c\u4f20\u9012\u7684\u662f\u6307\u9488\uff0c\u5982\u679c\u6709\u5176\u4ed6\u5730\u65b9\u4fee\u6539\u4e86\u6570\u7ec4\uff0c\u8fd9\u91cc\u5e94\u8be5\u9a6c\u4e0a\u5c31\u53ef\u4ee5\u53cd\u5e94\u51fa\u6765\uff0c\u90a3\u4e3a\u4ec0\u4e48\u53c8\u4f1a\u662f snapshot\u8fd9\u6837\u7684\u547d\u540d\u5462\uff1f\u6ca1\u9519\uff0c\u5982\u679c\u5176\u4ed6\u7ebf\u7a0b\u6ca1\u6709\u5bf9 CopyOnWriteArrayList \u8fdb\u884c\u589e\u5220\u6539\u7684\u64cd\u4f5c\uff0c\u90a3\u4e48 snapshot \u5c31\u662f\u672c\u8eab\u7684 array\uff0c\u4f46\u662f\u5982\u679c\u5176\u4ed6\u7ebf\u7a0b\u5bf9 CopyOnWriteArrayList \u8fdb\u884c\u4e86\u589e\u5220\u6539\u7684\u64cd\u4f5c\uff0c\u65e7\u7684\u6570\u7ec4\u4f1a\u88ab\u65b0\u7684\u6570\u7ec4\u7ed9\u66ff\u6362\u6389\uff0c\u4f46\u662f snapshot \u8fd8\u662f\u539f\u6765\u65e7\u7684\u6570\u7ec4\u7684\u5f15\u7528\u3002\u4e5f\u5c31\u662f\u8bf4 \u5f53\u6211\u4eec\u4f7f\u7528\u8fed\u4ee3\u5668\u4fbf\u5229 CopyOnWriteArrayList \u7684\u65f6\u5019\uff0c\u4e0d\u80fd\u4fdd\u8bc1\u62ff\u5230\u7684\u6570\u636e\u662f\u6700\u65b0\u7684\uff0c\u8fd9\u4e5f\u662f\u4e00\u81f4\u6027\u95ee\u9898\u3002\n<\/p>\n<p>\n\tCopyOnWriteArrayList \u7684\u4f7f\u7528\u573a\u666f\n<\/p>\n<p>\n\t\u901a\u8fc7\u6e90\u7801\u5206\u6790\uff0c\u6211\u4eec\u770b\u51fa\u5b83\u7684\u4f18\u7f3a\u70b9\u6bd4\u8f83\u660e\u663e\uff0c\u6240\u4ee5\u4f7f\u7528\u573a\u666f\u4e5f\u5c31\u6bd4\u8f83\u660e\u663e\u3002\u5c31\u662f\u5408\u9002\u8bfb\u591a\u5199\u5c11\u7684\u573a\u666f\u3002\n<\/p>\n<p>\n\tCopyOnWriteArrayList \u7684\u7f3a\u70b9\n<\/p>\n<ol>\n<li>\n\t\t\u7531\u4e8e\u5199\u64cd\u4f5c\u7684\u65f6\u5019\uff0c\u9700\u8981\u62f7\u8d1d\u6570\u7ec4\uff0c\u4f1a\u6d88\u8017\u5185\u5b58\uff0c\u5982\u679c\u539f\u6570\u7ec4\u7684\u5185\u5bb9\u6bd4\u8f83\u591a\u7684\u60c5\u51b5\u4e0b\uff0c\u53ef\u80fd\u5bfc\u81f4 young gc \u6216\u8005 full gc\u3002\n\t<\/li>\n<li>\n\t\t\u4e0d\u80fd\u7528\u4e8e\u5b9e\u65f6\u8bfb\u7684\u573a\u666f\uff0c\u50cf\u62f7\u8d1d\u6570\u7ec4\u3001\u65b0\u589e\u5143\u7d20\u90fd\u9700\u8981\u65f6\u95f4\uff0c\u6240\u4ee5\u8c03\u7528\u4e00\u4e2a set \u64cd\u4f5c\u540e\uff0c\u8bfb\u53d6\u5230\u6570\u636e\u53ef\u80fd\u8fd8\u662f\u65e7\u7684\uff0c\u867d\u7136CopyOnWriteArrayList \u80fd\u505a\u5230\u6700\u7ec8\u4e00\u81f4\u6027,\u4f46\u662f\u8fd8\u662f\u6ca1\u6cd5\u6ee1\u8db3\u5b9e\u65f6\u6027\u8981\u6c42\u3002\n\t<\/li>\n<li>\n\t\t\u7531\u4e8e\u5b9e\u9645\u4f7f\u7528\u4e2d\u53ef\u80fd\u6ca1\u6cd5\u4fdd\u8bc1 CopyOnWriteArrayList \u5230\u5e95\u8981\u653e\u7f6e\u591a\u5c11\u6570\u636e\uff0c\u4e07\u4e00\u6570\u636e\u7a0d\u5fae\u6709\u70b9\u591a\uff0c\u6bcf\u6b21 add\/set \u90fd\u8981\u91cd\u65b0\u590d\u5236\u6570\u7ec4\uff0c\u8fd9\u4e2a\u4ee3\u4ef7\u5b9e\u5728\u592a\u9ad8\u6602\u4e86\u3002\u5728\u9ad8\u6027\u80fd\u7684\u4e92\u8054\u7f51\u5e94\u7528\u4e2d\uff0c\u8fd9\u79cd\u64cd\u4f5c\u5206\u5206\u949f\u5f15\u8d77\u6545\u969c\u3002\n\t<\/li>\n<\/ol>\n<p>\n\tCopyOnWriteArrayList \u7684\u8bbe\u8ba1\u601d\u60f3\n<\/p>\n<ol>\n<li>\n\t\t\u8bfb\u5199\u5206\u79bb\uff0c\u8bfb\u548c\u5199\u5206\u5f00\n\t<\/li>\n<li>\n\t\t\u6700\u7ec8\u4e00\u81f4\u6027\n\t<\/li>\n<li>\n\t\t\u4f7f\u7528\u53e6\u5916\u5f00\u8f9f\u7a7a\u95f4\u7684\u601d\u8def\uff0c\u6765\u89e3\u51b3\u5e76\u53d1\u51b2\u7a81\n\t<\/li>\n<\/ol>\n<p>\n\t<img decoding=\"async\" alt=\"\u53f2\u4e0a\u6700\u725b\u903c\u7684 Java \u4e2a\u4eba\u7b80\u5386\" src=\"https:\/\/images.weserv.nl\/?url=https:\/\/wx1.sinaimg.cn\/large\/8fa5dcfcgy1g16x4z9ohtj20ea0fjq5q.jpg\" style=\"width: 514px;height: 559px\" \/>\n<\/p>\n<p>\n\t\u4ee5\u4e0a\u5185\u5bb9\u5e0c\u671b\u80fd\u591f\u5728\u9762\u8bd5\u6216\u8005\u5de5\u4f5c\u4e2d\u5e2e\u52a9\u5230\u5927\u5bb6\uff01<\/p>\n<!-- <audio autoplay=\"autoplay\" height=\"100\" width=\"100\" hidden=\"true\"><source src=\"https:\/\/c.coka.la\/orAvPR.mp3\" type=\"audio\/mp3\"\/><\/audio><img decoding=\"async\" src=\"https:\/\/images.weserv.nl\/?url=https:\/\/ws3.sinaimg.cn\/large\/8fa5dcfcgy1g4em3rzar5j20ib089ae0.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/> --><p><!-- <img decoding=\"async\" src=\"https:\/\/raw.githubusercontent.com\/xmt1139057136\/xttblog\/master\/8fa5dcfcgy1g4em3rzar5j20ib089ae0.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/>--><img decoding=\"async\" src=\"https:\/\/saas.51autoparts.cn\/api\/admin\/sys-file\/oss\/file?fileName=84db51f8561e448f9a4fda2eff0811f9.jpg\" alt=\"\u4e1a\u4f59\u8349\u516c\u4f17\u53f7\"\/><\/p><p>\u6700\u540e\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u4e2a\u4eba\u5fae\u4fe1\u516c\u4f17\u53f7\uff1a\u4e1a\u4f59\u8349\uff08yyucao\uff09\uff01<b>\u53ef\u52a0\u4f5c\u8005\u5fae\u4fe1\u53f7\uff1a<font color=\"red\">xttblog2<\/font>\u3002\u5907\u6ce8\uff1a\u201c1\u201d\uff0c\u6dfb\u52a0\u535a\u4e3b\u5fae\u4fe1\u62c9\u4f60\u8fdb\u5fae\u4fe1\u7fa4\u3002\u5907\u6ce8\u9519\u8bef\u4e0d\u4f1a\u540c\u610f\u597d\u53cb\u7533\u8bf7\u3002<\/b>\u518d\u6b21\u611f\u8c22\u60a8\u7684\u5173\u6ce8\uff01\u540e\u7eed\u6709\u7cbe\u5f69\u5185\u5bb9\u4f1a\u7b2c\u4e00\u65f6\u95f4\u53d1\u7ed9\u60a8\uff01\u539f\u521b\u6587\u7ae0\u6295\u7a3f\u8bf7\u53d1\u9001\u81f3532009913@qq.com\u90ae\u7bb1\u3002\u5546\u52a1\u5408\u4f5c\u4e5f\u53ef\u6dfb\u52a0\u4f5c\u8005\u5fae\u4fe1\u8fdb\u884c\u8054\u7cfb\uff01<\/p><p>\u672c\u6587\u539f\u6587\u51fa\u5904\uff1a<a href=\"https:\/\/www.xttblog.com\">\u4e1a\u4f59\u8349<\/a>\uff1a &raquo; <a href=\"https:\/\/www.xttblog.com\/?p=4006\">\u4eceCopyOnWriteArrayList\u7684\u9762\u8bd5\u9898\u548c\u6e90\u7801\u8bf4\u4f18\u7f3a\u70b9\u548c\u4f7f\u7528\u573a\u666f<\/a><\/p><!-- <div class=\"bd-reward-stl\"><button id=\"bdRewardBtn\"><span><\/span><\/button><\/div> -->","protected":false},"excerpt":{"rendered":"<p>CopyOnWriteArrayList \u662f\u4e00\u4e2a\u5e76\u53d1\u5bb9\u5668\u3002\u6709\u5f88\u591a\u4eba\u79f0\u5b83\u662f\u7ebf\u7a0b\u5b89\u5168\u7684\uff0c\u6211\u8ba4\u4e3a\u8fd9\u53e5\u8bdd\u4e0d\u4e25\u8c28\uff0c\u7f3a\u5c11\u4e00 [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[1741,1204,567,568,505],"class_list":["post-4006","post","type-post","status-publish","format-standard","hentry","category-java","tag-arraylist","tag-filelist","tag-java-","tag-568","tag-505"],"_links":{"self":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/4006","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4006"}],"version-history":[{"count":1,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/4006\/revisions"}],"predecessor-version":[{"id":4007,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=\/wp\/v2\/posts\/4006\/revisions\/4007"}],"wp:attachment":[{"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4006"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4006"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xttblog.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4006"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}