{"id":4011,"date":"2025-07-28T21:40:44","date_gmt":"2025-07-28T13:40:44","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=4011"},"modified":"2025-07-28T21:40:44","modified_gmt":"2025-07-28T13:40:44","slug":"hashtable-%e4%b8%8e-concurrenthashmap-%e7%9a%84%e5%8c%ba%e5%88%ab%e6%98%af%e4%bb%80%e4%b9%88%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/07\/28\/hashtable-%e4%b8%8e-concurrenthashmap-%e7%9a%84%e5%8c%ba%e5%88%ab%e6%98%af%e4%bb%80%e4%b9%88%ef%bc%9f\/","title":{"rendered":"Hashtable\u00a0\u4e0e\u00a0ConcurrentHashMap\u00a0\u7684\u533a\u522b\u662f\u4ec0\u4e48\uff1f"},"content":{"rendered":"\n<p>\u4ee5\u4e0b\u662f <strong><code>Hashtable<\/code> \u4e0e <code>ConcurrentHashMap<\/code> \u7684\u8be6\u7ec6\u5168\u9762\u5bf9\u6bd4\u5206\u6790<\/strong>\uff0c\u5305\u62ec\u8bbe\u8ba1\u7406\u5ff5\u3001\u5b9e\u73b0\u539f\u7406\u3001\u6027\u80fd\u5dee\u5f02\u3001\u4f7f\u7528\u573a\u666f\u7b49\uff0c\u5e76\u9644\u4e0a\u5b9e\u6218\u5efa\u8bae\u548c\u6e90\u7801\u8bf4\u660e\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e00\u3001<code>Hashtable<\/code> \u4e0e <code>ConcurrentHashMap<\/code> \u603b\u4f53\u5bf9\u6bd4\u8868<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7279\u6027<\/th><th><code>Hashtable<\/code><\/th><th><code>ConcurrentHashMap<\/code><\/th><\/tr><\/thead><tbody><tr><td>\u662f\u5426\u7ebf\u7a0b\u5b89\u5168<\/td><td>\u662f\uff08\u5168\u65b9\u6cd5\u540c\u6b65\uff09<\/td><td>\u662f\uff08\u5206\u6bb5\u9501\u6216CAS\u673a\u5236\uff0c\u7c92\u5ea6\u66f4\u7ec6\uff09<\/td><\/tr><tr><td>\u9501\u673a\u5236<\/td><td>\u7c97\u7c92\u5ea6\u9501\uff1a\u65b9\u6cd5\u7ea7 <code>synchronized<\/code><\/td><td>\u7cbe\u7ec6\u5316\u9501\uff1a\u6bcf\u4e2a\u6876\/\u6bb5\u4f7f\u7528\u9501\u6216 CAS \u64cd\u4f5c<\/td><\/tr><tr><td>\u662f\u5426\u5141\u8bb8 null key\/value<\/td><td> \u5168\u90e8\u4e0d\u5141\u8bb8<\/td><td> key \u4e0d\u5141\u8bb8\uff0cvalue \u5141\u8bb8\u4e3a null<\/td><\/tr><tr><td>\u6027\u80fd<\/td><td>\u8f83\u4f4e\uff1a\u56e0\u5168\u65b9\u6cd5\u9501\uff0c\u5b58\u5728\u963b\u585e<\/td><td>\u9ad8\u6027\u80fd\uff1a\u9ad8\u5e76\u53d1\u73af\u5883\u8868\u73b0\u4f18\u8d8a<\/td><\/tr><tr><td>\u5f15\u5165\u7248\u672c<\/td><td>JDK 1.0<\/td><td>JDK 1.5<\/td><\/tr><tr><td>\u63a8\u8350\u4f7f\u7528<\/td><td>\u5df2\u4e0d\u63a8\u8350\u4f7f\u7528<\/td><td>\u73b0\u4ee3\u5e76\u53d1 Map \u63a8\u8350\u4f7f\u7528<\/td><\/tr><tr><td>\u8fed\u4ee3\u5668 fail-fast \u7279\u6027<\/td><td>\u679a\u4e3e\u4e0d fail-fast\uff0c\u6613\u51fa\u73b0\u5e76\u53d1\u95ee\u9898<\/td><td>fail-fast\uff0c\u80fd\u611f\u77e5\u5e76\u53d1\u4fee\u6539<\/td><\/tr><tr><td>\u652f\u6301 Java 8+ \u7ea2\u9ed1\u6811\u4f18\u5316<\/td><td>\u4e0d\u652f\u6301<\/td><td>\u652f\u6301 bucket \u94fe\u8868\u8f6c\u4e3a\u7ea2\u9ed1\u6811\uff08\u63d0\u5347\u67e5\u627e\u6548\u7387\uff09<\/td><\/tr><tr><td>\u5e94\u7528\u573a\u666f<\/td><td>\u9057\u7559\u4ee3\u7801\uff0c\u8f7b\u91cf\u7ebf\u7a0b\u573a\u666f<\/td><td>\u591a\u7ebf\u7a0b\u9ad8\u5e76\u53d1\u73af\u5883\uff0c\u7ebf\u7a0b\u6c60\u3001\u7f13\u5b58\u3001\u5171\u4eab\u6570\u636e\u7b49<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e8c\u3001\u7ebf\u7a0b\u5b89\u5168\u673a\u5236\u8be6\u89e3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. <code>Hashtable<\/code>: \u65b9\u6cd5\u7ea7\u9501<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>public synchronized V get(Object key) { ... }\npublic synchronized V put(K key, V value) { ... }<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u6240\u6709\u65b9\u6cd5\u90fd\u52a0 <code>synchronized<\/code>\uff0c\u5bfc\u81f4\u9ad8\u5e76\u53d1\u4e0b\u7ebf\u7a0b\u963b\u585e\u4e25\u91cd\uff0c<strong>\u65e0\u8bba\u662f\u5426\u8bbf\u95ee\u540c\u4e00 key \u90fd\u4f1a\u4e32\u884c\u5316<\/strong>\u3002<\/p>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">2. <code>ConcurrentHashMap<\/code>: \u5206\u6bb5\u9501 \/ CAS<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">Java 7 \u53ca\u4e4b\u524d\u7248\u672c\uff1a<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f7f\u7528 <strong>Segment\uff08\u5206\u6bb5\uff09\u9501\u673a\u5236<\/strong><\/li>\n\n\n\n<li>\u6bcf\u6bb5\u76f8\u5f53\u4e8e\u4e00\u4e2a\u5c0f\u7684 <code>Hashtable<\/code>\uff0c\u9501\u7c92\u5ea6\u5c0f\uff0c\u591a\u4e2a\u7ebf\u7a0b\u53ef\u540c\u65f6\u8bbf\u95ee\u4e0d\u540c Segment<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">Java 8 \u53ca\u4e4b\u540e\u7248\u672c\uff08\u4e3b\u8981\u4f7f\u7528\uff09\uff1a<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u6452\u5f03\u4e86 Segment\uff0c\u91c7\u7528\uff1a<\/li>\n\n\n\n<li><strong>\u6570\u7ec4 + \u94fe\u8868\/\u7ea2\u9ed1\u6811<\/strong><\/li>\n\n\n\n<li><strong>Node \u8282\u70b9\u7684 synchronized + CAS + volatile<\/strong><\/li>\n\n\n\n<li>\u63d0\u4f9b <strong>\u66f4\u9ad8\u6027\u80fd\u548c\u66f4\u5c0f\u9501\u7ade\u4e89<\/strong><\/li>\n<\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code>\/\/ putVal \u5185\u90e8\u4f2a\u4ee3\u7801\nif (tabAt(table, i) == null) {\n    CAS \u63d2\u5165\u9996\u4e2a\u8282\u70b9\uff1b\n} else {\n    synchronized (bucket) {\n        \/\/ \u94fe\u8868\u6216\u7ea2\u9ed1\u6811\u63d2\u5165\u64cd\u4f5c\n    }\n}<\/code><\/pre>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u66f4\u9002\u7528\u4e8e <strong>\u9ad8\u5e76\u53d1\u73af\u5883\uff08Web\u670d\u52a1\u5668\u3001\u7f13\u5b58\u3001\u7ebf\u7a0b\u6c60\u6570\u636e\u4f20\u9012\u7b49\uff09<\/strong>\u3002<\/p>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e09\u3001\u4e3a\u4ec0\u4e48\u4e0d\u518d\u63a8\u8350\u4f7f\u7528 <code>Hashtable<\/code><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8bbe\u8ba1\u592a\u65e9\uff0c\u672a\u8003\u8651\u9ad8\u5e76\u53d1\u6027\u80fd<\/li>\n\n\n\n<li>\u5168\u65b9\u6cd5\u540c\u6b65\u6548\u7387\u4f4e\u4e0b<\/li>\n\n\n\n<li>\u6ca1\u6709 <code>ConcurrentModificationException<\/code>\uff0c\u5e76\u53d1\u4e0b\u6570\u636e\u4e0d\u4e00\u81f4\u98ce\u9669\u5927<\/li>\n\n\n\n<li>\u73b0\u4ee3\u9879\u76ee\u51e0\u4e4e\u90fd\u4f7f\u7528 <code>ConcurrentHashMap<\/code> \u66ff\u4ee3<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u56db\u3001\u5b9e\u6218\u4f7f\u7528\u5efa\u8bae<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">\u63a8\u8350\u4f7f\u7528 <code>ConcurrentHashMap<\/code> \u66ff\u4ee3\u573a\u666f<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u4f7f\u7528\u573a\u666f<\/th><th>\u63a8\u8350\u505a\u6cd5<\/th><\/tr><\/thead><tbody><tr><td>\u7ebf\u7a0b\u95f4\u5171\u4eab\u7f13\u5b58<\/td><td>\u4f7f\u7528 <code>ConcurrentHashMap<\/code> \u505a\u7f13\u5b58 Map<\/td><\/tr><tr><td>Web \u9879\u76ee\u4e2d\u7684\u4f1a\u8bdd\u6570\u636e<\/td><td>\u7528 <code>ConcurrentHashMap<\/code> \u5b58\u50a8\u7ebf\u7a0b\u9694\u79bb\u6570\u636e<\/td><\/tr><tr><td>\u9700\u8981\u9ad8\u6027\u80fd\u3001\u9ad8\u5e76\u53d1\u8bfb\u5199\u64cd\u4f5c<\/td><td><code>ConcurrentHashMap<\/code> \u662f\u6700\u4f73\u9009\u62e9<\/td><\/tr><tr><td>\u60f3\u907f\u514d\u9501\u5e26\u6765\u7684\u6027\u80fd\u635f\u8017<\/td><td>\u5229\u7528\u5176\u975e\u963b\u585e\u6216\u5c40\u90e8\u9501\u673a\u5236\uff0c\u63d0\u5347\u541e\u5410\u91cf<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u4e94\u3001\u793a\u4f8b\u4ee3\u7801\u5bf9\u6bd4<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">1. Hashtable \u793a\u4f8b<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>Hashtable&lt;String, String&gt; table = new Hashtable&lt;&gt;();\ntable.put(\"key\", \"value\");\nSystem.out.println(table.get(\"key\"));<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">2. ConcurrentHashMap \u793a\u4f8b<\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>ConcurrentHashMap&lt;String, String&gt; cmap = new ConcurrentHashMap&lt;&gt;();\ncmap.put(\"key\", \"value\");\nSystem.out.println(cmap.get(\"key\"));<\/code><\/pre>\n\n\n\n<p>\u5728\u9ad8\u5e76\u53d1\u60c5\u51b5\u4e0b\uff0c<code>ConcurrentHashMap<\/code> \u652f\u6301\u540c\u65f6\u591a\u4e2a\u7ebf\u7a0b\u5bf9\u4e0d\u540c key \u7684\u5e76\u53d1\u8bbf\u95ee\uff0c\u6027\u80fd\u63d0\u5347\u5de8\u5927\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u516d\u3001\u6df1\u5165\u8d44\u6599\u63a8\u8350<\/h2>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u5185\u5bb9<\/th><th>\u94fe\u63a5<\/th><\/tr><\/thead><tbody><tr><td>\u5b98\u65b9 Javadoc<\/td><td><a href=\"https:\/\/docs.oracle.com\/javase\/8\/docs\/api\/java\/util\/Hashtable.html\">Hashtable<\/a><\/td><\/tr><tr><td>\u5b98\u65b9 Javadoc<\/td><td><a href=\"https:\/\/docs.oracle.com\/javase\/8\/docs\/api\/java\/util\/concurrent\/ConcurrentHashMap.html\">ConcurrentHashMap<\/a><\/td><\/tr><tr><td>\u6e90\u7801\u5206\u6790\u6587\u7ae0<\/td><td><a href=\"https:\/\/www.baeldung.com\/java-concurrenthashmap\">Java ConcurrentHashMap \u6e90\u7801\u89e3\u6790<\/a><\/td><\/tr><tr><td>\u6027\u80fd\u5bf9\u6bd4\u5b9e\u6d4b<\/td><td><a href=\"https:\/\/dzone.com\/articles\/concurrenthashmap-vs-hashtable-performance\">Hashtable vs ConcurrentHashMap \u6027\u80fd\u5bf9\u6bd4<\/a><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">\u603b\u7ed3\u4e00\u53e5\u8bdd<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>\u9664\u975e\u7ef4\u62a4\u975e\u5e38\u8001\u7684\u9057\u7559\u7cfb\u7edf\uff0c\u5426\u5219<strong>\u5e94\u5168\u9762\u6dd8\u6c70 <code>Hashtable<\/code>\uff0c\u4f7f\u7528 <code>ConcurrentHashMap<\/code> \u6765\u6784\u5efa\u7ebf\u7a0b\u5b89\u5168\u7684 Map\u3002<\/strong><\/p>\n<\/blockquote>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4ee5\u4e0b\u662f Hashtable \u4e0e ConcurrentHashMap \u7684\u8be6\u7ec6\u5168\u9762\u5bf9\u6bd4\u5206\u6790\uff0c\u5305\u62ec\u8bbe\u8ba1\u7406\u5ff5\u3001\u5b9e\u73b0\u539f\u7406 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":4012,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[68,86],"tags":[],"class_list":["post-4011","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java","category-java-"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/4011","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=4011"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/4011\/revisions"}],"predecessor-version":[{"id":4013,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/4011\/revisions\/4013"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/4012"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=4011"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=4011"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=4011"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}