{"id":486,"date":"2019-09-29T16:11:01","date_gmt":"2019-09-29T08:11:01","guid":{"rendered":"http:\/\/weitaoc.com\/?p=486"},"modified":"2019-10-11T10:38:49","modified_gmt":"2019-10-11T02:38:49","slug":"java%e9%87%8c%e9%9b%86%e5%90%88%e8%bf%99%e4%ba%9b%e4%ba%8b%e6%83%85-map","status":"publish","type":"post","link":"http:\/\/weitaoc.com\/?p=486","title":{"rendered":"java\u91cc\u96c6\u5408\u8fd9\u4e9b\u4e8b\u60c5-Map"},"content":{"rendered":"\n

\u524d\u9762\u7b80\u5355\u603b\u7ed3\u4e86\u4e00\u4e0b\u96c6\u5408\uff0cMap\u80fd\u8bf4\u7684\u53ef\u591a\u53ef\u5c11\uff0c\u5148\u6309\u7167\u81ea\u5df1\u60f3\u7684\u603b\u7ed3\u5427<\/p><\/blockquote>\n\n\n\n

\u524d\u9762\u8bf4\u5230HashSet\u7684\u65f6\u5019\u4e5f\u63d0\u5230\u4e00\u70b9\uff0cHashSet\u7684\u5b9e\u73b0\u5176\u5b9e\u5c31\u662fHashMap\uff0c\u6240\u4ee5HashMap\u7684\u91cd\u590d\u6027\u6821\u9a8c\u4e5f\u662f\u57fa\u4e8eHashCode\u548cequals\uff0c\u6240\u4ee5\u5bf9\u4e8e\u5bf9\u8c61\u6765\u8bf4\uff0c\u91cd\u5199HashCode\u548cequals\u662f\u975e\u8981\u91cd\u8981\u7684\u3002<\/p>\n\n\n\n

HashMap\u7684\u6570\u636e\u7ed3\u6784\u662f\u54c8\u5e0c\u8868\uff0c\u54c8\u5e0c\u8868\u7684\u5bb9\u91cf\u5728Map\u521d\u59cb\u5316\u65f6\u5c31\u4f1a\u8bbe\u5b9a\uff0c\u9ed8\u8ba4\u4e3a16\uff0c\u8fd8\u6709\u4e00\u4e2a\u9ed8\u8ba4\u503c\u662f\u52a0\u8f7d\u56e0\u5b500.75\uff0c\u8fd9\u4e2a\u52a0\u8f7d\u56e0\u5b50\u7684\u542b\u4e49\u662f\uff0c\u5f53Map\u7684\u771f\u5b9e\u5bb9\u91cf\u5230\u8fbe\u4e86\u5f53\u524d\u6700\u5927\u5bb9\u91cf\u76840.75\u500d\uff0c\u5c31\u4f1a\u7acb\u5373\u8fdb\u884c\u6269\u5bb9\u64cd\u4f5c\u3002<\/p>\n\n\n\n

\u524d\u9762\u4e5f\u63d0\u5230\u4e86\u6570\u636e\u7ed3\u6784\uff0c\u6570\u7ec4\u548c\u94fe\u8868\uff0c\u4e24\u79cd\u65b9\u5f0f\u7684\u4f18\u7f3a\u70b9\uff0c\u54c8\u5e0c\u8868\u7684\u6570\u636e\u7ed3\u6784\u662f\u6570\u7ec4\u548c\u94fe\u8868\u7684\u7ed3\u5408\uff0c\u6839\u636ekey\u8fdb\u884chash\u6563\u5217\u6210\u6570\u7ec4\u7ed3\u6784 (\u5e76\u4e0d\u662f\u4e00\u4e2aHash\u4e00\u4e2a\u6876\uff0c\u901a\u5e38\u662f\u901a\u8fc7\u628aHash\u518d\u53d6\u6a21\u653e\u5165\u4e00\u4e2a\u6876 h & (table.length -1)\uff0cHash\u7b97\u6cd5\u672c\u8d28\u4e0a\u662f\u4e09\u6b65\uff1a\u53d6key\u7684hashCode\u503c\u3001\u9ad8\u4f4d\u8fd0\u7b97\u3001\u53d6\u6a21\u8fd0\u7b97<\/strong>)\uff0c\u6bcf\u4e2a\u6876\u53ef\u80fd\u4f1a\u5b58\u5728\u591a\u4e2a\u5bf9\u8c61(\u53d1\u751f\u78b0\u649e)\uff0c\u4f1a\u628a\u8fd9\u4e9bhash\u540e\u7684\u5bf9\u8c61\u4ee5\u94fe\u8868\u7684\u5f62\u5f0f\u8fdb\u884c\u5b58\u50a8\uff0c\u5f53hashCode\u53d6\u6a21\u5230\u540c\u4e00\u4e2a\u6876\uff0c\u518d\u6839\u636ekey\u5bf9\u94fe\u8868\u7684\u6bcf\u4e00\u4e2a\u503c\u8fdb\u884cequals\u5339\u914d\u53d6\u503c\u3002\u7406\u8bba\u4e0a\u63d0\u9ad8\u4e86\u8bfb\u53d6\u548c\u64cd\u4f5c\u7684\u6548\u7387\uff0c\u540c\u65f6\u4e5f\u5b58\u5728\u4e00\u4e2a\u95ee\u9898\uff0c\u5c31\u662f\u6269\u5bb9\u6548\u7387\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n

\u4e3a\u4ec0\u4e48\u8981\u6269\u5bb9\uff1f\u524d\u9762\u8bf4\u4e86\u4f1a\u628akey\u7684hash\u4e4b\u540e\u53d6\u6a21\u653e\u5165\u4e00\u4e2a\u6876\u4e2d\uff0c\u5f53\u6876\u7684\u6570\u91cf\u6bd4\u8f83\u5c11\uff0c\u53d1\u751f\u78b0\u649e\u7684\u51e0\u7387\u5c31\u6bd4\u8f83\u5927\uff0c\u4e00\u4e2a\u6876\u4e2d\u7684\u94fe\u8868\u957f\u5ea6\u975e\u5e38\u5927\uff0c \u5bfc\u81f4\u67e5\u8be2\u6548\u7387\u964d\u4f4e\uff0c\u8fd9\u65f6\u5c31\u9700\u8981\u505a\u6269\u5bb9\u64cd\u4f5c\uff08\u7406\u8bba\u9700\u8981\uff0c\u4e0d\u662f\u5b9e\u9645\u903b\u8f91\u4e0a\u7684\u6761\u4ef6\uff09\uff0c\u8ba9\u6570\u636e\u5c3d\u91cf\u5206\u5e03\u5747\u5300(\u8c01\u77e5\u9053\u5747\u4e0d\u5747\u5300\u5462)\u3002<\/p>\n\n\n\n

JDK1.8\u91cc\u5bf9\u94fe\u8868\u90e8\u5206\u6709\u5347\u7ea7\uff0c\u5f53\u94fe\u8868\u957f\u5ea6\u5927\u4e8e8\u65f6\uff0c\u5bf9\u8c61\u7684\u5b58\u50a8\u65b9\u5f0f\u53d8\u6210\u4e86\u7ea2\u9ed1\u6811\u8282\u70b9\uff0c\u540c\u6837\uff0c\u5982\u679c\u5220\u9664\u67d0\u4e2aval\uff0c\u5bfc\u81f4\u957f\u5ea6\u5c0f\u4e8e8\uff0c\u4e5f\u4f1a\u5c06\u7ea2\u9ed1\u6811\u8f6c\u6210\u94fe\u8868\u3002\u4e3b\u8981\u662f\u4e3a\u4e86\u9891\u7e41\u53d1\u751f\u78b0\u649e\u5bfc\u81f4\u94fe\u8868\u957f\u5ea6\u8fc7\u957f\uff0c\u67e5\u8be2\u6548\u7387\u964d\u4f4e\u3002<\/p>\n\n\n\n

\n\n
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<\/div><\/td>
for (int binCount = 0; ; ++binCount) {
\n     if ((e = p.next) == null) {
\n         p.next = newNode(hash, key, value, null);
\n         if (binCount >= TREEIFY_THRESHOLD - 1) \/\/ -1 for 1st
\n             \/\/ \u5927\u4e8e8\u65f6\u8f6c\u4e3a\u7ea2\u9ed1\u6811
\n             treeifyBin(tab, hash);
\n         break;
\n     }
\n     if (e.hash == hash &amp;&amp;
\n         ((k = e.key) == key || (key != null &amp;&amp; key.equals(k))))
\n         break;
\n     p = e;
\n }<\/div><\/td><\/tr><\/tbody><\/table><\/div>\n\n<\/pre>\n\n\n\n
HashMap\u6709\u4e2a\u5b50\u7c7bLinkedHashMap\uff0c\u901a\u8fc7\u94fe\u8868\u52a0\u54c8\u5e0c\u6563\u5217\u7684\u65b9\u5f0f\uff0c\u5b9e\u73b0\u4e86\u6709\u5e8f\u6027\u3002<\/p>\n\n\n\n
TreeMap\u548cTreeSet\u6bd4\u8f83\u7c7b\u578b\uff0c\u90fd\u662f\u7ea2\u9ed1\u6811\u7684\u5b9e\u73b0\u65b9\u5f0f\uff0c\u8fd9\u91cc\u5c31\u4e0d\u591a\u8bf4\u4e86\uff0c\u540e\u9762\u4f1a\u4e13\u95e8\u5199\u4e00\u7bc7\u6587\u7ae0\u5bf9\u7ea2\u9ed1\u6811\u8fdb\u884c\u603b\u7ed3\u3002<\/p>\n\n\n\n
\u8fd9\u91cc\u518d\u603b\u7ed3\u4e00\u4e0bMap\u76f8\u5173\u7684\u5185\u5bb9<\/p>\n\n\n\n