{"id":16427,"date":"2023-02-13T16:52:05","date_gmt":"2023-02-13T08:52:05","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=16427"},"modified":"2023-02-13T16:52:08","modified_gmt":"2023-02-13T08:52:08","slug":"hasmmap%e5%92%8chashset%e6%9c%89%e4%bb%80%e4%b9%88%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/16427.html","title":{"rendered":"HasmMap\u548cHashSet\u6709\u4ec0\u4e48\u533a\u522b"},"content":{"rendered":"\n
\n

HasmMap\u548cHashSet\u7684\u533a\u522b\u662f\uff1a1. HashSet\u5b9e\u73b0\u4e86Set\u63a5\u53e3, \u4ec5\u5b58\u50a8\u5bf9\u8c61; HashMap\u5b9e\u73b0\u4e86 Map\u63a5\u53e3, \u5b58\u50a8\u7684\u662f\u952e\u503c\u5bf9\uff1b2. HashSet\u5e95\u5c42\u5176\u5b9e\u662f\u7528HashMap\u5b9e\u73b0\u5b58\u50a8\u7684\uff0cHashSet\u5c01\u88c5\u4e86\u4e00\u7cfb\u5217HashMap\u7684\u65b9\u6cd5. \u4f9d\u9760HashMap\u6765\u5b58\u50a8\u5143\u7d20\u503c\u3002<\/p>\n<\/blockquote>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n

\u4e00\u3001HasmMap\u548cHashSet\u7684\u533a\u522b<\/strong><\/h2>\n\n\n\n

1.HashSet\u5b9e\u73b0\u4e86Set\u63a5\u53e3, \u4ec5\u5b58\u50a8\u5bf9\u8c61; HashMap\u5b9e\u73b0\u4e86 Map\u63a5\u53e3, \u5b58\u50a8\u7684\u662f\u952e\u503c\u5bf9.<\/p>\n\n\n\n

2.HashSet\u5e95\u5c42\u5176\u5b9e\u662f\u7528HashMap\u5b9e\u73b0\u5b58\u50a8\u7684, HashSet\u5c01\u88c5\u4e86\u4e00\u7cfb\u5217HashMap\u7684\u65b9\u6cd5. \u4f9d\u9760HashMap\u6765\u5b58\u50a8\u5143\u7d20\u503c,(\u5229\u7528hashMap\u7684key\u952e\u8fdb\u884c\u5b58\u50a8), \u800cvalue\u503c\u9ed8\u8ba4\u4e3aObject\u5bf9\u8c61. \u6240\u4ee5HashSet\u4e5f\u4e0d\u5141\u8bb8\u51fa\u73b0\u91cd\u590d\u503c, \u5224\u65ad\u6807\u51c6\u548cHashMap\u5224\u65ad\u6807\u51c6\u76f8\u540c, \u4e24\u4e2a\u5143\u7d20\u7684hashCode\u76f8\u7b49\u5e76\u4e14\u901a\u8fc7equals()\u65b9\u6cd5\u8fd4\u56detrue\u3002<\/p>\n\n\n\n

HashSet \u96c6\u5408\u4e0d\u5141\u8bb8\u5b58\u50a8\u76f8\u540c\u7684\u5143\u7d20, \u5b83\u5e95\u5c42\u5b9e\u9645\u4e0a\u4f7f\u7528 HashMap \u6765\u5b58\u50a8\u5143\u7d20\u7684, \u4e0d\u8fc7\u5173\u6ce8\u7684\u53ea\u662fkey\u5143\u7d20, \u6240\u6709 value\u5143\u7d20\u9ed8\u8ba4\u4e3a Object\u7c7b\u5bf9\u8c61\u3002<\/p>\n\n\n\n

HashSet <\/strong>\u7684\u6784\u9020\u65b9\u6cd5<\/strong><\/h3>\n\n\n\n

\/\/HashSet\u5e95\u5c42\u7528\u6765\u5b58\u50a8\u5143\u7d20\u7684\u7ed3\u6784,\u5b9e\u9645\u4e0a\u4f7f\u7528HashMap\u6765\u5b58\u50a8<\/p>\n\n\n\n

private transient HashMap<E,Object> map;<\/p>\n\n\n\n

\/\/HashMap\u4e2d\u7684value\u503c,HashSet\u53ea\u5173\u6ce8key\u503c,\u6240\u4ee5\u6240\u6709\u7684value\u503c\u90fd\u4e3aObject\u5bf9\u8c61<\/p>\n\n\n\n

private static final Object PRESENT = new Object();<\/p>\n\n\n\n

\/\/HashSet\u7684\u65e0\u53c2\u6784\u9020,\u76f4\u63a5\u521b\u5efa\u4e86\u4e00\u4e2aHashMap\u5bf9\u8c61<\/p>\n\n\n\n

public HashSet() {<\/p>\n\n\n\n

        map = new HashMap<>();<\/p>\n\n\n\n

}<\/p>\n\n\n\n

\/\/\u6307\u5b9a\u521d\u59cb\u5316\u5bb9\u91cf\u548c\u8d1f\u8f7d\u56e0\u5b50<\/p>\n\n\n\n

public HashSet(int initialCapacity, float loadFactor) {<\/p>\n\n\n\n

        map = new HashMap<>(initialCapacity, loadFactor);<\/p>\n\n\n\n

}<\/p>\n\n\n\n

\/\/\u7ed9\u5b9a\u521d\u59cb\u5316\u5bb9\u91cf<\/p>\n\n\n\n

public HashSet(int initialCapacity) {<\/p>\n\n\n\n

        map = new HashMap<>(initialCapacity);<\/p>\n\n\n\n

}<\/p>\n\n\n\n

public HashSet(Collection<? extends E> c) {<\/p>\n\n\n\n

        map = new HashMap<>(Math.max((int) (c.size()\/.75f) + 1, 16));<\/p>\n\n\n\n

        addAll(c);<\/p>\n\n\n\n

}<\/p>\n\n\n\n

\u53ef\u4ee5\u770b\u5230 HashSet\u7684\u6784\u9020\u65b9\u6cd5\u5e95\u5c42\u90fd\u662f\u8c03\u7528 HashMap\u7684\u6784\u9020\u65b9\u6cd5, \u6240\u4ee5HashSet\u5e95\u5c42\u5b9e\u9645\u4e0a\u662f\u4f7f\u7528 HashMap \u6765\u4f5c\u4e3a\u5b58\u50a8\u7ed3\u6784.<\/p>\n\n\n\n

\u5f53\u4f7f\u7528\u65e0\u53c2\u6784\u9020\u521b\u5efa HashSet\u5bf9\u8c61\u65f6, \u5176\u5b9e\u8c03\u7528\u4e86 HashMap\u7684\u65e0\u53c2\u6784\u9020\u521b\u5efa\u4e86\u4e00\u4e2a HashMap\u5bf9\u8c61, \u6240\u4ee5 HashSet \u7684\u521d\u59cb\u5316\u5bb9\u91cf\u4e5f\u4e3a16, \u8d1f\u8f7d\u56e0\u5b50\u4e5f\u4e3a 0.75.<\/p>\n\n\n\n

HashSet <\/strong>\u7684 add() \u65b9\u6cd5\u7684\u5b9e\u73b0<\/strong><\/h3>\n\n\n\n

\u53ef\u4ee5\u770b\u5230 HashSet \u7684 add() \u65b9\u6cd5\u5e95\u5c42\u5b9e\u9645\u4e5f\u662f\u8c03\u7528\u4e86 HashMap \u7684 put() \u65b9\u6cd5, \u8fd9\u91cc\u7684key\u4e3a\u6211\u4eec\u4f20\u5165\u7684\u5c06\u8981\u6dfb\u52a0\u5230 set\u96c6\u5408\u4e2d\u7684\u5143\u7d20, \u800cvalue\u503c\u5219\u4e3a PERSENT,\u5176\u5b9e\u5c31\u662f\u4e0a\u9762\u5206\u6790\u7684 HashSet\u7c7b\u4e2d\u7684\u4e00\u4e2a\u9759\u6001\u5b57\u6bb5, \u9ed8\u8ba4\u4e3a Object\u5bf9\u8c61.<\/p>\n\n\n\n

HashSet\u5e76\u4e0d\u5173\u6ce8value\u5143\u7d20, \u53ea\u4f7f\u7528 HashMap\u6765\u5b58\u50a8 key\u5143\u7d20, \u8fd9\u5c31\u4f7f\u5f97 HashSet\u5224\u65ad\u5143\u7d20\u76f8\u7b49\u7684\u6761\u4ef6\u4e0e HashMap\u4e2d key\u76f8\u7b49\u7684\u6761\u4ef6\u5176\u5b9e\u662f\u4e00\u6837\u7684, \u4e24\u4e2a\u5143\u7d20\u7684 hashCode\u503c\u76f8\u540c\u4e14\u901a\u8fc7equals()\u65b9\u6cd5\u6bd4\u8f83\u8fd4\u56de true.<\/p>\n\n\n\n

\u6240\u4ee5HashSet\u5e94\u8be5\u91cd\u5199 equals()\u548chashCode()\u65b9\u6cd5, \u4e24\u4e2a\u5143\u7d20\u7684 HashCode\u76f8\u540c, \u4fdd\u8bc1\u901a\u8fc7equals() \u65b9\u6cd5\u6bd4\u8f83\u8fd4\u56de true<\/p>\n\n\n\n

\u5ef6\u4f38\u9605\u8bfb\uff1a<\/strong><\/p>\n\n\n\n

\u4e8c\u3001HashMap\u4ecb\u7ecd<\/strong><\/h2>\n\n\n\n

HashMap\u5b9e\u73b0\u4e86Map\u63a5\u53e3\uff0cMap\u63a5\u53e3\u5bf9\u952e\u503c\u5bf9\u8fdb\u884c\u6620\u5c04\u3002Map\u4e2d\u4e0d\u5141\u8bb8\u51fa\u73b0\u91cd\u590d\u7684\u952e\uff08Key\uff09\u3002Map\u63a5\u53e3\u6709\u4e24\u4e2a\u57fa\u672c\u7684\u5b9e\u73b0<\/p>\n\n\n\n

TreeMap\u548cHashMap\u3002TreeMap\u4fdd\u5b58\u4e86\u5bf9\u8c61\u7684\u6392\u5217\u6b21\u5e8f\uff0c\u800cHashMap\u4e0d\u80fd\u3002HashMap\u53ef\u4ee5\u6709\u7a7a\u7684\u952e\u503c\u5bf9\uff08Key\uff08null\uff09-Value\uff08null\uff09\uff09<\/p>\n\n\n\n

HashMap\u662f\u975e\u7ebf\u7a0b\u5b89\u5168\u7684\uff08\u975eSynchronize\uff09\uff0c\u8981\u60f3\u5b9e\u73b0\u7ebf\u7a0b\u5b89\u5168\uff0c\u90a3\u4e48\u9700\u8981\u8c03\u7528collections\u7c7b\u7684\u9759\u6001\u65b9\u6cd5synchronizeMap\uff08\uff09\u5b9e\u73b0\u3002<\/p>\n\n\n\n

public Object put(Object Key,Object value)\u65b9\u6cd5\u7528\u6765\u5c06\u5143\u7d20\u6dfb\u52a0\u5230map\u4e2d\u3002<\/p>\n\n\n\n

\u4ee5\u4e0a\u5c31\u662f\u5173\u4e8eHasmMap\u548cHashSet\u6709\u4ec0\u4e48\u533a\u522b\u7684\u5185\u5bb9\u5e0c\u671b\u5bf9\u5927\u5bb6\u6709\u5e2e\u52a9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"HasmMap\u548cHashSet\u7684\u533a\u522b\u662f\uff1a1. HashSet\u5b9e\u73b0\u4e86Set\u63a5\u53e3, \u4ec5\u5b58\u50a8\u5bf9\u8c61; HashMap\u5b9e […]","protected":false},"author":1,"featured_media":16430,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/16427"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=16427"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/16427\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/16430"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=16427"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=16427"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=16427"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}