{"id":169,"date":"2015-04-12T15:41:20","date_gmt":"2015-04-12T07:41:20","guid":{"rendered":"https:\/\/ai.zhousir.top\/?p=169"},"modified":"2016-04-18T09:00:42","modified_gmt":"2016-04-18T01:00:42","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":"

\u7ebf\u6027\u8868\uff0c\u94fe\u8868\uff0c\u54c8\u5e0c\u8868\u662f\u5e38\u7528\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5728\u8fdb\u884cJava\u5f00\u53d1\u65f6\uff0cJDK\u5df2\u7ecf\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u7cfb\u5217\u76f8\u5e94\u7684\u7c7b\u6765\u5b9e\u73b0\u57fa\u672c\u7684\u6570\u636e\u7ed3\u6784<\/strong>\u3002\u8fd9\u4e9b\u7c7b\u5747\u5728java.util\u5305\u4e2d\u3002\u672c\u6587\u8bd5\u56fe\u901a\u8fc7\u7b80\u5355\u7684\u63cf\u8ff0\uff0c\u5411\u8bfb\u8005\u9610\u8ff0\u5404\u4e2a\u7c7b\u7684\u4f5c\u7528\u4ee5\u53ca\u5982\u4f55\u6b63\u786e\u4f7f\u7528\u8fd9\u4e9b\u7c7b\u3002
\n<\/p>\n

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

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

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

Collection\u63a5\u53e3<\/h3>\n

Collection\u662f\u6700\u57fa\u672c\u7684\u96c6\u5408\u63a5\u53e3\uff0c\u4e00\u4e2aCollection\u4ee3\u8868\u4e00\u7ec4Object\uff0c\u5373Collection\u7684\u5143\u7d20\uff08Elements\uff09\u3002\u4e00\u4e9bCollection\u5141\u8bb8\u76f8\u540c\u7684\u5143
\n\u7d20\u800c\u53e6\u4e00\u4e9b\u4e0d\u884c\u3002\u4e00\u4e9b\u80fd\u6392\u5e8f\u800c\u53e6\u4e00\u4e9b\u4e0d\u884c\u3002Java SDK\u4e0d\u63d0\u4f9b\u76f4\u63a5\u7ee7\u627f\u81eaCollection\u7684\u7c7b\uff0cJava SDK\u63d0\u4f9b\u7684\u7c7b\u90fd\u662f\u7ee7\u627f\u81eaCollection\u7684\u201c\u5b50
\n\u63a5\u53e3\u201d\u5982List\u548cSet\u3002
\n\u6240\u6709\u5b9e\u73b0Collection\u63a5\u53e3\u7684\u7c7b\u90fd\u5fc5\u987b\u63d0\u4f9b\u4e24\u4e2a\u6807\u51c6\u7684\u6784\u9020\u51fd\u6570\uff1a\u65e0\u53c2\u6570\u7684\u6784\u9020\u51fd\u6570\u7528\u4e8e\u521b\u5efa\u4e00\u4e2a\u7a7a\u7684Collection\uff0c\u6709\u4e00\u4e2aCollection\u53c2
\n\u6570\u7684\u6784\u9020\u51fd\u6570\u7528\u4e8e\u521b\u5efa\u4e00\u4e2a\u65b0\u7684Collection\uff0c\u8fd9\u4e2a\u65b0\u7684Collection\u4e0e\u4f20\u5165\u7684Collection\u6709\u76f8\u540c\u7684\u5143\u7d20\u3002\u540e\u4e00\u4e2a\u6784\u9020\u51fd\u6570\u5141\u8bb8\u7528\u6237\u590d\u5236\u4e00\u4e2a
\nCollection\u3002
\n\u5982\u4f55\u904d\u5386Collection\u4e2d\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20\uff1f\u4e0d\u8bbaCollection\u7684\u5b9e\u9645\u7c7b\u578b\u5982\u4f55\uff0c\u5b83\u90fd\u652f\u6301\u4e00\u4e2aiterator()\u7684\u65b9\u6cd5\uff0c\u8be5\u65b9\u6cd5\u8fd4\u56de\u4e00\u4e2a\u8fed\u4ee3\u5b50\uff0c\u4f7f
\n\u7528\u8be5\u8fed\u4ee3\u5b50\u5373\u53ef\u9010\u4e00\u8bbf\u95eeCollection\u4e2d\u6bcf\u4e00\u4e2a\u5143\u7d20\u3002\u5178\u578b\u7684\u7528\u6cd5\u5982\u4e0b\uff1a<\/p>\n

[java]Iterator it = collection.iterator(); \/\/ \u83b7\u5f97\u4e00\u4e2a\u8fed\u4ee3\u5b50
\nwhile(it.hasNext()) {
\nObject obj = it.next(); \/\/ \u5f97\u5230\u4e0b\u4e00\u4e2a\u5143\u7d20
\n}[\/java]<\/p>\n

\u7531Collection\u63a5\u53e3\u6d3e\u751f\u7684\u4e24\u4e2a\u63a5\u53e3\u662fList\u548cSet\u3002<\/strong>
\n\u4e3b\u8981\u65b9\u6cd5:<\/p>\n

[java]boolean add(Object o)\u6dfb\u52a0\u5bf9\u8c61\u5230\u96c6\u5408
\nboolean remove(Object o)\u5220\u9664\u6307\u5b9a\u7684\u5bf9\u8c61
\nint size()\u8fd4\u56de\u5f53\u524d\u96c6\u5408\u4e2d\u5143\u7d20\u7684\u6570\u91cf
\nboolean contains(Object o)\u67e5\u627e\u96c6\u5408\u4e2d\u662f\u5426\u6709\u6307\u5b9a\u7684\u5bf9\u8c61
\nboolean isEmpty()\u5224\u65ad\u96c6\u5408\u662f\u5426\u4e3a\u7a7a
\nIterator iterator()\u8fd4\u56de\u4e00\u4e2a\u8fed\u4ee3\u5668
\nboolean containsAll(Collection c)\u67e5\u627e\u96c6\u5408\u4e2d\u662f\u5426\u6709\u96c6\u5408c\u4e2d\u7684\u5143\u7d20
\nboolean addAll(Collection c)\u5c06\u96c6\u5408c\u4e2d\u6240\u6709\u7684\u5143\u7d20\u6dfb\u52a0\u7ed9\u8be5\u96c6\u5408
\nvoid clear()\u5220\u9664\u96c6\u5408\u4e2d\u6240\u6709\u5143\u7d20
\nvoid removeAll(Collection c)\u4ece\u96c6\u5408\u4e2d\u5220\u9664c\u96c6\u5408\u4e2d\u4e5f\u6709\u7684\u5143\u7d20
\nvoid retainAll(Collection c)\u4ece\u96c6\u5408\u4e2d\u5220\u9664\u96c6\u5408c\u4e2d\u4e0d\u5305\u542b\u7684\u5143\u7d20[\/java]<\/p>\n

List\u63a5\u53e3<\/h3>\n

List\u662f\u6709\u5e8f\u7684Collection\uff0c\u4f7f\u7528\u6b64\u63a5\u53e3\u80fd\u591f\u7cbe\u786e\u7684\u63a7\u5236\u6bcf\u4e2a\u5143\u7d20\u63d2\u5165\u7684\u4f4d\u7f6e\u3002\u7528\u6237\u80fd\u591f\u4f7f\u7528\u7d22\u5f15\uff08\u5143\u7d20\u5728List\u4e2d\u7684\u4f4d\u7f6e\uff0c\u7c7b\u4f3c\u4e8e\u6570\u7ec4\u4e0b\u6807
\n\uff09\u6765\u8bbf\u95eeList\u4e2d\u7684\u5143\u7d20\uff0c\u8fd9\u7c7b\u4f3c\u4e8eJava\u7684\u6570\u7ec4\u3002\u548c\u4e0b\u9762\u8981\u63d0\u5230\u7684Set\u4e0d\u540c\uff0cList\u5141\u8bb8\u6709\u76f8\u540c\u7684\u5143\u7d20\u3002
\n\u9664\u4e86\u5177\u6709Collection\u63a5\u53e3\u5fc5\u5907\u7684iterator()\u65b9\u6cd5\u5916\uff0cList\u8fd8\u63d0\u4f9b\u4e00\u4e2alistIterator()\u65b9\u6cd5\uff0c\u8fd4\u56de\u4e00\u4e2aListIterator\u63a5\u53e3\uff0c\u548c\u6807\u51c6\u7684
\nIterator\u63a5\u53e3\u76f8\u6bd4\uff0cListIterator\u591a\u4e86\u4e00\u4e9badd()\u4e4b\u7c7b\u7684\u65b9\u6cd5\uff0c\u5141\u8bb8\u6dfb\u52a0\uff0c\u5220\u9664\uff0c\u8bbe\u5b9a\u5143\u7d20\uff0c\u8fd8\u80fd\u5411\u524d\u6216\u5411\u540e\u904d\u5386\u3002
\n\u5b9e\u73b0List\u63a5\u53e3\u7684\u5e38\u7528\u7c7b\u6709LinkedList\uff0cArrayList\uff0cVector\u548cStack\u3002
\n\u4e3b\u8981\u65b9\u6cd5:<\/p>\n

[java]void add(int index,Object element)\u5728\u6307\u5b9a\u4f4d\u7f6e\u4e0a\u6dfb\u52a0\u4e00\u4e2a\u5bf9\u8c61
\nboolean addAll(int index,Collection c)\u5c06\u96c6\u5408c\u7684\u5143\u7d20\u6dfb\u52a0\u5230\u6307\u5b9a\u7684\u4f4d\u7f6e
\nObject get(int index)\u8fd4\u56deList\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20
\nint indexOf(Object o)\u8fd4\u56de\u7b2c\u4e00\u4e2a\u51fa\u73b0\u5143\u7d20o\u7684\u4f4d\u7f6e.
\nObject removeint(int index)\u5220\u9664\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20
\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[\/java]<\/p>\n

LinkedList\u7c7b<\/strong>
\nLinkedList\u5b9e\u73b0\u4e86List\u63a5\u53e3\uff0c\u5141\u8bb8null\u5143\u7d20\u3002\u6b64\u5916LinkedList\u63d0\u4f9b\u989d\u5916\u7684get\uff0cremove\uff0cinsert\u65b9\u6cd5\u5728LinkedList\u7684\u9996\u90e8\u6216\u5c3e\u90e8
\n\u3002\u8fd9\u4e9b\u64cd\u4f5c\u4f7fLinkedList\u53ef\u88ab\u7528\u4f5c\u5806\u6808\uff08stack\uff09\uff0c\u961f\u5217\uff08queue\uff09\u6216\u53cc\u5411\u961f\u5217\uff08deque\uff09\u3002
\n\u6ce8\u610fLinkedList\u6ca1\u6709\u540c\u6b65\u65b9\u6cd5\u3002\u5982\u679c\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u8bbf\u95ee\u4e00\u4e2aList\uff0c\u5219\u5fc5\u987b\u81ea\u5df1\u5b9e\u73b0\u8bbf\u95ee\u540c\u6b65\u3002\u4e00\u79cd\u89e3\u51b3\u65b9\u6cd5\u662f\u5728\u521b\u5efaList\u65f6\u6784\u9020\u4e00
\n\u4e2a\u540c\u6b65\u7684List\uff1a
\nList list = Collections.synchronizedList(new LinkedList(…));<\/p>\n

ArrayList\u7c7b<\/strong>
\nArrayList\u5b9e\u73b0\u4e86\u53ef\u53d8\u5927\u5c0f\u7684\u6570\u7ec4\u3002\u5b83\u5141\u8bb8\u6240\u6709\u5143\u7d20\uff0c\u5305\u62ecnull\u3002ArrayList\u6ca1\u6709\u540c\u6b65\u3002
\nsize\uff0cisEmpty\uff0cget\uff0cset\u65b9\u6cd5\u8fd0\u884c\u65f6\u95f4\u4e3a\u5e38\u6570\u3002\u4f46\u662fadd\u65b9\u6cd5\u5f00\u9500\u4e3a\u5206\u644a\u7684\u5e38\u6570\uff0c\u6dfb\u52a0n\u4e2a\u5143\u7d20\u9700\u8981O(n)\u7684\u65f6\u95f4\u3002\u5176\u4ed6\u7684\u65b9\u6cd5\u8fd0\u884c\u65f6\u95f4
\n\u4e3a\u7ebf\u6027
\n\u3002
\n\u6bcf\u4e2aArrayList\u5b9e\u4f8b\u90fd\u6709\u4e00\u4e2a\u5bb9\u91cf\uff08Capacity\uff09\uff0c\u5373\u7528\u4e8e\u5b58\u50a8\u5143\u7d20\u7684\u6570\u7ec4\u7684\u5927\u5c0f\u3002\u8fd9\u4e2a\u5bb9\u91cf\u53ef\u968f\u7740\u4e0d\u65ad\u6dfb\u52a0\u65b0\u5143\u7d20\u800c\u81ea\u52a8\u589e\u52a0\uff0c\u4f46\u662f
\n\u589e\u957f
\n\u7b97\u6cd5\u5e76\u6ca1\u6709\u5b9a\u4e49\u3002\u5f53\u9700\u8981\u63d2\u5165\u5927\u91cf\u5143\u7d20\u65f6\uff0c\u5728\u63d2\u5165\u524d\u53ef\u4ee5\u8c03\u7528ensureCapacity\u65b9\u6cd5\u6765\u589e\u52a0ArrayList\u7684\u5bb9\u91cf\u4ee5\u63d0\u9ad8\u63d2\u5165\u6548\u7387\u3002
\n\u548cLinkedList\u4e00\u6837\uff0cArrayList\u4e5f\u662f\u975e\u540c\u6b65\u7684\uff08unsynchronized\uff09\u3002
\n\u4e3b\u8981\u65b9\u6cd5:<\/p>\n

[java]Boolean add(Object o)\u5c06\u6307\u5b9a\u5143\u7d20\u6dfb\u52a0\u5230\u5217\u8868\u7684\u672b\u5c3e
\nBoolean add(int index,Object element)\u5728\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u52a0\u5165\u6307\u5b9a\u5143\u7d20
\nBoolean addAll(Collection c)\u5c06\u6307\u5b9a\u96c6\u5408\u6dfb\u52a0\u5230\u5217\u8868\u672b\u5c3e
\nBoolean addAll(int index,Collection c)\u5728\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u52a0\u5165\u6307\u5b9a\u96c6\u5408
\nBoolean clear()\u5220\u9664\u5217\u8868\u4e2d\u6240\u6709\u5143\u7d20
\nBoolean clone()\u8fd4\u56de\u8be5\u5217\u8868\u5b9e\u4f8b\u7684\u4e00\u4e2a\u62f7\u8d1d
\nBoolean contains(Object o)\u5224\u65ad\u5217\u8868\u4e2d\u662f\u5426\u5305\u542b\u5143\u7d20
\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
\nObject get(int index)\u8fd4\u56de\u5217\u8868\u4e2d\u6307\u5b9a\u4f4d\u7f6e\u7684\u5143\u7d20
\nInt indexOf(Object elem)\u5728\u5217\u8868\u4e2d\u67e5\u627e\u6307\u5b9a\u5143\u7d20\u7684\u4e0b\u6807
\nInt size()\u8fd4\u56de\u5f53\u524d\u5217\u8868\u7684\u5143\u7d20\u4e2a\u6570[\/java]<\/p>\n

Vector\u7c7b<\/strong>
\nVector\u975e\u5e38\u7c7b\u4f3cArrayList\uff0c\u4f46\u662fVector\u662f\u540c\u6b65\u7684\u3002\u7531Vector\u521b\u5efa\u7684Iterator\uff0c\u867d\u7136\u548cArrayList\u521b\u5efa\u7684Iterator\u662f\u540c\u4e00\u63a5\u53e3\uff0c\u4f46\u662f\uff0c
\n\u56e0\u4e3aVector\u662f\u540c\u6b65\u7684\uff0c\u5f53\u4e00\u4e2aIterator\u88ab\u521b\u5efa\u800c\u4e14\u6b63\u5728\u88ab\u4f7f\u7528\uff0c\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u6539\u53d8\u4e86Vector\u7684\u72b6\u6001\uff08\u4f8b\u5982\uff0c\u6dfb\u52a0\u6216\u5220\u9664\u4e86\u4e00\u4e9b\u5143\u7d20\uff09\uff0c\u8fd9
\n\u65f6\u8c03\u7528Iterator\u7684\u65b9\u6cd5\u65f6\u5c06\u629b\u51faConcurrentModificationException\uff0c\u56e0\u6b64\u5fc5\u987b\u6355\u83b7\u8be5\u5f02\u5e38\u3002<\/p>\n

Stack \u7c7b<\/strong>
\nStack\u7ee7\u627f\u81eaVector\uff0c\u5b9e\u73b0\u4e00\u4e2a\u540e\u8fdb\u5148\u51fa\u7684\u5806\u6808\u3002Stack\u63d0\u4f9b5\u4e2a\u989d\u5916\u7684\u65b9\u6cd5\u4f7f\u5f97Vector\u5f97\u4ee5\u88ab\u5f53\u4f5c\u5806\u6808\u4f7f\u7528\u3002\u57fa\u672c\u7684push\u548cpop\u65b9\u6cd5\uff0c
\n\u8fd8\u6709peek\u65b9\u6cd5\u5f97\u5230\u6808\u9876\u7684\u5143\u7d20\uff0cempty\u65b9\u6cd5\u6d4b\u8bd5\u5806\u6808\u662f\u5426\u4e3a\u7a7a\uff0csearch\u65b9\u6cd5\u68c0\u6d4b\u4e00\u4e2a\u5143\u7d20\u5728\u5806\u6808\u4e2d\u7684\u4f4d\u7f6e\u3002Stack\u521a\u521b\u5efa\u540e\u662f\u7a7a\u6808\u3002<\/p>\n

Set\u63a5\u53e3<\/h3>\n

Set\u662f\u4e00\u79cd\u4e0d\u5305\u542b\u91cd\u590d\u7684\u5143\u7d20\u7684Collection\uff0c\u5373\u4efb\u610f\u7684\u4e24\u4e2a\u5143\u7d20e1\u548ce2\u90fd\u6709e1.equals(e2)=false\uff0cSet\u6700\u591a\u6709\u4e00\u4e2anull\u5143\u7d20\u3002
\n\u5f88\u660e\u663e\uff0cSet\u7684\u6784\u9020\u51fd\u6570\u6709\u4e00\u4e2a\u7ea6\u675f\u6761\u4ef6\uff0c\u4f20\u5165\u7684Collection\u53c2\u6570\u4e0d\u80fd\u5305\u542b\u91cd\u590d\u7684\u5143\u7d20\u3002
\n\u8bf7\u6ce8\u610f\uff1a\u5fc5\u987b\u5c0f\u5fc3\u64cd\u4f5c\u53ef\u53d8\u5bf9\u8c61\uff08Mutable Object\uff09\u3002\u5982\u679c\u4e00\u4e2aSet\u4e2d\u7684\u53ef\u53d8\u5143\u7d20\u6539\u53d8\u4e86\u81ea\u8eab\u72b6\u6001\u5bfc\u81f4Object.equals(Object)=true\u5c06
\n\u5bfc\u81f4\u4e00\u4e9b\u95ee\u9898\u3002<\/p>\n

Map\u63a5\u53e3<\/h3>\n

\u8bf7\u6ce8\u610f\uff0cMap\u6ca1\u6709\u7ee7\u627fCollection\u63a5\u53e3\uff0cMap\u63d0\u4f9bkey\u5230value\u7684\u6620\u5c04\u3002\u4e00\u4e2aMap\u4e2d\u4e0d\u80fd\u5305\u542b\u76f8\u540c\u7684key\uff0c\u6bcf\u4e2akey\u53ea\u80fd\u6620\u5c04\u4e00\u4e2avalue\u3002
\nMap\u63a5\u53e3\u63d0\u4f9b3\u79cd\u96c6\u5408\u7684\u89c6\u56fe\uff0cMap\u7684\u5185\u5bb9\u53ef\u4ee5\u88ab\u5f53\u4f5c\u4e00\u7ec4key\u96c6\u5408\uff0c\u4e00\u7ec4value\u96c6\u5408\uff0c\u6216\u8005\u4e00\u7ec4key-value\u6620\u5c04\u3002
\n\u4e3b\u8981\u65b9\u6cd5:<\/p>\n

[java]boolean equals(Object o)\u6bd4\u8f83\u5bf9\u8c61
\nboolean remove(Object o)\u5220\u9664\u4e00\u4e2a\u5bf9\u8c61
\nput(Object key,Object value)\u6dfb\u52a0key\u548cvalue[\/java]<\/p>\n

Hashtable\u7c7b<\/strong>
\nHashtable\u7ee7\u627fMap\u63a5\u53e3\uff0c\u5b9e\u73b0\u4e00\u4e2akey-value\u6620\u5c04\u7684\u54c8\u5e0c\u8868\u3002\u4efb\u4f55\u975e\u7a7a\uff08non-null\uff09\u7684\u5bf9\u8c61\u90fd\u53ef\u4f5c\u4e3akey\u6216\u8005value\u3002
\n\u6dfb\u52a0\u6570\u636e\u4f7f\u7528put(key, value)\uff0c\u53d6\u51fa\u6570\u636e\u4f7f\u7528get(key)\uff0c\u8fd9\u4e24\u4e2a\u57fa\u672c\u64cd\u4f5c\u7684\u65f6\u95f4\u5f00\u9500\u4e3a\u5e38\u6570\u3002
\nHashtable\u901a\u8fc7initial capacity\u548cload factor\u4e24\u4e2a\u53c2\u6570\u8c03\u6574\u6027\u80fd\u3002\u901a\u5e38\u7f3a\u7701\u7684load factor 0.75\u8f83\u597d\u5730\u5b9e\u73b0\u4e86\u65f6\u95f4\u548c\u7a7a\u95f4\u7684\u5747\u8861\u3002\u589e\u5927
\nload factor\u53ef\u4ee5\u8282\u7701\u7a7a\u95f4\u4f46\u76f8\u5e94\u7684\u67e5\u627e\u65f6\u95f4\u5c06\u589e\u5927\uff0c\u8fd9\u4f1a\u5f71\u54cd\u50cfget\u548cput\u8fd9\u6837\u7684\u64cd\u4f5c\u3002
\n\u4f7f\u7528Hashtable\u7684\u7b80\u5355\u793a\u4f8b\u5982\u4e0b\uff0c\u5c061\uff0c2\uff0c3\u653e\u5230Hashtable\u4e2d\uff0c\u4ed6\u4eec\u7684key\u5206\u522b\u662f\u201done\u201d\uff0c\u201dtwo\u201d\uff0c \u201dthree\u201d\uff1a<\/p>\n

[java]Hashtable numbers = new Hashtable();
\nnumbers.put(\u201cone\u201d, new Integer(1));
\nnumbers.put(\u201ctwo\u201d, new Integer(2));
\nnumbers.put(\u201cthree\u201d, new Integer(3));[\/java]<\/p>\n

\u8981\u53d6\u51fa\u4e00\u4e2a\u6570\uff0c\u6bd4\u59822\uff0c\u7528\u76f8\u5e94\u7684key\uff1a<\/p>\n

[java]Integer n = (Integer)numbers.get(\u201ctwo\u201d);
\nSystem.out.println(\u201ctwo = \u201d + n);[\/java]<\/p>\n

\u7531\u4e8e\u4f5c\u4e3akey\u7684\u5bf9\u8c61\u5c06\u901a\u8fc7\u8ba1\u7b97\u5176\u6563\u5217\u51fd\u6570\u6765\u786e\u5b9a\u4e0e\u4e4b\u5bf9\u5e94\u7684value\u7684\u4f4d\u7f6e\uff0c\u56e0\u6b64\u4efb\u4f55\u4f5c\u4e3akey\u7684\u5bf9\u8c61\u90fd\u5fc5\u987b\u5b9e\u73b0hashCode\u548cequals\u65b9\u6cd5\u3002
\nhashCode\u548cequals\u65b9\u6cd5\u7ee7\u627f\u81ea\u6839\u7c7bObject\uff0c\u5982\u679c\u4f60\u7528\u81ea\u5b9a\u4e49\u7684\u7c7b\u5f53\u4f5ckey\u7684\u8bdd\uff0c\u8981\u76f8\u5f53\u5c0f\u5fc3\uff0c\u6309\u7167\u6563\u5217\u51fd\u6570\u7684\u5b9a\u4e49\uff0c\u5982\u679c\u4e24\u4e2a\u5bf9\u8c61\u76f8\u540c\uff0c\u5373
\nobj1.equals(obj2)=true\uff0c\u5219\u5b83\u4eec\u7684hashCode\u5fc5\u987b\u76f8\u540c\uff0c\u4f46\u5982\u679c\u4e24\u4e2a\u5bf9\u8c61\u4e0d\u540c\uff0c\u5219\u5b83\u4eec\u7684hashCode\u4e0d\u4e00\u5b9a\u4e0d\u540c\uff0c\u5982\u679c\u4e24\u4e2a\u4e0d\u540c\u5bf9\u8c61\u7684hashCode
\n\u76f8\u540c\uff0c\u8fd9\u79cd\u73b0\u8c61\u79f0\u4e3a\u51b2\u7a81\uff0c\u51b2\u7a81\u4f1a\u5bfc\u81f4\u64cd\u4f5c\u54c8\u5e0c\u8868\u7684\u65f6\u95f4\u5f00\u9500\u589e\u5927\uff0c\u6240\u4ee5\u5c3d\u91cf\u5b9a\u4e49\u597d\u7684hashCode()\u65b9\u6cd5\uff0c\u80fd\u52a0\u5feb\u54c8\u5e0c\u8868\u7684\u64cd\u4f5c\u3002
\n\u5982\u679c\u76f8\u540c\u7684\u5bf9\u8c61\u6709\u4e0d\u540c\u7684hashCode\uff0c\u5bf9\u54c8\u5e0c\u8868\u7684\u64cd\u4f5c\u4f1a\u51fa\u73b0\u610f\u60f3\u4e0d\u5230\u7684\u7ed3\u679c\uff08\u671f\u5f85\u7684get\u65b9\u6cd5\u8fd4\u56denull\uff09\uff0c\u8981\u907f\u514d\u8fd9\u79cd\u95ee\u9898\uff0c\u53ea\u9700\u8981\u7262\u8bb0
\n\u4e00\u6761\uff1a\u8981\u540c\u65f6\u590d\u5199equals\u65b9\u6cd5\u548chashCode\u65b9\u6cd5\uff0c\u800c\u4e0d\u8981\u53ea\u5199\u5176\u4e2d\u4e00\u4e2a\u3002
\nHashtable\u662f\u540c\u6b65\u7684\u3002<\/p>\n

HashMap\u7c7b<\/strong>
\nHashMap\u548cHashtable\u7c7b\u4f3c\uff0c\u4e0d\u540c\u4e4b\u5904\u5728\u4e8eHashMap\u662f\u975e\u540c\u6b65\u7684\uff0c\u5e76\u4e14\u5141\u8bb8null\uff0c\u5373null value\u548cnull key\u3002\uff0c\u4f46\u662f\u5c06HashMap\u89c6\u4e3aCollection\u65f6
\n\uff08values()\u65b9\u6cd5\u53ef\u8fd4\u56deCollection\uff09\uff0c\u5176\u8fed\u4ee3\u5b50\u64cd\u4f5c\u65f6\u95f4\u5f00\u9500\u548cHashMap\u7684\u5bb9\u91cf\u6210\u6bd4\u4f8b\u3002\u56e0\u6b64\uff0c\u5982\u679c\u8fed\u4ee3\u64cd\u4f5c\u7684\u6027\u80fd\u76f8\u5f53\u91cd\u8981\u7684\u8bdd\uff0c\u4e0d\u8981\u5c06
\nHashMap\u7684\u521d\u59cb\u5316\u5bb9\u91cf\u8bbe\u5f97\u8fc7\u9ad8\uff0c\u6216\u8005load factor\u8fc7\u4f4e\u3002<\/p>\n

WeakHashMap\u7c7b<\/strong>
\nWeakHashMap\u662f\u4e00\u79cd\u6539\u8fdb\u7684HashMap\uff0c\u5b83\u5bf9key\u5b9e\u884c\u201c\u5f31\u5f15\u7528\u201d\uff0c\u5982\u679c\u4e00\u4e2akey\u4e0d\u518d\u88ab\u5916\u90e8\u6240\u5f15\u7528\uff0c\u90a3\u4e48\u8be5key\u53ef\u4ee5\u88abGC\u56de\u6536\u3002<\/p>\n

\u603b\u7ed3<\/h3>\n

\u5982\u679c\u6d89\u53ca\u5230\u5806\u6808\uff0c\u961f\u5217\u7b49\u64cd\u4f5c\uff0c\u5e94\u8be5\u8003\u8651\u7528List\uff0c\u5bf9\u4e8e\u9700\u8981\u5feb\u901f\u63d2\u5165\uff0c\u5220\u9664\u5143\u7d20\uff0c\u5e94\u8be5\u4f7f\u7528LinkedList\uff0c\u5982\u679c\u9700\u8981\u5feb\u901f\u968f\u673a\u8bbf\u95ee\u5143\u7d20\uff0c
\n\u5e94\u8be5\u4f7f\u7528ArrayList\u3002
\n\u5982\u679c\u7a0b\u5e8f\u5728\u5355\u7ebf\u7a0b\u73af\u5883\u4e2d\uff0c\u6216\u8005\u8bbf\u95ee\u4ec5\u4ec5\u5728\u4e00\u4e2a\u7ebf\u7a0b\u4e2d\u8fdb\u884c\uff0c\u8003\u8651\u975e\u540c\u6b65\u7684\u7c7b\uff0c\u5176\u6548\u7387\u8f83\u9ad8\uff0c\u5982\u679c\u591a\u4e2a\u7ebf\u7a0b\u53ef\u80fd\u540c\u65f6\u64cd\u4f5c\u4e00\u4e2a\u7c7b\uff0c\u5e94\u8be5
\n\u4f7f\u7528\u540c\u6b65\u7684\u7c7b\u3002
\n\u8981\u7279\u522b\u6ce8\u610f\u5bf9\u54c8\u5e0c\u8868\u7684\u64cd\u4f5c\uff0c\u4f5c\u4e3akey\u7684\u5bf9\u8c61\u8981\u6b63\u786e\u590d\u5199equals\u548chashCode\u65b9\u6cd5\u3002
\n\u5c3d\u91cf\u8fd4\u56de\u63a5\u53e3\u800c\u975e\u5b9e\u9645\u7684\u7c7b\u578b\uff0c\u5982\u8fd4\u56deList\u800c\u975eArrayList\uff0c\u8fd9\u6837\u5982\u679c\u4ee5\u540e\u9700\u8981\u5c06ArrayList\u6362\u6210LinkedList\u65f6\uff0c\u5ba2\u6237\u7aef\u4ee3\u7801\u4e0d\u7528\u6539\u53d8\u3002\u8fd9\u5c31\u662f\u9488\u5bf9\u62bd\u8c61\u7f16\u7a0b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u7ebf\u6027\u8868\uff0c\u94fe\u8868\uff0c\u54c8\u5e0c\u8868\u662f\u5e38\u7528\u7684\u6570\u636e\u7ed3\u6784\uff0c\u5728\u8fdb\u884cJava\u5f00\u53d1\u65f6\uff0cJDK\u5df2\u7ecf\u4e3a\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u7cfb\u5217\u76f8\u5e94\u7684\u7c7b\u6765\u5b9e\u73b0\u57fa\u672c\u7684\u6570 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/169"}],"collection":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=169"}],"version-history":[{"count":9,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/169\/revisions"}],"predecessor-version":[{"id":1564,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=\/wp\/v2\/posts\/169\/revisions\/1564"}],"wp:attachment":[{"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=169"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=169"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ai.zhousir.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=169"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}