{"id":2214,"date":"2020-08-30T12:53:38","date_gmt":"2020-08-30T04:53:38","guid":{"rendered":"http:\/\/127.0.0.2\/?p=2214"},"modified":"2020-09-04T09:00:00","modified_gmt":"2020-09-04T01:00:00","slug":"2020java%e6%95%99%e7%a8%8b%ef%bc%9a%e9%ab%98%e7%ba%a7%e5%a4%9a%e7%ba%bf%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/www.9713job.com\/?p=2214","title":{"rendered":"2020java\u6559\u7a0b\uff1a\u9ad8\u7ea7\u591a\u7ebf\u7a0b"},"content":{"rendered":"

\u9ad8\u7ea7\u591a\u7ebf\u7a0b<\/h3>\n

\u7ebf\u7a0b\u6c60\u6982\u5ff5<\/strong>\uff1a
\n\u73b0\u6709\u95ee\u9898\uff1a
\n\u7ebf\u7a0b\u662f\u5b9d\u8d35\u7684\u5185\u5b58\u8d44\u6e90\u3001\u5355\u4e2a\u7ebf\u7a0b\u7ea6\u53601MB\u7a7a\u95f4\uff0c\u8fc7\u591a\u5206\u914d\u6613\u9020\u6210\u5185\u5b58\u6ea2\u51fa\u3002
\n\u9891\u7e41\u7684\u521b\u5efa\u53ca\u9500\u6bc1\u7ebf\u7a0b\u4f1a\u589e\u52a0\u865a\u62df\u673a\u56de\u6536\u9891\u7387\u3001\u8d44\u6e90\u5f00\u9500\uff0c\u9020\u6210\u7a0b\u5e8f\u6027\u80fd\u4e0b\u964d\u3002<\/p>\n

\u7ebf\u7a0b\u6c60<\/strong>\uff1a
\n\u7ebf\u7a0b\u5bb9\u5668\uff0c\u53ef\u8bbe\u5b9a\u7ebf\u7a0b\u5206\u914d\u7684\u6570\u91cf\u4e0a\u9650\u3002
\n\u5c06\u9884\u5148\u521b\u5efa\u7684\u7ebf\u7a0b\u5bf9\u8c61\u5b58\u5165\u6c60\u4e2d\uff0c\u5e76\u91cd\u7528\u7ebf\u7a0b\u6c60\u4e2d\u7684\u7ebf\u7a0b\u5bf9\u8c61\u3002
\n\u907f\u514d\u9891\u7e41\u7684\u521b\u5efa\u548c\u9500\u6bc1\u3002<\/p>\n

\u7ebf\u7a0b\u6c60\u539f\u7406<\/strong>\uff1a
\n\"\"<\/p>\n

\u5c06\u4efb\u52a1\u63d0\u4ea4\u7ed9\u7ebf\u7a0b\u6c60\uff0c\u7531\u7ebf\u7a0b\u6c60\u5206\u914d\u7ebf\u7a0b\u3001\u8fd0\u884c\u4efb\u52a1\uff0c\u5e76\u5728\u5f53\u524d\u4efb\u52a1\u7ed3\u675f\u540e\u590d\u7528\u7ebf\u7a0b\u3002<\/p>\n

\u83b7\u53d6\u7ebf\u7a0b\u6c60<\/strong>\uff1a
\n\u5e38\u7528\u7684\u7ebf\u7a0b\u6c60\u63a5\u53e3\u548c\u7c7b(java.util.concurrent)
\nExecutor\uff1a\u7ebf\u7a0b\u6c60\u7684\u9876\u7ea7\u63a5\u53e3
\nExecutorService:\u7ebf\u7a0b\u6c60\u63a5\u53e3\uff0c\u53ef\u901a\u8fc7submit(Runnable task)\u63d0\u4ea4\u4efb\u52a1\u4ee3\u7801
\nExecutors\u5de5\u5382\u7c7b\uff1a\u901a\u8fc7\u6b64\u7c7b\u53ef\u4ee5\u83b7\u5f97\u4e00\u4e2a\u7ebf\u7a0b\u6c60\u3002
\n\u901a\u8fc7newFixedThreadPool<\/strong>(int nThreads)\u83b7\u53d6\u56fa\u5b9a\u6570\u91cf\u7684\u7ebf\u7a0b\u6c60\u3002
\n\u53c2\u6570\uff1a\u6307\u5b9a\u7ebf\u7a0b\u6c60\u4e2d\u7ebf\u7a0b\u7684\u6570\u91cf\u3002
\n\u901a\u8fc7newCachedThreadPool<\/strong>()\u83b7\u5f97\u52a8\u6001\u6570\u91cf\u7684\u7ebf\u7a0b\u6c60\uff0c\u5982\u4e0d\u591f\u5219\u521b\u5efa\u65b0\u7684\uff0c\u6ca1\u6709\u4e0a\u9650\u3002<\/p>\n

\u7ebf\u7a0b\u6c60\u65b9\u6cd5<\/strong>\uff1a
\npublic static ExecutorService newFixedThreadPool(int nThreads)<\/strong>
\n\u521b\u5efa\u4e00\u4e2a\u7ebf\u7a0b\u6c60\uff0c\u8be5\u7ebf\u7a0b\u6c60\u91cd\u7528\u56fa\u5b9a\u6570\u91cf\u7684\u4ece\u5171\u4eab\u65e0\u754c\u961f\u5217\u4e2d\u8fd0\u884c\u7684\u8fdb\u7a0b\u3002
\n\u5728\u4efb\u4f55\u65f6\u5019\uff0c\u6700\u591anThreads\u7ebf\u7a0b\u5904\u4e8e\u4e3b\u52a8\u5904\u7406\u4efb\u52a1\u3002\u5982\u679c\u6240\u6709\u7ebf\u7a0b\u5904\u4e8e\u6d3b\u52a8\u72b6\u6001\u65f6\u90fd\u4f1a\u63d0\u4ea4\u5176\u4ed6\u4efb\u52a1\uff0c\u5219\u5b83\u4eec\u5c06\u7b49\u5f85\u961f\u5217\u4e2d\u76f4\u5230\u7ebf\u7a0b\u53ef\u7528\u3002
\n\u5982\u679c\u4efb\u4f55\u7ebf\u7a0b\u7531\u4e8e\u5728\u5173\u95ed\u4e4b\u524d\u7684\u6267\u884c\u671f\u95f4\u53d1\u751f\u6545\u969c\u800c\u7ec8\u6b62\uff0c\u5219\u5982\u679c\u9700\u8981\u6267\u884c\u540e\u7eed\u4efb\u52a1\uff0c\u5219\u65b0\u7ebf\u7a0b\u5c06\u5360\u7528\u5b83\u3002
\n\u7ebf\u7a0b\u6c60\u7ebf\u7a0b\u5c06\u5b58\u5728\uff0c\u76f4\u5230\u5b83\u660e\u786e\u5730\u4e3ashutdown\u3002<\/p>\n

public static ExecutorService newCaChedThreadPool()<\/strong>
\n\u521b\u5efa\u4e00\u4e2a\u6839\u636e\u9700\u8981\u521b\u5efa\u65b0\u7ebf\u7a0b\u7684\u7ebf\u7a0b\u6c60\uff0c\u4f46\u5728\u53ef\u7528\u65f6\u5c06\u91cd\u65b0\u4f7f\u7528\u4ee5\u524d\u6784\u9020\u7684\u7ebf\u7a0b\u3002
\n\u8fd9\u4e9b\u7ebf\u7a0b\u6c60\u901a\u5e38\u4f1a\u63d0\u9ad8\u6267\u884c\u8bb8\u591a\u77ed\u6682\u5f02\u6b65\u4efb\u52a1\u7684\u7a0b\u5e8f\u7684\u6027\u80fd\u3002
\n\u8c03\u7528execute\u5c06\u91cd\u7528\u4ee5\u524d\u6784\u9020\u7684\u7ebf\u7a0b(\u5982\u679c\u53ef\u7528)\u3002\u5982\u679c\u6ca1\u6709\u53ef\u7528\u7684\u7ebf\u7a0b\uff0c\u5c06\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u7ebf\u7a0b\u5e76\u5c06\u5176\u6dfb\u52a0\u5230\u6c60\u4e2d\u3002
\n\u672a\u4f7f\u752860\u79d2\u7684\u7ebf\u7a0b\u5c06\u88ab\u7ec8\u6b62\u5e76\u4ece\u7f13\u5b58\u4e2d\u5220\u9664\u3002
\n\u56e0\u6b64\uff0c\u957f\u65f6\u95f4\u4fdd\u6301\u95f2\u7f6e\u7684\u6c60\u5c06\u4e0d\u4f1a\u6d88\u8017\u4efb\u4f55\u8d44\u6e90\u3002
\n\u8bf7\u6ce8\u610f\uff0c\u53ef\u7528\u4f7f\u7528ThreadPoolExecutor\u6784\u9020\u51fd\u6570\u521b\u5efa\u5177\u6709\u76f8\u4f3c\u5c5e\u6027\u4f46\u4e0d\u540c\u8be6\u7ec6\u4fe1\u606f\u7684\u6c60\u3002
\n\u4f8b\u5982\uff0c\u8d85\u65f6\u53c2\u6570<\/p>\n

Callable\u63a5\u53e3<\/strong>
\npublic interface Callable<V>{
\npublic V call() throw Exception;
\n}<\/p>\n

JDK5.0\u52a0\u5165\uff0c\u4e0eRunnable\u63a5\u53e3\u7c7b\u4f3c\uff0c\u5b9e\u73b0\u4e4b\u540e\u4ee3\u8868\u4e00\u4e2a\u7ebf\u7a0b\u4efb\u52a1\u3002
\nCallable\u5177\u6709\u6cdb\u578b\u7684\u8fd4\u56de\u503c\u3001\u53ef\u7528\u58f0\u660e\u5f02\u5e38\u3002<\/p>\n

Future\u63a5\u53e3<\/strong>
\n\u6982\u5ff5\uff1a\u5f02\u6b65\u63a5\u6536ExecutorService.submit()\u6240\u8fd4\u56de\u7684\u72b6\u6001\u7ed3\u679c\uff0c\u5f53\u4e2d\u5305\u542b\u4e86call()\u7684\u8fd4\u56de\u503c
\n\u65b9\u6cd5\uff1a V get() \u4ee5\u963b\u585e\u5f62\u5f0f\u7b49\u5f85Future\u4e2d\u7684\u5f02\u6b65\u5904\u7406\u7ed3\u679c(call()\u7684\u8fd4\u56de\u503c)<\/p>\n

\u7ebf\u7a0b\u7684\u540c\u6b65<\/strong>
\n\u540c\u6b65\uff1a\u5f62\u5bb9\u4e00\u6b21\u65b9\u6cd5\u8c03\u7528\uff0c\u540c\u6b65\u4e00\u65e6\u5f00\u59cb\uff0c\u8c03\u7528\u8005\u5fc5\u987b\u7b49\u5f85\u8be5\u65b9\u6cd5\u8fd4\u56de\uff0c\u624d\u80fd\u7ee7\u7eed\u3002\"\"<\/p>\n

\u7ebf\u7a0b\u7684\u5f02\u6b65<\/strong>
\n\u5f02\u6b65\uff1a\u5f62\u5bb9\u4e00\u6b21\u65b9\u6cd5\u8c03\u7528\uff0c\u5f02\u6b65\u4e00\u65e6\u5f00\u59cb\uff0c\u50cf\u662f\u4e00\u6b21\u6d88\u606f\u4f20\u9012\uff0c\u8c03\u7528\u8005\u544a\u77e5\u4e4b\u540e\u7acb\u523b\u8fd4\u56de\u3002\u4e8c\u8005\u7ade\u4e89\u65f6\u95f4\u7247\uff0c\u5e76\u53d1\u6267\u884c\u3002\"\"<\/p>\n

Lock\u63a5\u53e3<\/strong>
\nJDK5.0\u52a0\u5165\uff0c\u4e0esynchronized\u6bd4\u8f83\uff0c\u663e\u793a\u5b9a\u4e49\uff0c\u7ed3\u6784\u66f4\u7075\u6d3b\u3002
\n\u63d0\u4f9b\u66f4\u591a\u5b9e\u7528\u6027\u65b9\u6cd5\uff0c\u529f\u80fd\u66f4\u5f3a\u5927\u3001\u6027\u80fd\u66f4\u4f18\u8d8a\u3002
\n\u5e38\u7528\u65b9\u6cd5\uff1a
\nvoid lock()\/\/\u83b7\u53d6\u9501\uff0c\u5982\u9501\u88ab\u5360\u7528\uff0c\u5219\u7b49\u5f85
\nboolean tryLock()\/\/\u5c1d\u8bd5\u83b7\u5f97\u9501(\u6210\u529f\u8fd4\u56detrue\uff0c\u5931\u8d25\u8fd4\u56defalse\uff0c\u4e0d\u963b\u585e)
\nvoid unlock()\/\/\u91ca\u653e\u9501<\/p>\n

\u91cd\u5165\u9501<\/strong>
\nReentrantLock:Lock\u63a5\u53e3\u7684\u5b9e\u73b0\u7c7b\uff0c\u4e0esynchronized\u4e00\u6837\u5177\u6709\u4e92\u65a5\u9501\u529f\u80fd
\nprivate Lock locker=new ReentrantLock();\/\/\u521b\u5efa\u91cd\u5165\u9501\u5bf9\u8c61
\nlocker.lock()\uff1b\/\/\u5f00\u542f\u9501
\nlocker.unlock();\/\/\u91ca\u653e\u9501\uff0c\u653e\u5165\u5230finally\u5757\u4e2d<\/p>\n

\u8bfb\u5199\u9501<\/strong>
\nReentrantReaderWriterLock<\/strong>:
\n\u4e00\u79cd\u652f\u6301\u4e00\u5199\u591a\u8bfb\u7684\u540c\u6b65\u9501\uff0c\u8bfb\u5199\u5206\u79bb\uff0c\u53ef\u5206\u522b\u5206\u914d\u8bfb\u9501\u3001\u5199\u9501\u3002
\n\u652f\u6301\u591a\u6b21\u5206\u914d\u8bfb\u9501\uff0c\u4f7f\u591a\u4e2a\u8bfb\u64cd\u4f5c\u53ef\u4ee5\u5e76\u53d1\u6267\u884c\u3002
\n\u4e92\u65a5\u89c4\u5219\uff1a
\n\u5199-\u5199\uff1a\u4e92\u65a5\uff0c\u963b\u585e\u3002
\n\u8bfb-\u5199\uff1a\u4e92\u65a5\uff0c\u8bfb\u963b\u585e\u5199\uff0c\u5199\u963b\u585e\u8bfb\u3002
\n\u8bfb-\u8bfb\uff1a\u4e0d\u4e92\u65a5\u3001\u4e0d\u963b\u585e\u3002
\n\u5728\u8bfb\u64cd\u4f5c\u8fdc\u8fdc\u9ad8\u4e8e\u5199\u64cd\u4f5c\u7684\u73af\u5883\u4e2d\uff0c\u53ef\u5728\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\u7684\u60c5\u51b5\u4e0b\uff0c\u63d0\u9ad8\u8fd0\u884c\u6548\u7387\u3002<\/p>\n

import java.util.concurrent.ExecutorService;\r\nimport java.util.concurrent.Executors;\r\nimport java.util.concurrent.locks.ReentrantReadWriteLock;\r\n\r\npublic class demos{\r\n    public static void main(String[] args) {\r\n        Student s=new Student();\r\n        long start=System.currentTimeMillis();\r\n        ExecutorService es= Executors.newFixedThreadPool(20);\r\n        Thread t1=new Thread(){\r\n            @Override\r\n            public void run() {\r\n                try{s.getAge();}catch (Exception e){}\r\n            }\r\n        };\r\n        Thread t2=new Thread(){\r\n            @Override\r\n            public void run() {\r\n                try{s.setAge(18);}catch (Exception e){}\r\n            }\r\n        };\r\n        for(int i=0;i<2;i++){\r\n            es.submit(t2);\r\n        }\r\n        for(int i=0;i<18;i++){\r\n            es.submit(t1);\r\n        }\r\n        es.shutdown();\r\n        System.out.println(System.currentTimeMillis()-start);\r\n    }\r\n}\r\nclass Student{\r\n    private ReentrantReadWriteLock lock=new ReentrantReadWriteLock();\r\n    ReentrantReadWriteLock.ReadLock rl=lock.readLock();\r\n    ReentrantReadWriteLock.WriteLock wl=lock.writeLock();\r\n    int age;\r\n    public int getAge() throws Exception {\r\n        rl.lock();\r\n        try{\r\n            Thread.sleep(1000);\r\n            return this.age;\r\n        }finally {\r\n            rl.unlock();\r\n        }\r\n    }\r\n    public void setAge(int age) throws Exception {\r\n        wl.lock();\r\n        try{\r\n            Thread.sleep(1000);\r\n            this.age=age;\r\n        }finally {\r\n            wl.unlock();\r\n        }\r\n    }\r\n}<\/pre>\n
\u7ebf\u7a0b\u5b89\u5168\u7684\u96c6\u5408<\/strong>
\nCollection\u4f53\u7cfb\u96c6\u5408\u4e0b\uff0c\u9664Vector\u4ee5\u5916\u7684\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u3002\"\"<\/p>\n
Collections\u4e2d\u7684\u5de5\u5177\u65b9\u6cd5<\/strong>
\nCollections\u5de5\u5177\u7c7b\u4e2d\u63d0\u4f9b\u4e86\u591a\u4e2a\u53ef\u4ee5\u83b7\u5f97\u7ebf\u7a0b\u5b89\u5168\u96c6\u5408\u7684\u65b9\u6cd5\u3002<\/p>\n
public static <T> Collection<T> synchronizedCollection(Collection<T> c)
\npublic static <T> List<T> synchronizedList(List<T> list)
\npublic static <T> Set<T> synchronizedSet(Set<T> s)
\npublic static <K,V>\u00a0 Map<K,V> synchronizedMap(Map<K,V> m)
\npublic static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s)
\npublic static <K,V>\u00a0 SortedMap<K,V> synchronizedSortedMap(SortedMap<K,V> m)
\nJDK1.2\u63d0\u4f9b\uff0c\u63a5\u53e3\u7edf\u4e00\uff0c\u7ef4\u62a4\u6027\u9ad8\uff0c\u4f46\u6027\u80fd\u6ca1\u63d0\u5347\uff0c\u5747\u5df2synchronized\u5b9e\u73b0\u3002<\/p>\n
CopyOnWriteArrayList<\/strong>
\n\u7ebf\u7a0b\u5b89\u5168\u7684ArrayList\uff0c\u52a0\u5f3a\u7248\u8bfb\u5199\u5206\u79bb\u3002
\n\u5199\u6709\u9501\uff0c\u8bfb\u65e0\u9501\uff0c\u8bfb\u5199\u4e4b\u95f4\u4e0d\u963b\u585e\uff0c\u4f18\u5148\u8bfb\u5199\u9501\u3002
\n\u5199\u5165\u65f6\uff0c\u5148copy\u4e00\u4e2a\u5bb9\u6613\u526f\u672c\uff0c\u518d\u6dfb\u52a0\u65b0\u5143\u7d20\uff0c\u6700\u540e\u66ff\u6362\u5f15\u7528\u3002
\n\u4f7f\u7528\u65b9\u5f0f\u4e0eArrayList\u65e0\u5f02\u3002
\nList<Strint> list=new CopyOnWriteArrayList<String>();
\nlist.add(“A”);<\/p>\n
CopyOnWriteArraySet<\/strong>
\n\u7ebf\u7a0b\u5b89\u5168\u7684Set\uff0c\u5e95\u5c42\u4f7f\u7528CopyOnWriteArrayList\u5b9e\u73b0\u3002
\n\u552f\u4e00\u4e0d\u540c\u5728\u4e8e\uff0c\u4f7f\u7528addIfAbsent()\u6dfb\u52a0\u5143\u7d20\uff0c\u4f1a\u904d\u5386\u6570\u7ec4\u3002
\n\u5982\u5b58\u5728\u5143\u7d20\uff0c\u5219\u4e0d\u6dfb\u52a0(\u6254\u6389\u526f\u672c)<\/p>\n
Set<String> set=new CopyOnWriteArraySet<>();\r\nset.add(\"A\");<\/pre>\n
ConcurrentHashMap<\/strong>
\n\u521d\u59cb\u5bb9\u91cf\u9ed8\u8ba4\u4e3a16\u6bb5\uff0c\u4f7f\u7528\u5206\u6bb5\u9501\u8bbe\u8ba1\u3002
\n\u4e0d\u5bf9\u6574\u4e2aMap\u52a0\u9501\uff0c\u800c\u662f\u4e3a\u6bcf\u4e2a\u6bb5\u52a0\u9501\u3002
\n\u5f53\u591a\u4e2a\u5bf9\u8c61\u5b58\u5165\u540c\u4e00\u4e2a\u6bb5\u65f6\uff0c\u624d\u9700\u8981\u4e92\u65a5\u3002
\n\u6700\u7406\u60f3\u72b6\u6001\u4e3a16\u4e2a\u5bf9\u8c61\u5206\u522b\u5b58\u516516\u4e2a\u6bb5\uff0c\u5e76\u884c\u6570\u91cf16.
\n\u4f7f\u7528\u65b9\u5f0f\u4e0eHashMap\u65e0\u5f02\u3002<\/p>\n
Map<String,String> map=new ConcurrentHashMap<>();\r\nmap.put(key,value);<\/pre>\n
\"\"<\/p>\n","protected":false},"excerpt":{"rendered":"
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