{"id":169,"date":"2015-04-12T15:41:20","date_gmt":"2015-04-12T07:41:20","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=169"},"modified":"2026-08-18T12:09:28","modified_gmt":"2026-08-18T04:09:28","slug":"java%e7%9a%84%e6%95%b0%e6%8d%ae%e7%bb%93%e6%9e%84","status":"publish","type":"post","link":"https:\/\/ai.zhousir.top\/?p=169","title":{"rendered":"Java\u7684\u6570\u636e\u7ed3\u6784"},"content":{"rendered":"
\n

\u7ebf\u6027\u8868\u3001\u94fe\u8868\u3001\u54c8\u5e0c\u8868\u662f\u5e38\u7528\u6570\u636e\u7ed3\u6784\u3002\u505a Java \u5f00\u53d1\u65f6\uff0cJDK \u5df2\u7ecf\u5728 java.util<\/code> \u91cc\u51c6\u5907\u597d\u4e86\u4e00\u5957\u7c7b\u3002\u4e0b\u9762\u6309\u63a5\u53e3\u628a\u5404\u81ea\u7684\u804c\u8d23\u548c\u4f7f\u7528\u65b9\u5f0f\u7406\u6e05\u3002<\/p>\n

\u8bb0\u4f4f\u4e24\u68f5\u6811\uff1aCollection<\/strong>\uff08\u5355\u5217\uff09\u548c Map<\/strong>\uff08\u952e\u503c\uff09\u3002SDK \u4e0d\u63d0\u4f9b\u76f4\u63a5\u5b9e\u73b0 Collection \u7684\u7c7b\uff0c\u5b9e\u73b0\u90fd\u843d\u5728 List\u3001Set \u8fd9\u4e9b\u5b50\u63a5\u53e3\u4e0a\u3002<\/p>\n

<\/p>\n

Collection<\/strong>
\u251cList<\/strong>
\u2502\u251cLinkedList<\/strong>
\u2502\u251cArrayList<\/strong>
\u2502\u2514Vector<\/strong>
\u2502\u3000\u2514Stack<\/strong>
\u2514Set<\/strong><\/p>\n

Map<\/strong>
\u251cHashtable<\/strong>
\u251cHashMap<\/strong>
\u2514WeakHashMap<\/strong><\/p>\n

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

\u4e00\u3001Collection \u63a5\u53e3<\/h2>\n

Collection \u662f\u6700\u57fa\u672c\u7684\u96c6\u5408\u63a5\u53e3\uff0c\u4ee3\u8868\u4e00\u7ec4 Object\uff0c\u4e5f\u5c31\u662f\u5143\u7d20\u3002\u6709\u7684\u5141\u8bb8\u91cd\u590d\uff0c\u6709\u7684\u4e0d\u5141\u8bb8\uff1b\u6709\u7684\u80fd\u6392\u5e8f\uff0c\u6709\u7684\u4e0d\u80fd\u3002<\/p>\n

\u6240\u6709\u5b9e\u73b0\u7c7b\u90fd\u8981\u63d0\u4f9b\u4e24\u4e2a\u6807\u51c6\u6784\u9020\uff1a\u65e0\u53c2\u6784\u9020\u521b\u5efa\u7a7a\u96c6\u5408\uff1b\u5e26\u4e00\u4e2a Collection \u53c2\u6570\u7684\u6784\u9020\uff0c\u590d\u5236\u51fa\u4e00\u4efd\u76f8\u540c\u5143\u7d20\u7684\u65b0\u96c6\u5408\u3002<\/p>\n

\u4e0d\u8bba\u5b9e\u9645\u7c7b\u578b\u662f\u4ec0\u4e48\uff0c\u90fd\u652f\u6301 iterator()<\/code>\uff0c\u8fd4\u56de\u8fed\u4ee3\u5b50\uff0c\u9010\u4e00\u8bbf\u95ee\u5143\u7d20\uff1a<\/p>\n

Iterator it = collection.iterator(); \/\/ \u83b7\u5f97\u4e00\u4e2a\u8fed\u4ee3\u5b50\n\nwhile(it.hasNext()) {\n\nObject obj = it.next(); \/\/ \u5f97\u5230\u4e0b\u4e00\u4e2a\u5143\u7d20\n\n}<\/code><\/pre>\n
\u7531 Collection \u6d3e\u751f\u7684\u4e24\u4e2a\u63a5\u53e3\u662f List<\/strong> \u548c Set<\/strong>\u3002\u4e3b\u8981\u65b9\u6cd5\uff1a<\/p>\n
boolean add(Object o)\u6dfb\u52a0\u5bf9\u8c61\u5230\u96c6\u5408\n\nboolean remove(Object o)\u5220\u9664\u6307\u5b9a\u7684\u5bf9\u8c61\n\nint size()\u8fd4\u56de\u5f53\u524d\u96c6\u5408\u4e2d\u5143\u7d20\u7684\u6570\u91cf\n\nboolean contains(Object o)\u67e5\u627e\u96c6\u5408\u4e2d\u662f\u5426\u6709\u6307\u5b9a\u7684\u5bf9\u8c61\n\nboolean isEmpty()\u5224\u65ad\u96c6\u5408\u662f\u5426\u4e3a\u7a7a\n\nIterator iterator()\u8fd4\u56de\u4e00\u4e2a\u8fed\u4ee3\u5668\n\nboolean containsAll(Collection c)\u67e5\u627e\u96c6\u5408\u4e2d\u662f\u5426\u6709\u96c6\u5408c\u4e2d\u7684\u5143\u7d20\n\nboolean addAll(Collection c)\u5c06\u96c6\u5408c\u4e2d\u6240\u6709\u7684\u5143\u7d20\u6dfb\u52a0\u7ed9\u8be5\u96c6\u5408\n\nvoid clear()\u5220\u9664\u96c6\u5408\u4e2d\u6240\u6709\u5143\u7d20\n\nvoid removeAll(Collection c)\u4ece\u96c6\u5408\u4e2d\u5220\u9664c\u96c6\u5408\u4e2d\u4e5f\u6709\u7684\u5143\u7d20\n\nvoid retainAll(Collection c)\u4ece\u96c6\u5408\u4e2d\u5220\u9664\u96c6\u5408c\u4e2d\u4e0d\u5305\u542b\u7684\u5143\u7d20<\/code><\/pre>\n
\u4e8c\u3001List \u63a5\u53e3<\/h2>\n
List \u662f\u6709\u5e8f Collection\uff0c\u80fd\u7cbe\u786e\u63a7\u5236\u6bcf\u4e2a\u5143\u7d20\u7684\u63d2\u5165\u4f4d\u7f6e\uff0c\u53ef\u7528\u7d22\u5f15\uff08\u7c7b\u4f3c\u6570\u7ec4\u4e0b\u6807\uff09\u8bbf\u95ee\uff0c\u5e76\u5141\u8bb8\u91cd\u590d\u5143\u7d20\u3002<\/p>\n
\u9664\u4e86 iterator()<\/code>\uff0cList \u8fd8\u63d0\u4f9b listIterator()<\/code>\u3002ListIterator \u6bd4\u6807\u51c6 Iterator \u591a\u4e86 add\u3001\u5220\u9664\u3001\u8bbe\u5b9a\uff0c\u4ee5\u53ca\u5411\u524d\/\u5411\u540e\u904d\u5386\u3002<\/p>\n
\u5e38\u7528\u5b9e\u73b0\uff1aLinkedList<\/code>\u3001ArrayList<\/code>\u3001Vector<\/code>\u3001Stack<\/code>\u3002\u4e3b\u8981\u65b9\u6cd5\uff1a<\/p>\n
void add(int index,Object element)\u5728\u6307\u5b9a\u4f4d\u7f6e\u4e0a\u6dfb\u52a0\u4e00\u4e2a\u5bf9\u8c61\n\nboolean addAll(int index,Collection c)\u5c06\u96c6\u5408c\u7684\u5143\u7d20\u6dfb\u52a0\u5230\u6307\u5b9a\u7684\u4f4d\u7f6e\n\nObject get(int index)\u8fd4\u56deList\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\n\nint indexOf(Object o)\u8fd4\u56de\u7b2c\u4e00\u4e2a\u51fa\u73b0\u5143\u7d20o\u7684\u4f4d\u7f6e.\n\nObject removeint(int index)\u5220\u9664\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\n\nObject set(int index,Object element)\u7528\u5143\u7d20element\u53d6\u4ee3\u4f4d\u7f6eindex\u4e0a\u7684\u5143\u7d20,\u8fd4\u56de\u88ab\u53d6\u4ee3\u7684\u5143\u7d20<\/code><\/pre>\n
LinkedList<\/h3>\n
\u5141\u8bb8 null\u3002\u989d\u5916\u63d0\u4f9b\u5728\u9996\u5c3e get\u3001remove\u3001insert \u7684\u65b9\u6cd5\uff0c\u56e0\u6b64\u53ef\u5f53\u5806\u6808\u3001\u961f\u5217\u6216\u53cc\u7aef\u961f\u5217\u3002\u6ca1\u6709\u540c\u6b65\u65b9\u6cd5\u3002\u591a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\u5fc5\u987b\u81ea\u5df1\u540c\u6b65\uff0c\u4f8b\u5982\uff1a<\/p>\n
List list = Collections.synchronizedList(new LinkedList(...));<\/code><\/p>\n
ArrayList<\/h3>\n
\u53ef\u53d8\u5927\u5c0f\u6570\u7ec4\uff0c\u5141\u8bb8\u6240\u6709\u5143\u7d20\uff08\u542b null\uff09\uff0c\u4e0d\u540c\u6b65\u3002size<\/code>\u3001isEmpty<\/code>\u3001get<\/code>\u3001set<\/code> \u662f\u5e38\u6570\u65f6\u95f4\uff1badd<\/code> \u662f\u644a\u8fd8\u5e38\u6570\uff0c\u52a0 n \u4e2a\u5143\u7d20\u8981 O(n)\uff1b\u5176\u4f59\u591a\u4e3a\u7ebf\u6027\u3002<\/p>\n
\u6bcf\u4e2a\u5b9e\u4f8b\u6709\u5bb9\u91cf\uff08\u5e95\u5c42\u6570\u7ec4\u5927\u5c0f\uff09\uff0c\u52a0\u5143\u7d20\u65f6\u81ea\u52a8\u589e\u957f\uff0c\u589e\u957f\u7b97\u6cd5\u672a\u89c4\u5b9a\u3002\u63d2\u5165\u5927\u91cf\u5143\u7d20\u524d\u53ef\u8c03 ensureCapacity<\/code> \u63d0\u524d\u6269\u5bb9\u3002\u548c LinkedList \u4e00\u6837\u975e\u540c\u6b65\u3002\u4e3b\u8981\u65b9\u6cd5\uff1a<\/p>\n
Boolean add(Object o)\u5c06\u6307\u5b9a\u5143\u7d20\u6dfb\u52a0\u5230\u5217\u8868\u7684\u672b\u5c3e\n\nBoolean add(int index,Object element)\u5728\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u52a0\u5165\u6307\u5b9a\u5143\u7d20\n\nBoolean addAll(Collection c)\u5c06\u6307\u5b9a\u96c6\u5408\u6dfb\u52a0\u5230\u5217\u8868\u672b\u5c3e\n\nBoolean addAll(int index,Collection c)\u5728\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u52a0\u5165\u6307\u5b9a\u96c6\u5408\n\nBoolean clear()\u5220\u9664\u5217\u8868\u4e2d\u6240\u6709\u5143\u7d20\n\nBoolean clone()\u8fd4\u56de\u8be5\u5217\u8868\u5b9e\u4f8b\u7684\u4e00\u4e2a\u62f7\u8d1d\n\nBoolean contains(Object o)\u5224\u65ad\u5217\u8868\u4e2d\u662f\u5426\u5305\u542b\u5143\u7d20\n\nBoolean ensureCapacity(int m)\u589e\u52a0\u5217\u8868\u7684\u5bb9\u91cf,\u5982\u679c\u5fc5\u987b,\u8be5\u5217\u8868\u80fd\u591f\u5bb9\u7eb3m\u4e2a\u5143\u7d20\n\nObject get(int index)\u8fd4\u56de\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20\n\nInt indexOf(Object elem)\u5728\u5217\u8868\u4e2d\u67e5\u627e\u6307\u5b9a\u5143\u7d20\u7684\u4e0b\u6807\n\nInt size()\u8fd4\u56de\u5f53\u524d\u5217\u8868\u7684\u5143\u7d20\u4e2a\u6570<\/code><\/pre>\n
Vector \u4e0e Stack<\/h3>\n
Vector \u5f88\u50cf ArrayList\uff0c\u4f46\u662f\u540c\u6b65<\/strong>\u7684\u3002Iterator \u63a5\u53e3\u76f8\u540c\uff0c\u4f46 Vector \u88ab\u53e6\u4e00\u7ebf\u7a0b\u6539\u8fc7\u72b6\u6001\u540e\uff0c\u518d\u8c03 Iterator \u4f1a\u629b ConcurrentModificationException<\/code>\uff0c\u5fc5\u987b\u6355\u83b7\u3002<\/p>\n
Stack \u7ee7\u627f Vector\uff0c\u540e\u8fdb\u5148\u51fa\u3002\u989d\u5916\u4e94\u4e2a\u65b9\u6cd5\uff1apush<\/code> \/ pop<\/code>\uff0cpeek<\/code> \u770b\u6808\u9876\uff0cempty<\/code> \u6d4b\u7a7a\uff0csearch<\/code> \u67e5\u4f4d\u7f6e\u3002\u521a\u521b\u5efa\u65f6\u662f\u7a7a\u6808\u3002<\/p>\n
\u4e09\u3001Set \u63a5\u53e3<\/h2>\n
Set \u4e0d\u542b\u91cd\u590d\u5143\u7d20\uff1a\u4efb\u610f e1\u3001e2 \u90fd\u6709 e1.equals(e2)==false<\/code>\uff0c\u6700\u591a\u4e00\u4e2a null\u3002\u6784\u9020\u65f6\u4f20\u5165\u7684 Collection \u4e5f\u4e0d\u80fd\u5e26\u91cd\u590d\u5143\u7d20\u3002<\/p>\n
\u53ef\u53d8\u5bf9\u8c61\u8981\u5c0f\u5fc3\uff1a\u82e5 Set \u91cc\u67d0\u4e2a\u5143\u7d20\u6539\u4e86\u81ea\u8eab\u72b6\u6001\uff0c\u5bfc\u81f4 equals<\/code> \u53d8\u6210 true\uff0c\u96c6\u5408\u5951\u7ea6\u5c31\u4f1a\u88ab\u7834\u574f\u3002<\/p>\n
\u56db\u3001Map \u63a5\u53e3<\/h2>\n
Map \u6ca1\u6709<\/strong>\u7ee7\u627f Collection\u3002\u5b83\u63d0\u4f9b key \u5230 value \u7684\u6620\u5c04\uff1a\u4e0d\u80fd\u6709\u76f8\u540c key\uff0c\u6bcf\u4e2a key \u53ea\u6620\u5c04\u4e00\u4e2a value\u3002\u4e09\u79cd\u89c6\u56fe\uff1a\u4e00\u7ec4 key\u3001\u4e00\u7ec4 value\u3001\u4e00\u7ec4 key-value \u6620\u5c04\u3002\u4e3b\u8981\u65b9\u6cd5\uff1a<\/p>\n
boolean equals(Object o)\u6bd4\u8f83\u5bf9\u8c61\n\nboolean remove(Object o)\u5220\u9664\u4e00\u4e2a\u5bf9\u8c61\n\nput(Object key,Object value)\u6dfb\u52a0key\u548cvalue<\/code><\/pre>\n
Hashtable<\/h3>\n
\u5b9e\u73b0 key-value \u54c8\u5e0c\u8868\uff0ckey\u3001value \u90fd\u4e0d\u80fd\u662f null\u3002put<\/code> \/ get<\/code> \u57fa\u672c\u662f\u5e38\u6570\u65f6\u95f4\u3002\u7528 initial capacity \u548c load factor \u8c03\u6027\u80fd\uff0c\u9ed8\u8ba4\u8d1f\u8f7d\u56e0\u5b50 0.75 \u8f83\u5747\u8861\uff1b\u589e\u5927\u53ef\u7701\u7a7a\u95f4\u4f46\u67e5\u627e\u53d8\u6162\u3002<\/p>\n
\u628a 1\u30012\u30013 \u653e\u8fdb\u53bb\uff0ckey \u5206\u522b\u662f one\u3001two\u3001three\uff1a<\/p>\n
Hashtable numbers = new Hashtable();\n\nnumbers.put(\u201cone\u201d, new Integer(1));\n\nnumbers.put(\u201ctwo\u201d, new Integer(2));\n\nnumbers.put(\u201cthree\u201d, new Integer(3));<\/code><\/pre>\n
\u6309 key \u53d6\u51fa 2\uff1a<\/p>\n
Integer n = (Integer)numbers.get(\u201ctwo\u201d);\n\nSystem.out.println(\u201ctwo = \u201d + n);<\/code><\/pre>\n
\u4f5c\u4e3a key \u7684\u5bf9\u8c61\u5fc5\u987b\u5b9e\u73b0 hashCode<\/code> \u548c equals<\/code>\u3002\u4e24\u5bf9\u8c61 equals<\/code> \u4e3a true \u5219 hashCode \u5fc5\u987b\u76f8\u540c\uff1b\u4e0d\u540c\u5bf9\u8c61 hashCode \u53ef\u4ee5\u76f8\u540c\uff08\u51b2\u7a81\uff09\uff0c\u51b2\u7a81\u4f1a\u52a0\u5927\u5f00\u9500\u3002\u82e5\u76f8\u540c\u5bf9\u8c61\u5374\u6709\u4e0d\u540c hashCode\uff0cget<\/code> \u4f1a\u62ff\u5230 null\u3002\u53ea\u8bb0\u4e00\u6761\uff1aequals \u548c hashCode \u8981\u4e00\u8d77\u8986\u5199<\/strong>\u3002Hashtable \u662f\u540c\u6b65\u7684\u3002<\/p>\n
HashMap \u4e0e WeakHashMap<\/h3>\n
HashMap \u7c7b\u4f3c Hashtable\uff0c\u4f46\u975e\u540c\u6b65<\/strong>\uff0c\u4e14\u5141\u8bb8 null key \u548c null value\u3002\u5f53\u628a\u5b83\u5f53 Collection \u770b\uff08values()<\/code>\uff09\u65f6\uff0c\u8fed\u4ee3\u5f00\u9500\u548c\u5bb9\u91cf\u6210\u6b63\u6bd4\uff1a\u8fed\u4ee3\u5f88\u91cd\u8981\u65f6\uff0c\u522b\u628a\u521d\u59cb\u5bb9\u91cf\u8bbe\u592a\u9ad8\uff0c\u4e5f\u522b\u628a load factor \u8bbe\u592a\u4f4e\u3002<\/p>\n
WeakHashMap \u662f\u6539\u8fdb\u7684 HashMap\uff0c\u5bf9 key \u4f7f\u7528\u5f31\u5f15\u7528\uff1a\u5916\u90e8\u4e0d\u518d\u5f15\u7528\u8be5 key \u65f6\uff0cGC \u53ef\u4ee5\u56de\u6536\u5b83\u3002<\/p>\n
\u4e94\u3001\u600e\u4e48\u9009<\/h2>\n\n\n\n\n\n\n\n\n\n\n
\u9700\u6c42<\/th>\n\u4f18\u5148<\/th>\n<\/tr>\n<\/thead>\n
\u6808\u3001\u961f\u5217<\/td>\nList\uff08LinkedList \u53ef\u5f53 deque\uff09<\/td>\n<\/tr>\n
\u9891\u7e41\u63d2\u5165\/\u5220\u9664<\/td>\nLinkedList<\/td>\n<\/tr>\n
\u6309\u7d22\u5f15\u968f\u673a\u8bbf\u95ee<\/td>\nArrayList<\/td>\n<\/tr>\n
\u5355\u7ebf\u7a0b\u3001\u8981\u5feb<\/td>\n\u975e\u540c\u6b65\u7c7b\uff08ArrayList \/ HashMap\uff09<\/td>\n<\/tr>\n
\u591a\u7ebf\u7a0b\u540c\u65f6\u6539<\/td>\n\u540c\u6b65\u7c7b\uff08Vector \/ Hashtable\uff09\u6216\u5305\u88c5\u540e\u518d\u7528<\/td>\n<\/tr>\n
\u81ea\u5b9a\u4e49\u5bf9\u8c61\u505a Map \u7684 key<\/td>\n\u540c\u65f6\u8986\u5199 equals \u4e0e hashCode<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\u5c3d\u91cf\u8fd4\u56de\u63a5\u53e3\u800c\u4e0d\u662f\u5b9e\u73b0\u7c7b\uff0c\u4f8b\u5982\u8fd4\u56de List \u800c\u4e0d\u662f ArrayList\uff0c\u4ee5\u540e\u6362\u6210 LinkedList \u65f6\u8c03\u7528\u65b9\u4e0d\u7528\u6539\u2014\u2014\u8fd9\u5c31\u662f\u9488\u5bf9\u62bd\u8c61\u7f16\u7a0b\u3002<\/p>\n
\n
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