{"id":295708,"date":"2024-05-20T15:42:24","date_gmt":"2024-05-20T07:42:24","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/295708.html"},"modified":"2024-05-20T15:42:45","modified_gmt":"2024-05-20T07:42:45","slug":"java-%e5%a6%82%e4%bd%95%e8%8e%b7%e5%8f%96%e6%95%b0%e7%bb%84%e4%b8%ad%e7%9a%84-key","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/295708.html","title":{"rendered":"java \u5982\u4f55\u83b7\u53d6\u6570\u7ec4\u4e2d\u7684 key"},"content":{"rendered":"<p style=\"text-align:center\"><img decoding=\"async\" src=\"https:\/\/cdn-kb.worktile.com\/kb\/wp-content\/uploads\/2024\/04\/27143108\/119ef9d4-e4cc-4f7a-87c3-27157d02c36c.webp\" alt=\"java \u5982\u4f55\u83b7\u53d6\u6570\u7ec4\u4e2d\u7684 key\" \/><\/p>\n<p><p>\u6570\u7ec4\u5728Java\u4e2d\u662f\u6709\u5e8f\u7684\u5143\u7d20\u96c6\u5408\uff0c\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\u901a\u8fc7\u4e0b\u6807(index)\u8fdb\u884c\u8bbf\u95ee\uff0c\u7d22\u5f15\u503c\u4ece0\u5f00\u59cb\u76f4\u5230\u6570\u7ec4\u957f\u5ea6\u51cf1\u3002<strong>\u5728Java\u4e2d\u83b7\u53d6\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\uff0c\u5b9e\u9645\u4e0a\u662f\u901a\u8fc7\u6570\u7ec4\u7d22\u5f15\u6765\u5b9e\u73b0\u7684\uff0c\u6570\u7ec4\u672c\u8eab\u5e76\u6ca1\u6709&quot;key&quot;\u7684\u6982\u5ff5\u3002<\/strong><\/p>\n<\/p>\n<p><p>\u5728\u8bf4Java\u6570\u7ec4\u65f6\uff0c\u901a\u5e38\u662f\u6307\u57fa\u672c\u7c7b\u578b\u6570\u7ec4\u6216\u5bf9\u8c61\u6570\u7ec4\u3002\u5bf9\u4e8e\u57fa\u672c\u7c7b\u578b\u6570\u7ec4\uff0c\u5982<code>int[]<\/code>\uff0c<code>double[]<\/code>\u7b49\uff0c\u6bcf\u4e2a\u5143\u7d20\u76f4\u63a5\u5b58\u50a8\u5176\u6570\u503c\uff1b\u800c\u5bf9\u4e8e\u5bf9\u8c61\u6570\u7ec4\uff0c\u4f8b\u5982<code>String[]<\/code>\uff0c<code>Integer[]<\/code>\u7b49\uff0c\u6570\u7ec4\u5b58\u50a8\u7684\u662f\u5bf9\u8c61\u7684\u5f15\u7528\u3002\u4e0d\u8fc7\u4e0d\u7ba1\u662f\u4f55\u79cd\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u8bbf\u95ee\u5176\u5143\u7d20\u7684\u65b9\u5f0f\u76f8\u540c\uff0c\u90fd\u662f\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n<\/p>\n<p><h3>\u4e00\u3001\u7406\u89e3\u6570\u7ec4\u4e0e\u7d22\u5f15<\/h3>\n<\/p>\n<p><p>\u6570\u7ec4\u662f\u56fa\u5b9a\u5927\u5c0f\u7684\uff0c\u4e00\u65e6\u521b\u5efa\u540e\uff0c\u5176\u5927\u5c0f\u4e0d\u80fd\u6539\u53d8\u3002\u6bcf\u4e2a\u6570\u7ec4\u5143\u7d20\u90fd\u53ef\u4ee5\u901a\u8fc7\u8be5\u5143\u7d20\u7684\u7d22\u5f15\u503c\u6765\u5feb\u901f\u8bbf\u95ee\u3002\u7d22\u5f15\u503c\u662f\u6574\u6570\uff0c\u5e76\u4e14\u4e3a\u975e\u8d1f\u6570\u3002\u4f60\u53ef\u4ee5\u8ba4\u4e3a\u6570\u7ec4\u662f\u4e00\u4e2a\u7f16\u53f7\u7684\u5217\u8868\uff0c\u8fd9\u4e9b\u7f16\u53f7\u5373\u662f\u6211\u4eec\u8bf4\u7684\u7d22\u5f15\u503c\u3002<\/p>\n<\/p>\n<p><h4>\u83b7\u53d6\u6570\u7ec4\u957f\u5ea6<\/h4>\n<\/p>\n<p><p>\u83b7\u53d6\u6570\u7ec4\u7684\u957f\u5ea6\u53ef\u4ee5\u501f\u52a9\u6570\u7ec4\u7684<code>length<\/code>\u5c5e\u6027\u3002\u8fd9\u662f\u4e86\u89e3\u6570\u7ec4\u5927\u5c0f\u7684\u91cd\u8981\u6b65\u9aa4\uff0c\u56e0\u4e3a\u4f60\u9700\u8981\u786e\u4fdd\u5728\u8bbf\u95ee\u6570\u7ec4\u65f6\u4e0d\u4f1a\u8d85\u51fa\u5176\u8fb9\u754c\u4ee5\u907f\u514d\u51fa\u73b0<code>ArrayIndexOutOfBoundsException<\/code>\u3002<\/p>\n<\/p>\n<p><pre><code>int[] myArray = {1, 2, 3, 4, 5};<\/p>\n<p>int length = myArray.length; \/\/ \u83b7\u53d6\u6570\u7ec4\u7684\u957f\u5ea6<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h4>\u901a\u8fc7\u7d22\u5f15\u8bbf\u95ee\u6570\u7ec4\u5143\u7d20<\/h4>\n<\/p>\n<p><p>\u4f60\u53ef\u4ee5\u901a\u8fc7\u5728\u65b9\u62ec\u53f7\u4e2d\u63d0\u4f9b\u7d22\u5f15\u503c\u6765\u8bbf\u95ee\u7279\u5b9a\u7684\u6570\u7ec4\u5143\u7d20\u3002<\/p>\n<\/p>\n<p><pre><code>int firstElement = myArray[0]; \/\/ \u8bbf\u95ee\u6570\u7ec4\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20<\/p>\n<p>int lastElement = myArray[myArray.length - 1]; \/\/ \u8bbf\u95ee\u6570\u7ec4\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h3>\u4e8c\u3001\u64cd\u4f5c\u6570\u7ec4\u5143\u7d20<\/h3>\n<\/p>\n<p><p>\u65e2\u7136\u6211\u4eec\u4e86\u89e3\u4e86\u57fa\u672c\u7684\u6570\u7ec4\u548c\u7d22\u5f15\u7684\u6982\u5ff5\uff0c\u63a5\u4e0b\u6765\u6211\u4eec\u5c06\u63a2\u8ba8\u5982\u4f55\u5728\u5b9e\u9645\u7f16\u7a0b\u4e2d\u64cd\u4f5c\u5b83\u4eec\u3002<\/p>\n<\/p>\n<p><h4>\u904d\u5386\u6570\u7ec4<\/h4>\n<\/p>\n<p><p>\u904d\u5386\u6570\u7ec4\u662f\u7f16\u7a0b\u4e2d\u5e38\u89c1\u7684\u64cd\u4f5c\u3002\u53ef\u4ee5\u4f7f\u7528for\u5faa\u73af\u6216\u8005for-each\u5faa\u73af\u6765\u904d\u5386\u6570\u7ec4\u7684\u6bcf\u4e00\u4e2a\u5143\u7d20\u3002<\/p>\n<\/p>\n<p><pre><code>\/\/ \u4f7f\u7528\u5e38\u89c4for\u5faa\u73af\u904d\u5386\u6570\u7ec4<\/p>\n<p>for (int i = 0; i &lt; myArray.length; i++) {<\/p>\n<p>    System.out.println(&quot;Element at index &quot; + i + &quot; is: &quot; + myArray[i]);<\/p>\n<p>}<\/p>\n<p>\/\/ \u4f7f\u7528for-each\u5faa\u73af\u904d\u5386\u6570\u7ec4<\/p>\n<p>for (int element : myArray) {<\/p>\n<p>    System.out.println(&quot;Element is: &quot; + element);<\/p>\n<p>}<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h4>\u4fee\u6539\u6570\u7ec4\u5143\u7d20<\/h4>\n<\/p>\n<p><p>\u4fee\u6539\u6570\u7ec4\u5143\u7d20\u540c\u6837\u901a\u8fc7\u7d22\u5f15\u6765\u5b8c\u6210\u3002\u4f60\u9009\u62e9\u8981\u4fee\u6539\u7684\u5143\u7d20\u7684\u7d22\u5f15\uff0c\u7136\u540e\u4e3a\u5176\u8d4b\u4e88\u4e00\u4e2a\u65b0\u503c\u3002<\/p>\n<\/p>\n<p><pre><code>myArray[0] = 10; \/\/ \u5c06\u6570\u7ec4\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u66f4\u6539\u4e3a10<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h3>\u4e09\u3001\u6570\u7ec4\u7684\u590d\u5236\u4e0e\u6269\u5c55<\/h3>\n<\/p>\n<p><p>\u867d\u7136Java\u6570\u7ec4\u4e00\u65e6\u521b\u5efa\u5927\u5c0f\u4e0d\u53d8\uff0c\u4f46\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u521b\u5efa\u65b0\u7684\u6570\u7ec4\u5e76\u590d\u5236\u5143\u7d20\u6765&quot;\u4f2a\u88c5&quot;\u6539\u53d8\u6570\u7ec4\u5927\u5c0f\u3002<\/p>\n<\/p>\n<p><h4>\u6570\u7ec4\u590d\u5236<\/h4>\n<\/p>\n<p><pre><code>int[] anotherArray = new int[myArray.length];<\/p>\n<p>System.arraycopy(myArray, 0, anotherArray, 0, myArray.length); \/\/ \u590d\u5236\u6570\u7ec4<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h4>\u6570\u7ec4\u6269\u5c55<\/h4>\n<\/p>\n<p><p>\u82e5\u8981\u6269\u5c55\u6570\u7ec4\uff0c\u4f60\u9700\u8981\u521b\u5efa\u4e00\u4e2a\u66f4\u5927\u7684\u65b0\u6570\u7ec4\u5e76\u5c06\u65e7\u6570\u7ec4\u7684\u5185\u5bb9\u590d\u5236\u5230\u65b0\u6570\u7ec4\u4e2d\u3002<\/p>\n<\/p>\n<p><pre><code>int[] extendedArray = new int[10]; \/\/ \u5047\u5b9a\u60f3\u8981\u6269\u5c55\u523010\u4e2a\u5143\u7d20<\/p>\n<p>System.arraycopy(myArray, 0, extendedArray, 0, myArray.length); \/\/ \u590d\u5236\u65e7\u6570\u7ec4\u5230\u65b0\u6570\u7ec4<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h3>\u56db\u3001\u591a\u7ef4\u6570\u7ec4<\/h3>\n<\/p>\n<p><p>Java\u4e0d\u4ec5\u652f\u6301\u5355\u7ef4\u6570\u7ec4\uff0c\u8fd8\u652f\u6301\u591a\u7ef4\u6570\u7ec4\uff0c\u5373\u6570\u7ec4\u7684\u6570\u7ec4\u3002\u5728\u591a\u7ef4\u6570\u7ec4\u4e2d\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u591a\u4e2a\u7d22\u5f15\u6765\u8bbf\u95ee\u5143\u7d20\u3002<\/p>\n<\/p>\n<p><h4>\u521b\u5efa\u591a\u7ef4\u6570\u7ec4<\/h4>\n<\/p>\n<p><pre><code>int[][] twoDimensionalArray = new int[3][2]; \/\/ \u521b\u5efa\u4e00\u4e2a\u67093\u884c2\u5217\u7684\u4e8c\u7ef4\u6570\u7ec4<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><h4>\u5982\u4f55\u8bbf\u95ee\u591a\u7ef4\u6570\u7ec4\u7684\u5143\u7d20<\/h4>\n<\/p>\n<p><pre><code>int element = twoDimensionalArray[0][1]; \/\/ \u8bbf\u95ee\u4e8c\u7ef4\u6570\u7ec4\u4e2d\u7684\u5143\u7d20<\/p>\n<p><\/code><\/pre>\n<\/p>\n<p><p>\u5173\u95ed\u65f6\uff0c\u53ef\u4ee5\u8bf4\u6570\u7ec4\u7684\u4f7f\u7528\u662fJava\u7f16\u7a0b\u7684\u57fa\u7840\u4e4b\u4e00\u3002\u7406\u89e3\u5982\u4f55\u901a\u8fc7\u7d22\u5f15\u6765\u8bbf\u95ee\u548c\u64cd\u4f5c\u6570\u7ec4\u5143\u7d20\u5bf9\u4e8e\u6210\u4e3a\u4e00\u540d\u719f\u7ec3\u7684Java\u7a0b\u5e8f\u5458\u81f3\u5173\u91cd\u8981\u3002\u5c3d\u7ba1\u6570\u7ec4\u7ed3\u6784\u7b80\u5355\uff0c\u4f46\u5176\u5728\u7f16\u5199\u9ad8\u6548\u7a0b\u5e8f\u65f6\u626e\u6f14\u7740\u57fa\u672c\u4e14\u6838\u5fc3\u7684\u89d2\u8272\u3002\u8bb0\u4f4f\uff0c\u6570\u7ec4\u7684\u7d22\u5f15\u662f\u57fa\u4e8e\u96f6\u7684\uff0c\u6b63\u786e\u5730\u5904\u7406\u7d22\u5f15\u5c06\u4f7f\u4f60\u907f\u514d\u8bb8\u591a\u5e38\u89c1\u7684\u7f16\u7a0b\u9519\u8bef\u3002<\/p>\n<\/p>\n<h2><strong>\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n<ol>\n<li>\n<p><strong>\u5728 Java \u4e2d\uff0c\u6570\u7ec4\u662f\u6309\u7167\u7d22\u5f15\u6765\u5b58\u50a8\u548c\u8bbf\u95ee\u6570\u636e\u7684<\/strong>\uff0c\u5e76\u4e14\u4e0d\u50cf\u952e\u503c\u5bf9\u7684\u6570\u636e\u7ed3\u6784\u90a3\u6837\u6709\u4e00\u4e2a\u660e\u786e\u7684\u952e\u3002\u6240\u4ee5\uff0c\u6570\u7ec4\u4e2d\u6ca1\u6709\u6240\u8c13\u7684\u201ckey\u201d\u3002\u5982\u679c\u4f60\u60f3\u901a\u8fc7\u7279\u5b9a\u7684\u952e\u6765\u8bbf\u95ee\u6570\u7ec4\u4e2d\u7684\u503c\uff0c\u4f60\u9700\u8981\u4f7f\u7528\u5176\u4ed6\u6570\u636e\u7ed3\u6784\u5982 Map \u6216\u8005 Set\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u5982\u679c\u4f60\u8981\u83b7\u53d6\u6570\u7ec4\u4e2d\u67d0\u4e2a\u7279\u5b9a\u7684\u5143\u7d20\u7684\u503c\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u7d22\u5f15\u6765\u5b9e\u73b0<\/strong>\u3002\u5728 Java \u4e2d\uff0c\u6570\u7ec4\u7684\u7d22\u5f15\u4ece 0 \u5f00\u59cb\uff0c\u901a\u8fc7\u4f7f\u7528\u65b9\u62ec\u53f7\u52a0\u4e0a\u7d22\u5f15\u6765\u83b7\u53d6\u6307\u5b9a\u4f4d\u7f6e\u4e0a\u7684\u5143\u7d20\u3002\u4f8b\u5982\uff0c\u8981\u83b7\u53d6\u6570\u7ec4\u4e2d\u7b2c\u4e00\u4e2a\u5143\u7d20\u7684\u503c\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>array[0]<\/code>\u3002<\/p>\n<\/li>\n<li>\n<p><strong>\u5982\u679c\u4f60\u5e0c\u671b\u6839\u636e\u6570\u7ec4\u4e2d\u7684\u67d0\u4e2a\u503c\u6765\u8fdb\u884c\u67e5\u627e\uff0c\u5e76\u8fd4\u56de\u8be5\u503c\u5bf9\u5e94\u7684\u7d22\u5f15\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u5faa\u73af\u6765\u904d\u5386\u6570\u7ec4<\/strong>\u3002\u9996\u5148\uff0c\u521d\u59cb\u5316\u4e00\u4e2a\u53d8\u91cf\u6765\u5b58\u50a8\u5339\u914d\u7684\u7d22\u5f15\uff0c\u7136\u540e\u901a\u8fc7\u8fed\u4ee3\u6570\u7ec4\u7684\u6bcf\u4e2a\u5143\u7d20\uff0c\u9010\u4e2a\u6bd4\u8f83\u503c\u662f\u5426\u5339\u914d\u3002\u4e00\u65e6\u627e\u5230\u5339\u914d\u7684\u503c\uff0c\u5c06\u7d22\u5f15\u5b58\u50a8\u5728\u53d8\u91cf\u4e2d\u5e76\u7ec8\u6b62\u5faa\u73af\u3002\u5982\u679c\u5faa\u73af\u7ed3\u675f\u540e\u6ca1\u6709\u627e\u5230\u5339\u914d\u7684\u503c\uff0c\u4f60\u53ef\u4ee5\u8fd4\u56de\u4e00\u4e2a\u7279\u5b9a\u7684\u503c\uff0c\u5982 -1\uff0c\u4ee5\u8868\u793a\u67e5\u627e\u5931\u8d25\u3002<\/p>\n<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"\u6570\u7ec4\u5728Java\u4e2d\u662f\u6709\u5e8f\u7684\u5143\u7d20\u96c6\u5408\uff0c\u6570\u7ec4\u4e2d\u7684\u5143\u7d20\u901a\u8fc7\u4e0b\u6807(index)\u8fdb\u884c\u8bbf\u95ee\uff0c\u7d22\u5f15\u503c\u4ece0\u5f00\u59cb\u76f4\u5230\u6570\u7ec4\u957f\u5ea6\u51cf1\u3002 [&hellip;]","protected":false},"author":3,"featured_media":295739,"comment_status":"closed","ping_status":"","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\/295708"}],"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\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=295708"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/295708\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/295739"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=295708"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=295708"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=295708"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}