{"id":203931,"date":"2025-05-22T12:25:16","date_gmt":"2025-05-22T04:25:16","guid":{"rendered":"https:\/\/server.hk\/cnblog\/203931\/"},"modified":"2025-05-22T12:25:16","modified_gmt":"2025-05-22T04:25:16","slug":"java-list-toarray%e6%96%b9%e6%b3%95%ef%bc%9a%e4%b8%ba%e4%bb%80%e4%b9%88%e4%bc%a0%e5%85%a5%e6%95%b0%e7%bb%84%e6%af%94list%e9%95%bf%e6%97%b6%e7%bb%93%e6%9e%9c%e5%b9%b6%e9%9d%9e%e9%a2%84%e6%9c%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/203931\/","title":{"rendered":"Java List.toArray\u65b9\u6cd5\uff1a\u4e3a\u4ec0\u4e48\u4f20\u5165\u6570\u7ec4\u6bd4List\u957f\u65f6\u7ed3\u679c\u5e76\u975e\u9884\u671f\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

Java List.toArray\u65b9\u6cd5\uff1a\u4e3a\u4ec0\u4e48\u4f20\u5165\u6570\u7ec4\u6bd4List\u957f\u65f6\u7ed3\u679c\u5e76\u975e\u9884\u671f\uff1f<\/h1>\n

\u54c8\u55bd\uff01\u4eca\u5929\u5fc3\u8840\u6765\u6f6e\u7ed9\u5927\u5bb6\u5e26\u6765\u4e86\u300aJava List.toArray\u65b9\u6cd5\uff1a\u4e3a\u4ec0\u4e48\u4f20\u5165\u6570\u7ec4\u6bd4List\u957f\u65f6\u7ed3\u679c\u5e76\u975e\u9884\u671f\uff1f\u300b<\/span>\uff0c\u60f3\u5fc5\u5927\u5bb6\u5e94\u8be5\u5bf9\u6587\u7ae0<\/span>\u90fd\u4e0d\u964c\u751f\u5427\uff0c\u90a3\u4e48\u9605\u8bfb\u672c\u6587\u5c31\u90fd\u4e0d\u4f1a\u5f88\u56f0\u96be\uff0c\u4ee5\u4e0b\u5185\u5bb9\u4e3b\u8981\u6d89\u53ca\u5230<\/span>\uff0c\u82e5\u662f\u4f60\u6b63\u5728\u5b66\u4e60\u6587\u7ae0<\/span>\uff0c\u5343\u4e07\u522b\u9519\u8fc7\u8fd9\u7bc7\u6587\u7ae0~\u5e0c\u671b\u80fd\u5e2e\u52a9\u5230\u4f60\uff01<\/p>\n

<\/p>\n

java \u4e2d\u7684 list.toarray<\/strong><\/p>\n

\u5f53\u6211\u4eec\u4f7f\u7528 list.toarray \u65b9\u6cd5\u5c06 list \u8f6c\u6362\u4e3a\u6570\u7ec4\u65f6\uff0c\u53ef\u80fd\u4f1a\u9047\u5230\u4e0e\u9884\u671f\u4e0d\u540c\u7684\u7ed3\u679c\u3002\u4f8b\u5982\uff1a<\/p>\n

list<integer> list = list.of(12, 34, 56);\ninteger[] array = list.toarray(new integer[]{1, 2, 1, 43, 32, 1});\nsystem.out.println(arrays.tostring(array));<\/pre>\n
\u9884\u671f\u8f93\u51fa\uff1a<\/strong> [12, 34, 56, null, null, null]<\/p>\n
\u5b9e\u9645\u8f93\u51fa\uff1a<\/strong> [12, 34, 56, null, 32, 1]<\/p>\n
\u4e3a\u4ec0\u4e48\u4f1a\u8fd9\u6837\u5462\uff1f<\/p>\n
\u8ba9\u6211\u4eec\u6df1\u5165\u4e86\u89e3 toarray \u65b9\u6cd5\u7684\u6587\u6863\u8bf4\u660e\uff1a<\/p>\n
“\u5982\u679c\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\u6bd4\u5217\u8868\u591a\uff08\u5373\u6570\u7ec4\u5177\u6709\u6bd4\u5217\u8868\u66f4\u591a\u7684\u5143\u7d20\uff09\uff0c\u6570\u7ec4\u4e2d\u7d27\u8ddf\u5728\u5217\u8868\u672b\u5c3e\u540e\u7684\u5143\u7d20\u5c06\u8bbe\u7f6e\u4e3a null\u3002\uff08\u8fd9\u5728\u4ec5<\/strong>\u5f53\u8c03\u7528\u8005\u77e5\u9053\u5217\u8868\u4e0d\u5305\u542b\u4efb\u4f55 null \u5143\u7d20\u7684\u60c5\u51b5\u4e0b\u786e\u5b9a\u5217\u8868\u7684\u957f\u5ea6\u65f6\u5f88\u6709\u7528\u3002\uff09”<\/p>\n
\u8fd9\u610f\u5473\u7740\uff0c\u5982\u679c\u6570\u7ec4\u7684\u5143\u7d20\u6bd4\u5217\u8868\u591a\uff0c\u5219\u7d27\u8ddf\u5728\u5217\u8868\u672b\u5c3e\u540e\u9762\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u5c06\u88ab\u8bbe\u7f6e\u4e3a null\u3002\u8fd9\u6709\u52a9\u4e8e\u5728\u8c03\u7528\u8005\u5f97\u77e5\u5217\u8868\u4e0d\u5305\u542b\u4efb\u4f55 null \u5143\u7d20\u65f6\u63a8\u65ad\u51fa\u5217\u8868\u7684\u771f\u5b9e\u957f\u5ea6\u3002<\/p>\n
\u5728\u7ed9\u51fa\u7684\u4ee3\u7801\u793a\u4f8b\u4e2d\uff0c\u6570\u7ec4\u7684\u5143\u7d20\uff086 \u4e2a\uff09\u6bd4\u5217\u8868\u4e2d\u7684\u5143\u7d20\uff083 \u4e2a\uff09\u591a\u3002\u56e0\u6b64\uff0c\u5217\u8868\u672b\u5c3e\u540e\u9762\u7684\u7b2c\u4e00\u4e2a\u6570\u7ec4\u5143\u7d20\u88ab\u8bbe\u7f6e\u4e3a null\uff0c\u4ece\u800c\u4ea7\u751f\u5b9e\u9645\u7684\u8f93\u51fa\u7ed3\u679c\u3002<\/p>\n
\u8fd9\u4e2a\u884c\u4e3a\u5728 arraylist \u7684\u5b9e\u73b0\u4e2d\u5f97\u5230\u8bc1\u660e\uff1a<\/p>\n
public &lt;T&gt; T[] toArray(T[] a) {\n    if (a.length &lt; size)\n        \/\/ Make a new array of a's runtime type, but my contents:\n        return (T[]) Arrays.copyOf(elementData, size, a.getClass());\n    System.arraycopy(elementData, 0, a, 0, size);\n    if (a.length &gt; size)\/\/\u5982\u679c\u6570\u7ec4\u7684\u957f\u5ea6\u5927\u4e8e\u5217\u8868\uff0c\u628a\u5217\u8868\u540e\u9762\u7684\u7b2c\u4e00\u4e2a\u4f4d\u7f6e\u7f6e\u4e3anull\n        a[size] = null;\n    return a;\n}<\/pre>\n
\u672c\u7bc7\u5173\u4e8e\u300aJava List.toArray\u65b9\u6cd5\uff1a\u4e3a\u4ec0\u4e48\u4f20\u5165\u6570\u7ec4\u6bd4List\u957f\u65f6\u7ed3\u679c\u5e76\u975e\u9884\u671f\uff1f\u300b\u7684\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\u5566\uff0c\u4f46\u662f\u5b66\u65e0\u6b62\u5883\uff0c\u60f3\u8981\u4e86\u89e3\u5b66\u4e60\u66f4\u591a\u5173\u4e8e\u6587\u7ae0\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u8bf7\u5173\u6ce8\u516c\u4f17\u53f7\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
Java List.toArra...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-203931","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203931","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=203931"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/203931\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=203931"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=203931"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=203931"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}