{"id":201,"date":"2014-08-27T09:33:55","date_gmt":"2014-08-27T01:33:55","guid":{"rendered":"http:\/\/www.codeeel.com\/?p=201"},"modified":"2014-08-27T09:33:55","modified_gmt":"2014-08-27T01:33:55","slug":"java%e9%9b%86%e5%90%88%e6%a1%86%e6%9e%b6%e6%80%bb%e7%bb%93","status":"publish","type":"post","link":"https:\/\/www.codeeel.com\/?p=201","title":{"rendered":"Java\u96c6\u5408\u6846\u67b6\u603b\u7ed3"},"content":{"rendered":"

1\u3001Java\u5bb9\u5668\u7c7b\u5e93\u7684\u7b80\u5316\u56fe<\/h4>\n

\u4e0b\u9762\u662f\u96c6\u5408\u7c7b\u5e93\u66f4\u52a0\u5b8c\u5907\u7684\u56fe\u3002\u5305\u62ec\u62bd\u8c61\u7c7b\u548c\u9057\u7559\u6784\u4ef6\uff08\u4e0d\u5305\u62ecQueue\u7684\u5b9e\u73b0\uff09\uff1a<\/p>\n

\"\"<\/a><\/p>\n

2\u3001ArrayList<\/h4>\n

\u521d\u59cb\u5316\u65f6\u4e0d\u53ef\u6307\u5b9a\u5bb9\u91cf\uff0c\u5982\u679c\u4ee5new ArrayList()\u65b9\u5f0f\u521b\u5efa\u65f6\uff0c\u521d\u59cb\u5bb9\u91cf\u4e3a10\u4e2a\uff1b\u5982\u679c\u4ee5new ArrayList(Collection c)\u521d\u59cb\u5316\u65f6\uff0c\u5bb9\u91cf\u4e3ac.size()*1.1\uff0c\u5373\u589e\u52a010%\u7684\u5bb9\u91cf\uff1b\u5f53\u5411ArrayList\u4e2d\u6dfb\u52a0\u4e00\u4e2a\u5143\u7d20\u65f6\uff0c\u5148\u8fdb\u884c\u5bb9\u5668\u7684\u5bb9\u91cf\u8c03\u6574\uff0c\u5982\u679c\u5bb9\u91cf\u4e0d\u591f\u65f6\uff0c\u5219\u589e\u52a0\u81f3\u539f\u6765\u76841.5\u500d\u52a01\uff0c\u518d\u7136\u540e\u628a\u5143\u7d20\u52a0\u5165\u5230\u5bb9\u5668\u4e2d\uff0c\u5373\u4ee5\u539f\u59cb\u5bb9\u91cf\u76840.5\u500d\u6bd4\u7387\u589e\u52a0\u3002<\/p>\n

3\u3001Vector<\/span><\/p>\n

\u521d\u59cb\u5316\u65f6\u5bb9\u91cf\u53ef\u4ee5\u8bbe\u5b9a\uff0c\u5982\u679c\u4ee5new Vector()\u65b9\u5f0f\u521b\u5efa\u65f6\uff0c\u5219\u521d\u59cb\u5bb9\u91cf\u4e3a10\uff0c\u8d85\u8fc7\u5bb9\u91cf\u65f6\u4ee52\u500d\u5bb9\u91cf\u589e\u52a0\u3002\u5982\u679c\u4ee5new Vector(Collection c)\u65b9\u5f0f\u521b\u5efa\u65f6\uff0c\u521d\u59cb\u5bb9\u91cf\u4e3ac.size()*1.1\uff0c\u8d85\u8fc7\u65f6\u4ee52\u500d\u5bb9\u91cf\u589e\u52a0\u3002\u5982\u679c\u4ee5new Vector(int initialCapacity, int capacityIncrement)\uff0c\u5219\u4ee5capacityIncrement\u5bb9\u91cf\u589e\u52a0\u3002<\/p>\n

4\u3001\u96c6\u5408\u7279\u70b9\uff1a<\/span><\/p>\n

List\uff1a\u4fdd\u8bc1\u4ee5\u67d0\u79cd\u7279\u5b9a\u63d2\u5165\u987a\u5e8f\u6765\u7ef4\u62a4\u5143\u7d20\u987a\u5e8f\uff0c\u5373\u4fdd\u6301\u63d2\u5165\u7684\u987a\u5e8f\uff0c\u53e6\u5916\u5143\u7d20\u53ef\u4ee5\u91cd\u590d\u3002
\nArrayList\uff1a\u662f\u7528\u6570\u7ec4\u5b9e\u73b0\u7684\uff0c\u8bfb\u53d6\u901f\u5ea6\u5feb\uff0c\u63d2\u5165\u4e0e\u5220\u9664\u901f\u5ea6\u6162\uff08\u56e0\u4e3a\u63d2\u5165\u4e0e\u5220\u9664\u65f6\u8981\u79fb\u52a8\u540e\u9762\u7684\u5143\u7d20\uff09\uff0c\u9002\u5408\u4e8e\u968f\u673a\u8bbf\u95ee\u3002
\nVector\uff1a\u529f\u80fd\u4e0eArrayList\u51e0\u4e4e\u76f8\u540c\uff0c\u4e5f\u662f\u4ee5\u6570\u7ec4\u5b9e\u73b0\uff0c\u6dfb\u52a0\uff0c\u5220\u9664\uff0c\u8bfb\u53d6\uff0c\u8bbe\u7f6e\u90fd\u662f\u57fa\u4e8e\u7ebf\u7a0b\u540c\u6b65\u7684\u3002
\nLinkedList\uff1a\u53cc\u5411\u94fe\u8868\u6765\u5b9e\u73b0\uff0c\u5220\u9664\u4e0e\u63d2\u5165\u901f\u5ea6\u5feb\uff0c\u8bfb\u53d6\u901f\u5ea6\u8f83\u6162\uff0c\u56e0\u4e3a\u5b83\u8bfb\u53d6\u65f6\u662f\u4ece\u5934\u5411\u5c3e\uff08\u5982\u679c\u8282\u70b9\u5728\u94fe\u7684\u524d\u534a\u90e8\u5206\uff09\uff0c\u6216\u5c3e\u5411\u5934\uff08\u5982\u679c\u8282\u70b9\u5728\u94fe\u7684\u540e\u534a\u90e8\u5206\uff09\u67e5\u627e\u5143\u7d20\u3002\u56e0\u6b64\u9002\u5408\u4e8e\u5143\u7d20\u7684\u63d2\u5165\u4e0e\u5220\u9664\u64cd\u4f5c\u3002
\nSet\uff1a\u7ef4\u6301\u5b83\u81ea\u5df1\u7684\u5185\u90e8\u6392\u5e8f\uff0c\u968f\u673a\u8bbf\u95ee\u4e0d\u5177\u6709\u610f\u4e49\u3002\u53e6\u5916\u5143\u7d20\u4e0d\u53ef\u91cd\u590d\u3002
\nHashSet\uff1a\u662f\u6700\u5e38\u7528\u7684\uff0c\u67e5\u8be2\u901f\u5ea6\u6700\u5feb\uff0c\u56e0\u4e3a \u5185\u90e8\u4ee5HashMap\u6765\u5b9e\u73b0\uff0c\u6240\u4ee5\u63d2\u5165\u5143\u7d20\u4e0d\u80fd\u4fdd\u6301\u63d2\u5165\u6b21\u5e8f\u3002
\nLinkedHashSet\uff1a\u7ee7\u627f\u4e86HashSet\uff0c\u4fdd\u6301\u5143\u7d20\u7684\u63d2\u5165\u6b21\u5e8f\uff0c\u56e0\u4e3a\u5185\u90e8\u4f7f\u7528LinkedHashMap\u5b9e\u73b0\uff0c\u6240\u4ee5\u80fd\u4fdd\u6301\u5143\u7d20\u63d2\u5165\u6b21\u5e8f\u3002
\nTreeSet\uff1a\u57fa\u4e8eTreeMap\uff0c\u751f\u6210\u4e00\u4e2a\u603b\u662f\u5904\u4e8e\u6392\u5e8f\u72b6\u6001\u7684set\uff0c\u5b83\u5b9e\u73b0\u4e86SortedSet\u63a5\u53e3\uff0c\u5185\u90e8\u4ee5 TreeMap\u6765\u5b9e\u73b0
\nTreeMap\uff1a\u952e\u4ee5\u67d0\u79cd\u6392\u5e8f\u89c4\u5219\u6392\u5e8f\uff0c\u5185\u90e8\u4ee5red-black\uff08\u7ea2-\u9ed1\uff09\u6811\u6570\u636e\u7ed3\u6784\u5b9e\u73b0\uff0c\u5b9e\u73b0\u4e86SortedMap\u63a5\u53e3\uff0c\u5177\u4f53\u53ef\u53c2\u300aRED-BLACK(\u7ea2\u9ed1)\u6811\u7684\u5b9e\u73b0TreeMap\u6e90\u7801\u9605\u8bfb \u300b
\nHashMap: \u4ee5\u54c8\u5e0c\u8868\u6570\u636e\u7ed3\u6784\u5b9e\u73b0\uff0c\u67e5\u627e\u5bf9\u8c61\u65f6\u901a\u8fc7\u54c8\u5e0c\u51fd\u6570\u8ba1\u7b97\u5176\u4f4d\u7f6e\uff0c\u5b83\u662f\u4e3a\u5feb\u901f\u67e5\u8be2\u800c\u8bbe\u8ba1\u7684\uff0c\u5176\u5185\u90e8\u5b9a\u4e49\u4e86\u4e00\u4e2ahash\u8868\u6570\u7ec4\uff08Entry[] table\uff09\uff0c\u5143\u7d20\u4f1a\u901a\u8fc7\u54c8\u5e0c\u8f6c\u6362\u51fd\u6570\u5c06\u5143\u7d20\u7684\u54c8\u5e0c\u5730\u5740\u8f6c\u6362\u6210\u6570\u7ec4\u4e2d\u5b58\u653e\u7684\u7d22\u5f15\uff0c\u5982\u679c\u6709\u51b2\u7a81\uff0c\u5219\u4f7f\u7528\u6563\u5217\u94fe\u8868\u7684\u5f62\u5f0f\u5c06\u6240\u6709\u76f8\u540c\u54c8\u5e0c\u5730\u5740\u7684\u5143\u7d20\u4e32\u8d77\u6765\uff0c\u53ef\u80fd\u901a\u8fc7\u67e5\u770bHashMap.Entry\u7684\u6e90\u7801\u5b83\u662f\u4e00\u4e2a\u5355\u94fe\u8868\u7ed3\u6784\u3002
\nHashtable:\u4e5f\u662f\u4ee5\u54c8\u5e0c\u8868\u6570\u636e\u7ed3\u6784\u5b9e\u73b0\u7684\uff0c\u89e3\u51b3\u51b2\u7a81\u65f6\u4e0eHashMap\u4e5f\u4e00\u6837\u4e5f\u662f\u91c7\u7528\u4e86\u6563\u5217\u94fe\u8868\u7684\u5f62\u5f0f\uff0c\u4e0d\u8fc7\u6027\u80fd\u6bd4HashMap\u8981\u4f4e\u3002
\nLinkedHashMap:\u7ee7\u627fHashMap\uff0c\u5185\u90e8\u5b9e\u4f53LinkedHashMap.Entry\u7ee7\u627f\u81eaHashMap.Entry\uff0cLinkedHashMap.Entry\u5728HashMap.Entry\u7684\u57fa\u7840\u4e0a\u65b0\u589e\u4e86\u4e24\u4e2a\u5b9e\u4f53\u5f15\u7528\uff08Entry before, after\uff09\uff0c\u8fd9\u6837\u5b9e\u4f53\u53ef\u4ee5\u76f8\u4e92\u4e32\u94fe\u8d77\u6765\u5f62\u6210\u94fe\uff0c\u5e76\u4e14\u5728LinkedHashMap\u4e2d\u5c31\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5934\u8282\u70b9\uff08Entry header\uff09\u7528\u6765\u6307\u5411\u5faa\u73af\u53cc\u5411\u94fe\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\uff08\u901a\u8fc7after\u6307\u5411\uff09\u4e0e\u6700\u540e\u4e00\u4e2a\u5143\u7d20\uff08\u901a\u8fc7before\u6307\u5411\uff09\u3002\u5728\u6dfb\u52a0\u4e00\u4e2a\u5143\u7d20\u65f6\uff0c\u5148\u4f1a\u901a\u8fc7\u7236\u7c7bHashMap\u5c06\u5143\u7d20\u52a0\u5165\u5230hash\u8868\u6570\u7ec4\u91cc\uff0c\u7136\u540e\u518d\u4f1a\u5728\u94fe\u5c3e\uff08header.before\u6307\u5411\u4f4d\u7f6e\uff09\u6dfb\u52a0\uff08\u5f53\u7136\u8fd9\u4e00\u8fc7\u7a0b\u53ea\u662f\u8c03\u6574LinkedHashMap.Entry\u5bf9\u8c61\u5185\u90e8\u7684before, after\u800c\u5df2\uff0c\u800c\u4e0d\u662f\u771f\u771f\u521b\u5efa\u4e00\u4e2a\u4ec0\u4e48\u65b0\u7684\u94fe\u8868\u7ed3\u6784\u5411\u91cc\u52a0\u90a3\u6837\uff09\uff1b\u5220\u9664\u5148\u4ecehash\u8868\u6570\u7ec4\u4e2d\u5220\u9664\uff0c\u518d\u5c06\u88ab\u5220\u9664\u7684\u5143\u7d20\u5f7b\u5e95\u7684\u4ece\u53cc\u5411\u94fe\u4e2d\u65ad\u5f00\u3002\u5176\u5b9e\u5728\u94fe\u4e2d\u6dfb\u52a0\u4e0e\u5220\u9664\u64cd\u4f5c\u4e0eLinkedList\u662f\u4e00\u6837\u7684\uff0c\u53ef\u4ee5\u53c2\u8003\u300aJava\u96c6\u5408\u6846\u67b6\u4e4bLinkedList\u53caListIterator\u5b9e\u73b0\u6e90\u7801\u5206\u6790 \u300b<\/p>\n

5\u3001Hashtable\u548cHashMap\u7684\u533a\u522b\uff1a<\/span><\/p>\n

Hashtable\u4e2d\u7684\u65b9\u6cd5\u662f\u540c\u6b65\u7684\uff0c\u800cHashMap\u4e2d\u7684\u65b9\u6cd5\u5728\u7f3a\u7701\u60c5\u51b5\u4e0b\u662f\u975e\u540c\u6b65\u7684\u3002\u5728\u591a\u7ebf\u7a0b\u5e94\u7528\u7a0b\u5e8f\u4e2d\uff0c\u6211\u4eec\u5e94\u8be5\u4f7f\u7528Hashtable\uff1b\u800c\u5bf9\u4e8eHashMap\uff0c\u5219\u9700\u8981\u989d\u5916\u7684\u540c\u6b65\u673a\u5236\u3002\u4f46HashMap\u7684\u540c\u6b65\u95ee\u9898\u53ef\u901a\u8fc7Collections\u7684\u4e00\u4e2a\u9759\u6001\u65b9\u6cd5\u5f97\u5230\u89e3\u51b3\uff1aMap Collections.synchronizedMap(Map m)\uff0c\u5f53\u7136\u4e0e\u53ef\u4ee5\u81ea\u5df1\u5728\u4f7f\u7528\u5730\u65b9\u52a0\u9501\u3002
\n\u5728HashMap\u4e2d\uff0c\u53ef\u4ee5\u5141\u8bb8null\u4f5c\u4e3a\u952e\uff0c\u4e14\u53ea\u53ef\u4ee5\u6709\u4e00\u4e2a\uff0c\u5426\u5219\u8986\u76d6\uff0c\u4f46\u53ef\u4ee5\u6709\u4e00\u4e2a\u6216\u591a\u4e2a\u503c\u4e3anull\u3002\u56e0\u4e3a\u5f53get()\u65b9\u6cd5\u8fd4\u56denull\u503c\u65f6\uff0c\u5373\u53ef\u4ee5\u8868\u793a HashMap\u4e2d\u6ca1\u6709\u8be5\u952e\uff0c\u4e5f\u53ef\u4ee5\u8868\u793a\u8be5\u952e\u6240\u5bf9\u5e94\u7684\u503c\u4e3anull\uff0c\u6240\u4ee5HashMap\u4e0d\u80fd\u7531get()\u65b9\u6cd5\u6765\u5224\u65ad\u5426\u5b58\u5728\u67d0\u4e2a\u952e\uff0c\u800c\u5e94\u8be5\u7528containsKey()\u65b9\u6cd5\u6765\u5224\u65ad\uff1b\u800cHashtable\u4e0d\u5141\u8bb8null\u952e\u4e0enull\u503c\u3002
\nHashTable\u4f7f\u7528Enumeration\uff0cHashMap\u4f7f\u7528Iterator\u3002
\nHashtable\u662fDictionary\u7684\u5b50\u7c7b\uff0cHashMap\u662fMap\u63a5\u53e3\u7684\u4e00\u4e2a\u5b9e\u73b0\u7c7b\uff1b
\nHashTable\u4e2dhash table\u6570\u7ec4\u9ed8\u8ba4\u5927\u5c0f\u662f11\uff0c\u589e\u52a0\u7684\u65b9\u5f0f\u662f int newCapacity = oldCapacity * 2 + 1;,\u5373\u589e\u52a0\u81f32\u500d\uff08\u800c\u4e0d\u662f2\u500d\u52a01\uff0c\u56e0\u4e3a\u6269\u5bb9\u662f\u5728\u589e\u52a0\u5143\u7d20\u524d\u8fdb\u884c\u7684\uff0c\u5728\u6269\u5bb9\u540e\u4f1a\u5c06\u65b0\u589e\u5143\u7d20\u653e\u5165\u5bb9\u5668\u4e2d\uff09\u3002HashMap\u4e2dhash\u6570\u7ec4\u7684\u9ed8\u8ba4\u5927\u5c0f\u662f16\uff0c\u800c\u4e14\u4e00\u5b9a\u662f2\u7684\u591a\u5c11\u6b21\u65b9;\u53e6\u5916\u4e24\u8005\u7684\u9ed8\u8ba4\u8d1f\u8f7d\u56e0\u5b50\u90fd\u662f0.75\u3002
\n\u6c42\u54c8\u5e0c\u5730\u5740\u4e0e\u54c8\u5e0c\u5730\u5740\u8f6chash\u6570\u7ec4\uff08Entry table[]\uff09\u7d22\u5f15\u65b9\u6cd5\u4e0d\u540c\uff1a
\nHashTable\u76f4\u63a5\u4f7f\u7528\u5bf9\u8c61\u7684hashCode\uff1a<\/p>\n

\n
demo.java<\/strong><\/div>\n
\n
int hash = key.hashCode();\/\/\u76f4\u63a5\u4f7f\u7528\u952e\u7684hashCode\u65b9\u6cd5\u6c42\u54c8\u5e0c\u503c\r\n\/\/\u54c8\u5e0c\u5730\u5740\u8f6chash\u6570\u7ec4\u7d22\u5f15\uff0c\u5148\u4f7f\u7528\u6700\u5927\u6b63int\u6570\u4e0e\uff0c\u8fd9\u6837\u5c06\u8d1f\u8f6c\u6b63\u6570\uff0c\u518d\u4e0e\u6570\u7ec4\u957f\u5ea6\u6c42\u6a21\u5f97\u5230\u5b58\u5165\u7684hash\u6570\u7ec4\u7d22\u5f15\u4f4d\u7f6e\r\nint index = (hash & 0x7FFFFFFF) % tab.length;<\/pre>\n<\/div>\n<\/div>\n
\u800cHashMap\u91cd\u65b0\u8ba1\u7b97hash\u503c\uff0c\u800c\u4e14\u7528\u4f4d\u8fd0\u7b97&\u4ee3\u66ff\u6c42\u6a21\uff1a<\/p>\n
\n
demo.java<\/strong><\/div>\n
\n
int hash = hash(k);\r\nint i = indexFor(hash, table.length);\r\n\r\nstatic int hash(Object x) {\r\n\/\/\u4ee5\u952e\u672c\u8eab\u7684hash\u7801\u4e3a\u57fa\u7840\u6c42\u54c8\u5e0c\u5730\u5740\uff0c\u4f46\u770b\u4e0d\u61c2\u662f\u4ec0\u4e48\u610f\u601d\r\n\u3000\u3000int h = x.hashCode();\r\n\u3000\u3000h += ~(h << 9);\r\n\u3000\u3000h ^= (h >>> 14);\r\n\u3000\u3000h += (h << 4);\r\n\u3000\u3000h ^= (h >>> 10);\r\n\u3000\u3000return h;\r\n}\r\nstatic int indexFor(int h, int length) {\r\n\u3000\u3000return h & (length-1);\/\/\u5c06\u54c8\u5e0c\u5730\u5740\u8f6c\u6362\u6210\u54c8\u5e0c\u6570\u7ec4\u4e2d\u5b58\u5165\u7684\u7d22\u5f15\u53f7\r\n}<\/pre>\n<\/div>\n<\/div>\n
HashMap\u5b9e\u73b0\u56fe\uff1a<\/p>\n
\"\"<\/a><\/p>\n
6\u3001\u96c6\u5408\u4e2d\u952e\u503c\u662f\u5426\u5141\u8bb8null\u5c0f\u7ed3<\/h4>\n
List\uff1a\u53ef\u4ee5\u6709\u591a\u4e2anull\uff0c\u53ef\u4ee5\u6709\u91cd\u590d\u503c\u3002
\nHashSet\uff1a\u80fd\u63d2\u5165\u4e00\u4e2anull\uff08\u56e0\u4e3a\u5185\u90e8\u662f\u4ee5 HashMap\u5b9e\u73b0 \uff09\uff0c\u5ffd\u7565\u4e0d\u63d2\u5165\u91cd\u590d\u5143\u7d20\u3002
\nTreeSet\uff1a\u4e0d\u80fd\u63d2\u5165null \uff08\u56e0\u4e3a\u5185\u90e8\u662f\u4ee5 TreeMap \u5b9e\u73b0 \uff09 \uff0c\u5143\u7d20\u4e0d\u80fd\u91cd\u590d\uff0c\u5982\u679c\u5f85\u63d2\u5165\u7684\u5143\u7d20\u5b58\u5728\uff0c\u5219\u5ffd\u7565\u4e0d\u63d2\u5165\uff0c\u5bf9\u5143\u7d20\u8fdb\u884c\u6392\u5e8f\u3002
\nHashMap\uff1a\u5141\u8bb8\u4e00\u4e2anull\u952e\u4e0e\u591a\u4e2anull\u503c\uff0c\u82e5\u91cd\u590d\u952e\uff0c\u5219\u8986\u76d6\u4ee5\u524d\u503c\u3002
\nTreeMap\uff1a\u4e0d\u5141\u8bb8null\u952e(\u5b9e\u9645\u4e0a\u53ef\u4ee5\u63d2\u5165\u4e00\u4e2anull\u952e\uff0c\u5982\u679c\u8fd9\u4e2aMap\u91cc\u53ea\u6709\u4e00\u4e2a\u5143\u7d20\u662f\u4e0d\u4f1a\u62a5\u9519\u7684\uff0c\u56e0\u4e3a\u4e00\u4e2a\u5143\u7d20\u65f6\u6ca1\u6709\u8fdb\u884c\u6392\u5e8f\u64cd\u4f5c\uff0c\u4e5f\u5c31\u4e0d\u4f1a\u62a5\u7a7a\u6307\u9488\u5f02\u5e38\uff0c\u4f46\u5982\u679c\u63d2\u5165\u7b2c\u4e8c\u4e2a\u65f6\u5c31\u4f1a\u7acb\u5373\u62a5\u9519)\uff0c\u4f46\u5141\u8bb8\u591a\u4e2anull\u503c\uff0c\u8986\u76d6\u5df2\u6709\u952e\u503c\u3002
\nHashTable\uff1a\u4e0d\u5141\u8bb8null\u952e\u4e0enull\u503c(\u5426\u5219\u8fd0\u884c\u8fdb\u62a5\u7a7a\u6307\u9488\u5f02\u5e38)\u3002\u4e5f\u4f1a\u8986\u76d6\u4ee5\u91cd\u590d\u503c\u3002\u57fa\u4e8e\u7ebf\u7a0b\u540c\u6b65\u3002<\/p>\n
7\u3001\u5bf9List\u7684\u9009\u62e9\uff1a<\/span><\/p>\n
\u5bf9\u4e8e\u968f\u673a\u67e5\u8be2\u4e0e\u8fed\u4ee3\u904d\u5386\u64cd\u4f5c\uff0c\u6570\u7ec4\u6bd4\u6240\u6709\u7684\u5bb9\u5668\u90fd\u8981\u5feb\u3002
\n\u4ece\u4e2d\u95f4\u7684\u4f4d\u7f6e\u63d2\u5165\u548c\u5220\u9664\u5143\u7d20\uff0cLinkedList\u8981\u6bd4ArrayList\u5feb\uff0c\u7279\u522b\u662f\u5220\u9664\u64cd\u4f5c\u3002
\nVector\u901a\u5e38\u4e0d\u5982ArrayList\u5feb\uff0c\u5219\u4e14\u5e94\u8be5\u907f\u514d\u4f7f\u7528\uff0c\u5b83\u76ee\u524d\u4ecd\u7136\u5b58\u5728\u4e8e\u7c7b\u5e93\u4e2d\u7684\u539f\u56e0\u662f\u4e3a\u4e86\u652f\u6301\u8fc7\u53bb\u7684\u4ee3\u7801\u3002
\n\u6700\u4f73\u5b9e\u8df5\uff1a\u5c06ArrayList\u4f5c\u4e3a\u9ed8\u8ba4\u9996\u9009\uff0c\u53ea\u6709\u5f53\u7a0b\u5e8f\u7684\u6027\u80fd\u56e0\u4e3a\u7ecf\u5e38\u4ecelist\u4e2d\u95f4\u8fdb\u884c\u63d2\u5165\u548c\u5220\u9664\u800c\u53d8\u5dee\u7684\u65f6\u5019\uff0c\u624d\u53bb\u9009\u62e9LinkedList\u3002\u5f53\u7136\u4e86\uff0c\u5982\u679c\u53ea\u662f\u4f7f\u7528\u56fa\u5b9a\u6570\u91cf\u7684\u5143\u7d20\uff0c\u5c31\u5e94\u8be5\u9009\u62e9\u6570\u7ec4\u4e86\u3002<\/p>\n
8\u3001\u5bf9Set\u7684\u9009\u62e9\uff1a<\/span><\/p>\n
HashSet\u7684\u6027\u80fd\u603b\u6bd4TreeSet\u597d(\u7279\u522b\u662f\u6700\u5e38\u7528\u7684\u6dfb\u52a0\u548c\u67e5\u627e\u5143\u7d20\u64cd\u4f5c)\u3002
\nTreeSet\u5b58\u5728\u7684\u552f\u4e00\u539f\u56e0\u662f\uff0c\u5b83\u53ef\u4ee5\u7ef4\u6301\u5143\u7d20\u7684\u6392\u5e8f\u72b6\u6001\uff0c\u6240\u4ee5\u53ea\u6709\u5f53\u4f60\u9700\u8981\u4e00\u4e2a\u6392\u597d\u5e8f\u7684Set\u65f6\uff0c\u624d\u5e94\u8be5\u4f7f\u7528TreeSet\u3002
\n\u5bf9\u4e8e\u63d2\u5165\u64cd\u4f5c\uff0cLinkedHashSet\u6bd4HashSet\u7565\u5fae\u6162\u4e00\u70b9\uff1a\u8fd9\u662f\u7531\u4e8e\u7ef4\u62a4\u94fe\u8868\u6240\u5e26\u6765\u989d\u5916\u5f00\u9500\u9020\u6210\u7684\u3002\u4e0d\u8fc7\uff0c\u56e0\u4e3a\u6709\u4e86\u94fe\u8868\uff0c\u904d\u5386LinkedHashSet\u4f1a\u6bd4HashSet\u66f4\u5feb\u3002<\/p>\n
9\u3001\u5bf9Map\u7684\u9009\u62e9\uff1a<\/span><\/p>\n
Hashtable\u548cHashMap\u7684\u6548\u7387\u5927\u81f4\u76f8\u540c(\u901a\u5e38HashMap\u66f4\u5feb\u4e00\u70b9\uff0c\u6240\u4ee5HashMap\u6709\u610f\u53d6\u4ee3Hashtable)\u3002
\nTreeMap\u901a\u5e38\u6bd4HashMap\u6162\uff0c\u56e0\u4e3a\u8981\u7ef4\u62a4\u6392\u5e8f\u3002
\nHashMap\u6b63\u662f\u4e3a\u5feb\u901f\u67e5\u8be2\u800c\u8bbe\u8ba1\u7684\u3002
\nLinkedHashMap\u6bd4HashMap\u6162\u4e00\u70b9\uff0c\u56e0\u4e3a\u5b83\u7ef4\u62a4\u6563\u5217\u6570\u636e\u7ed3\u6784\u7684\u540c\u65f6\u8fd8\u8981\u7ef4\u62a4\u94fe\u8868\u3002<\/p>\n
10\u3001Stack<\/span><\/p>\n
\u57fa\u4e8e\u7ebf\u7a0b\u5b89\u5168\uff0cStack\u7c7b\u662f\u7528Vector\u6765\u5b9e\u73b0\u7684(public\u3000class Stack extends Vector)\uff0c\u4f46\u6700\u597d\u4e0d\u8981\u7528\u96c6\u5408API\u91cc\u7684\u8fd9\u4e2a\u5b9e\u73b0\u6808\uff0c\u56e0\u4e3a\u5b83\u7ee7\u627f\u4e8eVector\uff0c\u672c\u5c31\u662f\u4e00\u4e2a\u9519\u8bef\u7684\u8bbe\u8ba1\uff0c\u5e94\u8be5\u662f\u4e00\u4e2a\u7ec4\u5408\u7684\u8bbe\u8ba1\u5173\u7cfb\u3002<\/p>\n
11\u3001Iterator\u5bf9ArrayList(LinkedList)\u7684\u64cd\u4f5c\u9650\u5236\uff1a<\/span><\/p>\n
\u521a\u5b9e\u4f8b\u5316\u7684\u8fed\u4ee3\u5668\u5982\u679c\u8fd8\u6ca1\u6709\u8fdb\u884c\u540e\u79fb(next)\u64cd\u4f5c\u662f\u4e0d\u80fd\u9a6c\u4e0a\u8fdb\u884c\u5220\u9664\u4e0e\u4fee\u6539\u64cd\u4f5c\u7684\u3002
\n\u53ef\u4ee5\u7528ListIterator\u5bf9\u96c6\u5408\u8fde\u7eed\u6dfb\u52a0\u4e0e\u4fee\u6539\uff0c\u4f46\u4e0d\u80fd\u8fde\u7eed\u5220\u9664\u3002
\n\u8fdb\u884c\u6dfb\u52a0\u64cd\u4f5c\u540e\u662f\u4e0d\u80fd\u7acb\u5373\u8fdb\u884c\u5220\u9664\u4e0e\u4fee\u6539\u64cd\u4f5c\u7684\u3002
\n\u8fdb\u884c\u5220\u9664\u64cd\u4f5c\u540e\u53ef\u4ee5\u8fdb\u884c\u6dfb\u52a0\uff0c\u4f46\u4e0d\u80fd\u8fdb\u884c\u4fee\u6539\u64cd\u4f5c\u3002
\n\u8fdb\u884c\u4fee\u6539\u540e\u662f\u53ef\u4ee5\u7acb\u5373\u8fdb\u884c\u5220\u9664\u4e0e\u6dfb\u52a0\u64cd\u4f5c\u7684\u3002<\/p>\n
12\u3001hashCode \u4e0eequals<\/span><\/p>\n
\u5f53\u4ee5\u81ea\u5df1\u7684\u5bf9\u8c61\u505a\u4e3aHashMap\u3001HashTable\u3001LinkedHashMap\u3001HashSet \u3001LinkedHashSet \u7684\u952e\u65f6\uff0c\u4e00\u5b9a\u8981\u91cd\u5199hashCode ()\u4e0eequals ()\u65b9\u6cd5\uff0c\u56e0\u4e3aObject\u7684hashCode()\u662f\u8fd4\u56de\u5185\u5b58\u5730\u5740\uff0c\u4e14equals()\u65b9\u6cd5\u4e5f\u662f\u6bd4\u8f83\u5185\u5b58\u5730\u5740\uff0c\u6240\u4ee5\u5f53\u8981\u5728\u8fd9\u4e9bhash\u96c6\u5408\u4e2d\u67e5\u627e\u65f6\uff0c\u5982\u679c\u662f\u53e6\u5916new\u51fa\u7684\u65b0\u5bf9\u8c61\u662f\u67e5\u4e0d\u5230\u7684\uff0c\u9664\u975e\u91cd\u5199\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u3002\u56e0\u4e3aAbstractMap\u7c7b\u7684containsKey(Object key)\u65b9\u6cd5\u5b9e\u73b0\u5982\u4e0b\uff1a<\/p>\n
\n
demo.java<\/strong><\/div>\n
\n
if (e.hash == hash && eq(k, e.key))\/\/\u5148\u6bd4\u5bf9hashcode\uff0c\u518d\u4f7f\u7528equals\r\n    return true;\r\n\r\nstatic boolean eq(Object x, Object y) {\r\n    return x == y || x.equals(y);\r\n}<\/pre>\n<\/div>\n<\/div>\n
String\u5bf9\u8c61\u662f\u53ef\u4ee5\u51c6\u786e\u505a\u4e3a\u952e\u7684\uff0c\u56e0\u4e3a\u5df2\u91cd\u5199\u4e86\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u3002<\/p>\n
\u56e0\u6b64\uff0cJava\u4e2d\u7684\u96c6\u5408\u6846\u67b6\u4e2d\u7684\u54c8\u5e0c\u662f\u4ee5\u4e00\u4e2a\u5bf9\u8c61\u67e5\u627e\u53e6\u5916\u4e00\u4e2a\u5bf9\u8c61\uff0c\u6240\u4ee5\u91cd\u5199hasCode\u4e0eequals\u65b9\u6cd5\u5f88\u91cd\u8981\u3002<\/p>\n
\u91cd\u5199hashCode()\u4e0eequals()\u8fd9\u4e24\u4e2a\u65b9\u6cd5\u662f\u9488\u5bf9\u54c8\u5e0c\u7c7b\uff0c\u81f3\u4e8e\u5176\u5b83\u96c6\u5408\uff0c\u5982\u679c\u8981\u7528public boolean contains(Object o)\u6216containsValue(Object value)\u67e5\u627e\u65f6\uff0c\u53ea\u9700\u8981\u5b9e\u73b0equals()\u65b9\u6cd5\u5373\u53ef\uff0c\u4ed6\u4eec\u90fd\u53ea\u4f7f\u7528\u5bf9\u8c61\u7684 equals\u65b9\u6cd5\u8fdb\u884c\u6bd4\u5bf9\uff0c\u6ca1\u6709\u4f7f\u7528 hashCode\u65b9\u6cd5\u3002<\/p>\n
13\u3001TreeMap\/TreeSet\uff1a<\/span><\/p>\n
\u653e\u5165\u5176\u4e2d\u7684\u5143\u7d20\u4e00\u5b9a\u8981\u5177\u6709\u81ea\u7136\u6bd4\u8f83\u80fd\u529b(\u5373\u8981\u5b9e\u73b0java.lang.Comparable\u63a5\u53e3)\u6216\u8005\u5728\u6784\u9020TreeMap\/TreeSet\u65f6\u4f20\u5165\u4e00\u4e2a\u6bd4\u8f83\u5668(\u5b9e\u73b0java.util.Comparator\u63a5\u53e3)\uff0c\u5982\u679c\u5728\u521b\u5efa\u65f6\u6ca1\u6709\u4f20\u5165\u6bd4\u8f83\u5668\uff0c\u800c\u653e\u5165\u7684\u5143\u7d20\u4e5f\u6ca1\u6709\u81ea\u7136\u6bd4\u8f83\u80fd\u529b\u65f6\uff0c\u4f1a\u51fa\u73b0\u7c7b\u578b\u8f6c\u6362\u9519\u8bef(\u56e0\u4e3a\u5728\u6ca1\u6709\u8f83\u5668\u65f6\uff0c\u4f1a\u8bd5\u7740\u8f6c\u6210Comparable\u578b)\u3002<\/p>\n
\u4e24\u79cd\u6bd4\u8f83\u63a5\u53e3\uff1a<\/p>\n
\n
demo.java<\/strong><\/div>\n
\n
\/\/\u81ea\u7136\u6bd4\u8f83\u5668\r\npublic interface java.lang.Comparable {\r\n    public int compareTo(Object o);\r\n}\r\n\r\npublic interface java.util.Comparator {\r\n    int compare(Object o1, Object o2);\r\n    boolean equals(Object obj);\r\n}\r\n\r\n14\u3001Collection\u6216Map\u7684\u540c\u6b65\u63a7\u5236\uff1a<\/span><\/pre>\n<\/div>\n<\/div>\n
\u53ef\u4ee5\u4f7f\u7528Collections\u7c7b\u7684\u76f8\u5e94\u9759\u6001\u65b9\u6cd5\u6765\u5305\u88c5\u76f8\u5e94\u7684\u96c6\u5408\u7c7b\uff0c\u4f7f\u4ed6\u4eec\u5177\u7ebf\u7a0b\u5b89\u5168\uff0c\u5982public static Collection synchronizedCollection (Collection c)\u65b9\u6cd5\u5b9e\u8d28\u8fd4\u56de\u7684\u662f\u5305\u88c5\u540e\u7684SynchronizedCollection\u5b50\u7c7b\uff0c\u5f53\u7136\u4f60\u4e5f\u53ef\u4ee5\u4f7f\u7528Collections\u7684synchronizedList\u3001synchronizedMap\u3001synchronizedSet\u65b9\u6cd5\u6765\u83b7\u53d6\u4e0d\u540c\u7684\u7ecf\u8fc7\u5305\u88c5\u4e86\u7684\u540c\u6b65\u96c6\u5408\uff0c\u5176\u4ee3\u7801\u7247\u65ad\uff1a<\/p>\n
\n
demo.java<\/strong><\/div>\n
\n
public class Collections {\r\n\r\n    \/\/...\r\n\r\n    static Collection synchronizedCollection(Collection c, Object mutex) {\r\n        return new SynchronizedCollection(c, mutex);\r\n    }\r\n\r\n    public static List synchronizedList(List list) {\r\n        \/\/...\r\n    }\r\n\r\n    static Set synchronizedSet(Set s, Object mutex) {\r\n        \/\/...\r\n    }\r\n\r\n    public static Map synchronizedMap(Map m) {\r\n        return new SynchronizedMap(m);\r\n    }\r\n\r\n    \/\/...\r\n    static class SynchronizedCollection implements Collection, Serializable {\r\n\r\n        Collection c; \/\/ \u5bf9\u54ea\u4e2a\u96c6\u5408\u8fdb\u884c\u540c\u6b65\uff08\u5305\u88c5\uff09\r\n        Object mutex; \/\/ \u5bf9\u8c61\u9501\uff0c\u53ef\u4ee5\u81ea\u5df1\u8bbe\u7f6e\r\n\r\n        \/\/...\r\n        SynchronizedCollection(Collection c, Object mutex) {\r\n            this.c = c;\r\n            this.mutex = mutex;\r\n        }\r\n\r\n        public int size() {\r\n            synchronized (mutex) {\r\n                return c.size();\r\n            }\r\n        }\r\n\r\n        public boolean isEmpty() {\r\n            synchronized (mutex) {\r\n                return c.isEmpty();\r\n            }\r\n        }\r\n        \/\/...\r\n    }\r\n\r\n    static class SynchronizedList extends SynchronizedCollection implements List {\r\n\r\n        List list;\r\n\r\n        SynchronizedList(List list, Object mutex) {\r\n            super(list, mutex);\r\n            this.list = list;\r\n        }\r\n\r\n        public Object get(int index) {\r\n            synchronized (mutex) {\r\n                return list.get(index);\r\n            }\r\n        }\r\n        \/\/...\r\n    }\r\n\r\n    static class SynchronizedSet extends SynchronizedCollection implements Set {\r\n        SynchronizedSet(Set s) {\r\n            super(s);\r\n        }\r\n        \/\/...\r\n    }\r\n    \/\/...\r\n}<\/pre>\n<\/div>\n<\/div>\n
\u7531\u5305\u88c5\u7684\u4ee3\u7801\u53ef\u4ee5\u770b\u51fa\u53ea\u662f\u628a\u539f\u96c6\u5408\u7684\u76f8\u5e94\u65b9\u6cd5\u653e\u5728\u540c\u6b65\u5757\u91cc\u8c03\u7528\u7f62\u4e86\u3002<\/p>\n
 <\/p>\n
15\u3001\u901a\u8fc7\u8fed\u4ee3\u5668\u4fee\u6539\u96c6\u5408\u7ed3\u6784<\/span><\/p>\n
\u5728\u4f7f\u7528\u8fed\u4ee3\u5668\u904d\u5386\u96c6\u5408\u65f6\uff0c\u6211\u4eec\u4e0d\u80fd\u901a\u8fc7\u96c6\u5408\u672c\u8eab\u6765\u4fee\u6539\u96c6\u5408\u7684\u7ed3\u6784\uff08\u6dfb\u52a0\u3001\u5220\u9664\uff09\uff0c\u53ea\u80fd\u901a\u8fc7\u8fed\u4ee3\u5668\u6765\u64cd\u4f5c\uff0c\u4e0b\u9762\u662f\u62ff\u5bf9HashMap\u5220\u9664\u64cd\u4f5c\u7684\u6d4b\u8bd5\uff0c\u5176\u5b83\u96c6\u5408\u4e5f\u662f\u8fd9\u6837\uff1a<\/p>\n
\n
demo.java<\/strong><\/div>\n
\n
public static void main(String[] args) {\r\n Map map = new HashMap();\r\n map.put(1, 1);\r\n map.put(2, 3);\r\n Set entrySet = map.entrySet();\r\n Iterator it = entrySet.iterator();\r\n while (it.hasNext()) {\r\n  Entry entry = (Entry) it.next();\r\n  \/*\r\n   * \u53ef\u4ee5\u901a\u8fc7\u8fed\u4ee3\u5668\u6765\u4fee\u6539\u96c6\u5408\u7ed3\u6784\uff0c\u4f46\u524d\u63d0\u662f\u8981\u5728\u5df2\u6267\u884c\u8fc7 next \u6216\r\n   * \u524d\u79fb\u64cd\u4f5c\uff0c\u5426\u5219\u4f1a\u629b\u5f02\u5e38\uff1aIllegalStateException\r\n   *\/\r\n  \/\/ it.remove();\r\n  \/*\r\n   * \u629b\u5f02\u5e38\uff1aConcurrentModificationException \u56e0\u4e3a\u901a\u8fc7 \u8fed\u4ee3 \u5668\u64cd\r\n   * \u4f5c\u65f6\uff0c\u4e0d\u80fd\u4f7f\u7528\u96c6\u5408\u672c\u8eab\u6765\u4fee\r\n   * \u6539\u96c6\u5408\u7684\u7ed3\u6784\r\n   *\/\r\n  \/\/ map.remove(entry.getKey());\r\n }\r\n System.out.println(map);\r\n}<\/pre>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
1\u3001Java\u5bb9\u5668\u7c7b\u5e93\u7684\u7b80\u5316\u56fe \u4e0b\u9762\u662f\u96c6\u5408\u7c7b\u5e93\u66f4\u52a0\u5b8c\u5907\u7684\u56fe\u3002\u5305\u62ec\u62bd\u8c61\u7c7b\u548c\u9057\u7559\u6784\u4ef6\uff08\u4e0d\u5305\u62ecQueue\u7684\u5b9e\u73b0\uff09\uff1a 2\u3001ArrayList \u521d\u59cb\u5316\u65f6\u4e0d\u53ef\u6307\u5b9a\u5bb9\u91cf\uff0c\u5982\u679c\u4ee5new ArrayList()\u65b9\u5f0f\u521b\u5efa\u65f6\uff0c\u521d\u59cb\u5bb9\u91cf\u4e3a10\u4e2a\uff1b\u5982\u679c\u4ee5new ArrayList(Collection c)\u521d\u59cb\u5316\u65f6\uff0c\u5bb9\u91cf\u4e3ac.size()*1.1<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[117,120,119,116,121,118],"_links":{"self":[{"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/posts\/201"}],"collection":[{"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=201"}],"version-history":[{"count":1,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/posts\/201\/revisions"}],"predecessor-version":[{"id":204,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=\/wp\/v2\/posts\/201\/revisions\/204"}],"wp:attachment":[{"href":"https:\/\/www.codeeel.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=201"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=201"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.codeeel.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}