{"id":138446,"date":"2021-04-26T04:16:53","date_gmt":"2021-04-26T03:16:53","guid":{"rendered":"https:\/\/blog.jetbrains.com\/?post_type=kotlin&#038;p=138446"},"modified":"2021-04-26T04:16:53","modified_gmt":"2021-04-26T03:16:53","slug":"kotlin-1-5-0-rc-released","status":"publish","type":"kotlin","link":"https:\/\/blog.jetbrains.com\/zh-hans\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/","title":{"rendered":"Kotlin 1.5.0-RC \u7248\u672c\u53d1\u5e03\uff1a\u6807\u51c6\u5e93\u548c\u6d4b\u8bd5\u5e93\u7684\u53d8\u66f4"},"content":{"rendered":"<p>Kotlin 1.5.0-RC \u7248\u672c\u5df2\u5177\u5907 1.5.0 \u7248\u672c\u8ba1\u5212\u7684\u6240\u6709\u7279\u6027\u2014\u2014\u8bf7\u67e5\u770b\u5373\u5c06\u53d1\u5e03\u7248\u672c\u7684\u5168\u90e8\u5185\u5bb9\uff01 \u65b0\u7684\u8bed\u8a00\u7279\u6027\uff0c\u6807\u51c6\u5e93\u7684\u66f4\u65b0\uff0c\u6539\u8fdb\u7684\u6d4b\u8bd5\u5e93\u4ee5\u53ca\u8bb8\u591a\u6b63\u5728\u9010\u6b65\u5b8c\u5584\u7684\u6539\u52a8\u3002 \u5728\u6b63\u5f0f\u7248\u53d1\u884c\u4e4b\u524d\u4ec5\u6709\u7684\u6539\u52a8\u5c06\u662f\u95ee\u9898\u4fee\u590d\u3002<\/p>\n<p>\u5728\u60a8\u7684\u9879\u76ee\u4e2d\u5c1d\u8bd5 1.5.0-RC \u7684\u73b0\u4ee3\u5316 Kotlin API\uff0c\u5e76\u5e2e\u52a9\u6211\u4eec\u6539\u5584\u53d1\u884c\u7248\u5427\uff01 \u60a8\u53ef\u4ee5\u5411\u6211\u4eec\u7684\u95ee\u9898\u8ddf\u8e2a\u5668\uff08<a href=\"https:\/\/kotl.in\/issue\" target=\"_blank\" rel=\"noopener\">YouTrack<\/a>\uff09\u62a5\u544a\u6240\u9047\u5230\u7684\u4efb\u4f55\u95ee\u9898\u3002<\/p>\n<p align=\"center\"><a class=\"jb-download-button\" title=\"Install\" href=\"https:\/\/kotlinlang.org\/docs\/install-eap-plugin.html\" target=\"_blank\" rel=\"noopener\">\u5b89\u88c5 1.5.0-RC<\/a><\/p>\n<p>\u5728\u8fd9\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u4eec\u5c06\u5411\u60a8\u4ecb\u7ecd 1.5.0-RC \u4e2d Kotlin \u6807\u51c6\u5e93\u548c\u6d4b\u8bd5\u5e93\u7684\u53d8\u66f4\uff1a<\/p>\n<ul>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#stable-unsigned-integer-types\">\u7a33\u5b9a\u7684\u65e0\u7b26\u53f7\u6574\u578b<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#extensions-for-java-nio-path\">java.nio.file.Path \u6269\u5c55<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#locale-agnostic-upper-lowercase\">\u5b57\u7b26\u4e32\u548c\u5b57\u7b26 API \u7684\u6539\u8fdb<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#duration-api-changes\">Duration API \u7684\u66f4\u6539<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#math-operations-floordiv-mod\">\u65b0\u7684\u6a21\u8fd0\u7b97\u64cd\u4f5c\u7b26<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#collections-firstnotnullof\">\u65b0\u7684\u96c6\u5408\u51fd\u6570<\/a><\/li>\n<li><a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/04\/kotlin-1-5-0-rc-released\/#test-library-changes\">\u6d4b\u8bd5\u5e93\u7684\u53d8\u66f4<\/a><\/li>\n<\/ul>\n<p>\u60a8\u53ef\u4ee5\u5728\u4e0b\u9762\u627e\u5230\u6240\u6709\u8be6\u7ec6\u4fe1\u606f\uff01<\/p>\n<p><a name = \"stable-unsigned-integer-types\"><\/a><\/p>\n<h2>\u7a33\u5b9a\u7684\u65e0\u7b26\u53f7\u6574\u578b<\/h2>\n<p>\u6807\u51c6\u5e93\u4e2d\u5305\u542b\u4e86\u65e0\u7b26\u53f7\u6574\u578b API\uff0c\u53ef\u7528\u4e8e\u5904\u7406\u975e\u8d1f\u6574\u6570\u8fd0\u7b97\u3002\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u65e0\u7b26\u53f7\u7684\u6570\u5b57\u7c7b\u578b\uff1a <code>UInt<\/code>\uff0c <code>ULong<\/code>\uff0c <code>UByte<\/code>\uff0c <code>UShort<\/code>\uff0c\u4ee5\u53ca\u76f8\u5173\u51fd\u6570\uff0c\u4f8b\u5982\u8f6c\u6362\u3002<\/li>\n<li>\u96c6\u5408\u7c7b\u578b\uff1a\u65e0\u7b26\u53f7\u6574\u578b\u7684\u6570\u7ec4\uff0c\u8303\u56f4\u548c\u7ea7\u6570\uff1a  <code>UIntArray<\/code>\uff0c<code>UIntRange<\/code>\uff0c\u4ee5\u53ca\u5176\u4ed6\u7c7b\u578b\u7684\u7c7b\u4f3c\u5bb9\u5668\u3002<\/li>\n<\/ul>\n<p>\u65e0\u7b26\u53f7\u6574\u578b\u4ece <a href=\"https:\/\/kotlinlang.org\/docs\/whatsnew13.html#unsigned-integers\" target=\"_blank\" rel=\"noopener\">Kotlin 1.3<\/a> \u53ef\u4ee5\u4f7f\u7528\u3002 \u73b0\u5728\uff0c\u6211\u4eec\u5c06\u65e0\u7b26\u53f7\u6574\u578b\u548c\u5bf9\u4ed6\u4eec\u7684\u64cd\u4f5c\u5206\u7c7b\u4e3a\u7a33\u5b9a\u7c7b\u578b\uff0c\u4f7f\u5b83\u4eec\u65e0\u9700\u58f0\u660e opt-in \u5373\u53ef\u4f7f\u7528\uff0c\u5e76\u4e14\u53ef\u4ee5\u5728\u5b9e\u9645\u9879\u76ee\u4e2d\u5b89\u5168\u4f7f\u7528\u3002<\/p>\n<p>\u65b0\u7684\u7a33\u5b9a API \u662f\uff1a<\/p>\n<ul>\n<li>\u7a33\u5b9a\u7684\u65e0\u7b26\u53f7\u6574\u578b<\/li>\n<li>\u65e0\u7b26\u53f7\u6574\u578b\u7684\u8303\u56f4\u548c\u7ea7\u6570<\/li>\n<li>\u4f7f\u7528\u65e0\u7b26\u53f7\u6574\u578b\u8fdb\u884c\u8fd0\u7b97\u7684\u51fd\u6570<\/li>\n<\/ul>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    val zero = 0U \/\/ Define unsigned numbers with literal suffixes\r\n    val ten = 10.toUInt() \/\/ or by converting non-negative signed numbers\r\n    \/\/val minusOne: UInt = -1U \/\/ Error: unary minus is not defined\r\n    val range: UIntRange = zero..ten \/\/ Separate types for ranges and progressions\r\n\r\n    for (i in range) print(i)\r\n    println()\r\n    println(&quot;UInt covers the range from ${UInt.MIN_VALUE} to ${UInt.MAX_VALUE}&quot;) \/\/ UInt covers the range from 0 to 4294967295\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p>\u65e0\u7b26\u53f7\u6574\u578b\u6570\u7ec4\u4ecd\u4fdd\u7559\u5728 Beta \u4e2d\u3002 \u7531\u6570\u7ec4\u652f\u6301\u7684\u65e0\u7b26\u53f7\u6574\u6570 <a href=\"https:\/\/kotlinlang.org\/docs\/functions.html#variable-number-of-arguments-varargs\" target=\"_blank\" rel=\"noopener\">varargs<\/a> \u4e5f\u662f\u5982\u6b64\u3002 \u5982\u679c\u8981\u5728\u4ee3\u7801\u4e2d\u4f7f\u7528\u5b83\u4eec\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>@ExperimentalUnsignedTypes<\/code> \u6ce8\u89e3\u9009\u62e9\u52a0\u5165\u3002<\/p>\n<p>\u4e86\u89e3\u66f4\u591a\u6709\u5173 <a href=\"https:\/\/kotlinlang.org\/docs\/basic-types.html#unsigned-integers\" target=\"_blank\" rel=\"noopener\">Kotlin \u65e0\u7b26\u53f7\u6574\u578b<\/a>\u7684\u4fe1\u606f\u3002<\/p>\n<p><a name = \"extensions-for-java-nio-path\"><\/a><\/p>\n<h2>Java.nio.file.Path API \u7684\u6269\u5c55<\/h2>\n<p>Kotlin \u73b0\u5728\u63d0\u4f9b\u4e86\u4e00\u79cd\u901a\u8fc7 <a href=\"https:\/\/docs.oracle.com\/javase\/8\/docs\/api\/java\/nio\/package-summary.html\" target=\"_blank\" rel=\"noopener\">non-blocking Java IO<\/a> \u6269\u5c55\u51fd\u6570\u4ee5Kotlin \u60ef\u7528\u98ce\u683c\u8c03\u7528\u73b0\u4ee3\u7684<a href=\"https:\/\/docs.oracle.com\/javase\/7\/docs\/api\/java\/nio\/file\/Path.html\" target=\"_blank\" rel=\"noopener\"><code>\u65e0\u963b\u585e Java IO<\/code><\/a> \u7684\u65b9\u6cd5\u3002<\/p>\n<p>\u8fd9\u662f\u4e00\u4e2a\u5c0f\u793a\u4f8b\uff1a<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nimport kotlin.io.path.*\r\nimport java.nio.file.Path\r\n\r\nfun main() {\r\n    \/\/ construct path with the div (\/) operator\r\n    val baseDir = Path(&quot;\/base&quot;)\r\n    val subDir = baseDir \/ &quot;subdirectory&quot;\r\n\r\n    \/\/ list files in a directory\r\n    val kotlinFiles = Path(&quot;\/home\/user&quot;).listDirectoryEntries(&quot;*.kt&quot;)\r\n    \/\/ count lines in all kotlin files\r\n    val totalLines = kotlinFiles.sumOf { file -&gt; file.useLines { lines -&gt; lines.count() } }\r\n}\r\n<\/pre>\n<p>\u8fd9\u4e9b\u6269\u5c55\u662f\u5728 <a href=\"https:\/\/kotlinlang.org\/docs\/whatsnew1420.html#extensions-for-java-nio-file-path\" target=\"_blank\" rel=\"noopener\">Kotlin 1.4.20 <\/a>\u4e2d\u4f5c\u4e3a\u5b9e\u9a8c\u529f\u80fd\u5f15\u5165\u7684\uff0c\u73b0\u5728\u65e0\u9700 opt-in \u6ce8\u89e3\u5373\u53ef\u4f7f\u7528\u3002 \u67e5\u770b <a href=\"https:\/\/kotlinlang.org\/api\/latest\/jvm\/stdlib\/kotlin.io.path\/\" target=\"_blank\" rel=\"noopener\"><code>kotlin.io.path<\/code><\/a> \u8f6f\u4ef6\u5305\uff0c\u4ee5\u83b7\u53d6\u53ef\u4ee5\u4f7f\u7528\u7684\u51fd\u6570\u5217\u8868\u3002<\/p>\n<p>File API \u7684\u73b0\u6709\u6269\u5c55\u4ecd\u7136\u53ef\u7528\uff0c\u56e0\u6b64\u4f60\u53ef\u4ee5\u81ea\u7531\u9009\u62e9\u559c\u6b22\u7684API\u3002<\/p>\n<p><a name = \"locale-agnostic-upper-lowercase\"><\/a><\/p>\n<h2>\u4e0e\u8bed\u8a00\u73af\u5883\u65e0\u5173\u7684\u5927\u5199\u548c\u5c0f\u5199\u7684 API<\/h2>\n<p>\u8bb8\u591a\u4eba\u90fd\u719f\u6089\u66f4\u6539\u5b57\u7b26\u4e32\u548c\u5b57\u7b26\u5927\u5c0f\u5199\u7684\u6807\u51c6\u5e93\u51fd\u6570\uff1a <code>toUpperCase()<\/code>\uff0c <code>toLowerCase()<\/code>\uff0c <code>toTitleCase()<\/code> \u3002 \u901a\u5e38\u5b83\u4eec\u53ef\u4ee5\u6b63\u5e38\u5de5\u4f5c\uff0c\u4f46\u662f\u5728\u5904\u7406\u4e0d\u540c\u7684\u5e73\u53f0\u8bed\u8a00\u73af\u5883\u8bbe\u7f6e\u65f6\u4f1a\u8ba9\u4f60\u5934\u75db\u2013\u5b83\u4eec\u90fd\u5bf9\u8bed\u8a00\u73af\u5883\u8bbe\u7f6e\u654f\u611f\uff0c\u8fd9\u610f\u5473\u7740\u5b83\u4eec\u7684\u7ed3\u679c\u53ef\u80fd\u4f1a\u56e0\u8bed\u8a00\u73af\u5883\u8bbe\u7f6e\u800c\u5f02\u3002 \u4f8b\u5982\uff0c<code>&quot;Kotlin&quot;.toUpperCase()<\/code>\u8fd4\u56de\u4ec0\u4e48\uff1f \u4f60\u4f1a\u8bf4\uff1a\u201c\u663e\u7136\u662f<code>KOTLIN<\/code>\u201d\u3002 \u4f46\u662f\u5982\u679c\u4f60\u628a\u8bed\u8a00\u73af\u5883\u8bbe\u7f6e\u4e3a\u571f\u8033\u5176\uff0c\u5927\u5199\u5b57\u6bcd<code>i<\/code>\u662f<code>\u0130<\/code>\uff0c\u56e0\u6b64\u7ed3\u679c\u4f1a\u6709\u6240\u4e0d\u540c\uff1a<code>KOTL\u0130N<\/code>\u3002<\/p>\n<p>\u73b0\u5728\u6709\u4e00\u4e2a\u65b0\u7684\u4e0e\u8bed\u8a00\u73af\u5883\u65e0\u5173\u7684 API\uff0c\u7528\u4e8e\u66f4\u6539\u5b57\u7b26\u4e32\u548c\u5b57\u7b26\u7684\u5927\u5c0f\u5199\uff1a <code>uppercase()<\/code>\uff0c <code>lowercase()<\/code>\uff0c <code>titlecase()<\/code> \u6269\u5c55\u53ca\u5176\u5bf9\u5e94\u7684 <code>* Char()<\/code>\u3002 \u60a8\u53ef\u80fd\u5df2\u7ecf\u5728 <a href=\"https:\/\/kotlinlang.org\/docs\/whatsnew1430.html#locale-agnostic-api-for-upper-lowercasing-text\" target=\"_blank\" rel=\"noopener\">1.4.30<\/a> \u9884\u89c8\u4e2d\u5c1d\u8bd5\u8fc7\u4e86\u3002<\/p>\n<p>\u65e0\u8bba\u5e73\u53f0\u7684\u533a\u57df\u8bbe\u7f6e\u5982\u4f55\uff0c\u65b0\u51fd\u6570\u7684\u8fd4\u56de\u7ed3\u679c\u662f\u76f8\u540c\u7684\u3002 \u53ea\u9700\u8c03\u7528\u8fd9\u4e9b\u51fd\u6570\uff0c\u5176\u4f59\u7684\u7559\u7ed9\u6807\u51c6\u5e93\u3002<\/p>\n<p>\u65e0\u8bba\u5e73\u53f0\u7684\u533a\u57df\u8bbe\u7f6e\u5982\u4f55\uff0c\u65b0\u51fd\u6570\u7684\u8fd4\u56de\u7ed3\u679c\u662f\u76f8\u540c\u7684\u3002<br \/>\n\u53ea\u9700\u8c03\u7528\u8fd9\u4e9b\u51fd\u6570\uff0c\u5176\u4f59\u7684\u7559\u7ed9\u6807\u51c6\u5e93\u3002<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    \/\/ replace the old API\r\n    println(&quot;Kotlin&quot;.toUpperCase()) \/\/ KOTLIN or KOTL\u0130N or?..\r\n\r\n    \/\/ with the new API\r\n    println(&quot;Kotlin&quot;.uppercase()) \/\/ Always KOTLIN\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p>\u5728 JVM \u4e0a\uff0c\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528\u5f53\u524d\u8bed\u8a00\u73af\u5883\u4f5c\u4e3a\u53c2\u6570\u8c03\u7528\u65b0\u51fd\u6570\u6765\u6267\u884c\u5bf9\u8bed\u8a00\u73af\u5883\u654f\u611f\u7684\u5927\u5c0f\u5199\u66f4\u6539\uff1a<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n&quot;Kotlin&quot;.uppercase(Locale.getDefault()) \/\/ Locale-sensitive uppercasing\r\n<\/pre>\n<p>\u65b0\u51fd\u6570\u5c06\u5b8c\u5168\u53d6\u4ee3\u5df2\u7ecf\u5e9f\u5f03\u7684\u65e7\u51fd\u6570\u3002<\/p>\n<h2>\u6e05\u9664\u5b57\u7b26\u5230\u7f16\u7801\u503c\u548c\u5b57\u7b26\u5230\u6570\u5b57\u503c\u7684\u8f6c\u6362<\/h2>\n<p>\u83b7\u53d6\u5b57\u7b26\u7684 UTF-16 \u7f16\u7801\u7684\u64cd\u4f5c<code>-toInt()<\/code>\u51fd\u6570-\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u9677\u9631\uff0c\u56e0\u4e3a\u5b83\u770b\u8d77\u6765\u975e\u5e38\u7c7b\u4f3c\u4e8e\u53ea\u6709\u4e00\u4e2a\u6570\u5b57\u7684\u5b57\u7b26\u4e32\u7684 <code>String.toInt()<\/code> \u64cd\u4f5c\uff0c\u8be5\u64cd\u4f5c\u4ea7\u751f\u4e00\u4e2a\u7531\u8be5\u5b57\u7b26\u4e32\u8868\u793a\u7684 <code>Int<\/code>\u3002<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n&quot;4&quot;.toInt() \/\/ returns 4\r\n&#039;4&#039;.toInt() \/\/ returns 52\r\n<\/pre>\n<p>\u6b64\u5916\uff0c\u6ca1\u6709\u901a\u7528\u51fd\u6570\u4f1a\u4e3a<code>Char &#039;4&#039;<\/code>\u8fd4\u56de\u6570\u5b57\u503c <code>4<\/code> \u3002<\/p>\n<p>\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\uff0c\u73b0\u5728\u63d0\u4f9b\u4e86\u4e00\u7ec4\u65b0\u51fd\u6570\uff0c\u7528\u4e8e\u5728\u5b57\u7b26\u53ca\u6570\u5b57\u7801\u548c\u6570\u5b57\u503c\u4e4b\u95f4\u8fdb\u884c\u8f6c\u6362\uff1a<\/p>\n<ul>\n<li><code>Char(code)<\/code> \u548c <code>Char.code<\/code> \u5728 char \u53ca\u5176\u6570\u5b57\u7801\u4e4b\u95f4\u8f6c\u6362\u3002<\/li>\n<li><code>Char.digitToInt(radix: Int)<\/code> \u548c its <code>*OrNull<\/code> \u4ece\u6307\u5b9a\u57fa\u6570\u7684\u5b57\u7b26\u521b\u5efa\u4e00\u4e2a\u6574\u6570\u3002<\/li>\n<li><code>Int.digitToChar(radix: Int)<\/code> \u4ece\u4e00\u4e2a\u6570\u5b57\u521b\u5efa\u4e00\u4e2a\u5b57\u7b26\uff0c\u8be5\u6570\u5b57\u8868\u793a\u6307\u5b9a\u57fa\u6570\u4e2d\u7684\u6574\u6570\u3002<\/li>\n<\/ul>\n<p>\u8fd9\u4e9b\u51fd\u6570\u5177\u6709\u6e05\u6670\u7684\u540d\u79f0\uff0c\u5e76\u4f7f\u4ee3\u7801\u66f4\u5177\u53ef\u8bfb\u6027\uff1a<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    val capsK = Char(75) \/\/ \u2018K\u2019\r\n    val one = &#039;1&#039;.digitToInt(10) \/\/ 1\r\n    val digitC = 12.digitToChar(16) \/\/ hexadecimal digit \u2018C\u2019\r\n\r\n    println(&quot;${capsK}otlin ${one}.5.0-R${digitC}&quot;) \/\/ \u201cKotlin 1.5.0-RC\u201d\r\n    println(capsK.code) \/\/ 75\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p>\u4ece <a href=\"https:\/\/kotlinlang.org\/docs\/whatsnew1430.html#clear-char-to-code-and-char-to-digit-conversions\" target=\"_blank\" rel=\"noopener\">Kotlin 1.4.30<\/a>  \u5f00\u59cb\u9884\u89c8\u6a21\u5f0f\u4e0b\u53ef\u7528\u7684\u65b0\u51fd\u6570\u73b0\u5df2\u7a33\u5b9a\u3002 \u5b57\u7b26\u5230\u6570\u5b57\u8f6c\u6362\u7684\u65e7\u51fd\u6570\uff08 <code>Char.toInt()<\/code>\u548c\u5176\u4ed6\u6570\u5b57\u7c7b\u578b\u7684\u76f8\u4f3c\u51fd\u6570\uff09\u548c\u6570\u5b57\u5230\u5b57\u7b26\u8f6c\u6362\uff08<code>Long.toChar()<\/code>\u548c\u7c7b\u4f3c\u7684\u5b57\u7b26\uff0c\u4f46<code>Int.toChar()<\/code>\u9664\u5916\uff09\u7684\u65e7\u51fd\u6570\u73b0\u5728\u5df2\u7ecf\u5e9f\u5f03\u3002<\/p>\n<h2>Char API\u7684\u591a\u5e73\u53f0\u6269\u5c55\u65b9\u6cd5<\/h2>\n<p>\u6211\u4eec\u5c06\u7ee7\u7eed\u6269\u5c55\u6807\u51c6\u5e93\u7684\u8de8\u5e73\u53f0\u90e8\u5206\uff0c\u4ee5\u5c06\u5176\u6240\u6709\u529f\u80fd\u63d0\u4f9b\u7ed9\u8de8\u5e73\u53f0\u9879\u76ee\u7684\u901a\u7528\u4ee3\u7801\u3002<br \/>\n\u73b0\u5728\u6211\u4eec\u5df2\u7ecf\u5411\u5168\u5e73\u53f0\u4ee5\u53ca\u901a\u7528\u4ee3\u7801\u63d0\u4f9b\u5927\u90e8\u5206\u7684 <code>Char<\/code>\u51fd\u6570\u4e86\u3002 \u8fd9\u4e9b\u51fd\u6570\u5305\u62ec:<\/p>\n<ul>\n<li>\u68c0\u67e5\u4e00\u4e2a\u5b57\u7b26\u662f\u5b57\u6bcd\u8fd8\u662f\u6570\u5b57\u7684 <code>Char.isDigit()<\/code>, <code>Char.isLetter()<\/code>, <code>Char.isLetterOrDigit()<\/code> \u3002<\/li>\n<li>\u68c0\u67e5\u5b57\u7b26\u5927\u5c0f\u5199\u7684 <code>Char.isLowerCase()<\/code>, <code>Char.isUpperCase()<\/code>, <code>Char.isTitleCase()<\/code> \u3002<\/li>\n<li>\u68c0\u67e5\u5b57\u7b26\u662f\u5426\u542b\u6709<code>Cn<\/code> (<em>\u672a\u5b9a\u4e49<\/em>)\u4ee5\u5916 <a href=\"https:\/\/unicode.org\/reports\/tr44\/#General_Category_Values\" target=\"_blank\" rel=\"noopener\">Unicode \u901a\u7528\u7c7b\u522b<\/a>\u7684<code>Char.isDefined()<\/code>\u3002<\/li>\n<li>\u68c0\u67e5\u5b57\u7b26\u662f\u5426\u4e3a <a href=\"https:\/\/en.wikipedia.org\/wiki\/Control_character\" target=\"_blank\" rel=\"noopener\">ISO \u63a7\u5236\u5b57\u7b26<\/a>\u7684<code>Char.isISOControl()<\/code>\uff0c\u5176\u5b57\u8282\u7f16\u7801\u8303\u56f4\u4e3a <code>\\u0000<\/code>..<code>\\u001F<\/code> or <code>\\u007F<\/code>..<code>\\u009F<\/code>\u3002<\/li>\n<\/ul>\n<p><code>Char.category<\/code>\u5c5e\u6027\u53ca\u5176\u8fd4\u56de\u7684\u679a\u4e3e\u7c7b\u578b<code>CharCategory<\/code>\uff08\u6839\u636eUnicode\u6307\u793a\u5b57\u7b26\u7684\u901a\u7528\u7c7b\u578b\uff09\u73b0\u53ef\u5728\u8de8\u5e73\u53f0\u9879\u76ee\u8bbf\u95ee\u3002<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    val array = &quot;Kotlin 1.5.0-RC&quot;.toCharArray()\r\n    val (letterOrDigit, punctuation) = array.partition { it.isLetterOrDigit() }\r\n    val (upperCase, notUpperCase ) = array.partition { it.isUpperCase() }\r\n\r\n    println(&quot;$letterOrDigit, $punctuation&quot;) \/\/ [K, o, t, l, i, n, 1, 5, 0, R, C], [ , ., ., -]\r\n    println(&quot;$upperCase, $notUpperCase&quot;) \/\/ [K, R, C], [o, t, l, i, n, , 1, ., 5, ., 0, -]\r\n\r\n    if (array[0].isDefined()) println(array[0].category)\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<h2>\u7cbe\u786e\u7248\u672c\u7684 String?.toBoolean()<\/h2>\n<p>Kotlin\u7684<code>String?.toBoolean()<\/code>\u51fd\u6570\u5e7f\u6cdb\u7528\u4e8e\u901a\u8fc7\u5b57\u7b26\u4e32\u521b\u5efa\u5e03\u5c14\u503c\u3002 \u5b83\u7684\u5de5\u4f5c\u539f\u7406\u975e\u5e38\u7b80\u5355: \u4e0d\u8bba\u5927\u5c0f\u5199\uff0c\u5728&quot;true&quot;\u5b57\u7b26\u4e32\u4e0a\u90fd\u4e3a<code>true<\/code>\uff0c\u800c\u5176\u4ed6\u5b57\u6240\u6709\u7b26\u4e32\uff08\u5305\u62ec<code>null<\/code>\uff09\u4e0a\u90fd\u4e3a<code>false<\/code>\u3002<\/p>\n<p>\u867d\u7136\u8fd9\u79cd\u8868\u73b0\u770b\u8d77\u6765\u5f88\u81ea\u7136\uff0c\u4f46\u5b83\u9690\u85cf\u4e86\u6f5c\u5728\u7684\u5f02\u5e38\u60c5\u51b5\u3002 \u901a\u8fc7\u8be5\u51fd\u6570\u7684\u8f6c\u6362\uff0c\u65e0\u8bba\u5b57\u7b26\u4e32\u5177\u6709\u54ea\u4e9b\u975e\u5e38\u89c4\u7684\u503c\uff0c\u4f60\u90fd\u5c06\u5f97\u5230\u4e00\u4e2a\u5e03\u5c14\u503c\u3002<\/p>\n<p><a href=\"https:\/\/kotlinlang.org\/api\/latest\/jvm\/stdlib\/kotlin.text\/to-boolean.html\" target=\"_blank\" rel=\"noopener\">String?.toBoolean()<\/a> \u65b0\u7684\u533a\u5206\u5927\u5c0f\u5199\u7684\u4e25\u683c\u7248\u672c\u6709\u52a9\u4e8e\u907f\u514d\u6b64\u7c7b\u9519\u8bef\uff1a<\/p>\n<ul>\n<li><code>String.toBooleanStrict()<\/code> \u4f1a\u5bf9\u9664\u201ctrue\u201d\u548c\u201cfalse\u201d\u4ee5\u5916\u7684\u6240\u6709\u8f93\u5165\u629b\u51fa\u5f02\u5e38\u3002<\/li>\n<li><code>String.toBooleanStrictOrNull()<\/code> \u4f1a\u5bf9\u9664\u201ctrue\u201d\u548c\u201cfalse\u201d\u4ee5\u5916\u7684\u6240\u6709\u8f93\u5165\u90fd\u8fd4\u56de <code>null<\/code>\u3002<\/li>\n<\/ul>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    println(&quot;true&quot;.toBooleanStrict()) \/\/ True\r\n    \/\/ println(&quot;1&quot;.toBooleanStrict()) \/\/ Exception\r\n    println(&quot;1&quot;.toBooleanStrictOrNull()) \/\/ null\r\n    println(&quot;True&quot;.toBooleanStrictOrNull()) \/\/ null: the function is case-sensitive\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p><a name = \"duration-api-changes\"><\/a><\/p>\n<h2>Duration API \u7684\u66f4\u6539<\/h2>\n<p>\u4ece1.3.50\u7248\u5f00\u59cb\u7684\u5b9e\u9a8c\u6027<a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2019\/08\/kotlin-1-3-50-released\/#time-measurement-api\">\u6301\u7eed\u65f6\u95f4\u548c\u65f6\u95f4\u6d4b\u91cfAPI <\/a> \u5df2\u5728stdlib\u4e2d\u63d0\u4f9b\u3002 \u63d0\u4f9b\u4e86\u7528\u4e8e\u7cbe\u786e\u6d4b\u91cf\u65f6\u95f4\u95f4\u9694\u7684API\u3002<\/p>\n<p>\u8fd9\u4e9bAPI\u7684\u5176\u4e2d\u4e00\u4e2a\u5173\u952e\u7c7b\u662f <a href=\"https:\/\/kotlinlang.org\/api\/latest\/jvm\/stdlib\/kotlin.time\/-duration\/\" target=\"_blank\" rel=\"noopener\"><code>Duration<\/code><\/a>\u3002 \u5b83\u8868\u793a\u4e24\u4e2a\u65f6\u523b\u4e4b\u95f4\u7684\u65f6\u95f4\u957f\u5ea6\u3002 \u57281.5.0\uff0cDuration\u5176API\u548c\u5185\u90e8\u5f62\u5f0f\u53d1\u751f\u4e86\u91cd\u5927\u53d8\u5316\u3002<\/p>\n<p><code>Duration<\/code> \u5176\u5185\u90e8\u73b0\u5728\u4f7f\u7528<code>Long<\/code>\u503c\u7c7b\u578b\u4ee3\u66ff\u4e86<code>Double<\/code>\u3002 <code>Long<\/code>\u503c\u7684\u8868\u793a\u8303\u56f4\u76f8\u5f53\u4e8e\u7eb3\u79d2\u7ea7\u7684\u4e00\u767e\u591a\u5e74\u6216\u6beb\u79d2\u7ea7\u7684\u4e00\u4ebf\u5e74\u3002 \u4f46\u662f\uff0c\u6b64\u524d\u7684\u4e9a\u7eb3\u79d2\u7ea7\u6301\u7eed\u65f6\u95f4\u5df2\u4e0d\u518d\u652f\u6301\u3002<\/p>\n<p>\u6211\u4eec\u8fd8\u5f15\u5165\u4e86\u65b0\u7684\u5c5e\u6027\u503c\uff0c\u7528\u4e8e\u83b7\u53d6<code>duration<\/code>\u7684<code>Long<\/code>\u503c\u3002 \u5b83\u4eec\u53ef\u7528\u4e8e\u5404\u79cd\u65f6\u95f4\u5355\u4f4d\uff1a<code>Duration.inWholeMinutes<\/code>\uff0c<code>Duration.inWholeSeconds<\/code>\u7b49\u3002 \u8fd9\u4e9b\u51fd\u6570\u7528\u6765\u66ff\u6362\u57fa\u4e8e<code>Double<\/code>\u7684\u5c5e\u6027\uff0c\u4f8b\u5982<code>Duration.inMinutes<\/code>\u3002<\/p>\n<p>\u53e6\u4e00\u4e2a\u6539\u52a8\u662f\u4e00\u7ec4\u65b0\u7684\u5de5\u5382\u51fd\u6570\uff0c\u7528\u4e8e\u901a\u8fc7\u6574\u6570\u521b\u5efa<code>Duration<\/code>\u5b9e\u4f8b\u3002 \u5b83\u4eec\u76f4\u63a5\u5b9a\u4e49\u5728<code>Duration<\/code>\u7c7b\u578b\u4e2d\uff0c\u4ee5\u66ff\u6362\u6570\u5b57\u7c7b\u578b\u7684\u65e7\u6269\u5c55\u5c5e\u6027\uff0c\u4f8b\u5982<code>Int.seconds<\/code>\u3002<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nimport kotlin.time.ExperimentalTime\r\nimport kotlin.time.Duration\r\n\r\n@ExperimentalTime\r\nfun main() {\r\n    val duration = Duration.milliseconds(120000)\r\n    println(&quot;There are ${duration.inWholeSeconds} seconds in ${duration.inWholeMinutes} minutes&quot;)\r\n}\r\n<\/pre>\n<p>\u7531\u4e8e\u8fd9\u4e9b\u91cd\u5927\u66f4\u6539\uff0c\u6240\u6709\u6301\u7eed\u65f6\u95f4\u548c\u65f6\u95f4\u6d4b\u91cf\u7684API\u57281.5.0\u4e2d\u4ecd\u5904\u4e8e\u8bd5\u9a8c\u9636\u6bb5\uff0c\u9700\u8981<code>@ExperimentalTime<\/code>\u6ce8\u91ca\u6765\u9009\u62e9\u6027\u5f15\u5165\u3002<\/p>\n<p>\u8bf7\u5c1d\u8bd5\u65b0\u7684\u7248\u672c\uff0c\u5e76\u5728\u6211\u4eec\u7684\u95ee\u9898\u8ddf\u8e2a\u5668 <a href=\"https:\/\/kotl.in\/issue\" target=\"_blank\" rel=\"noopener\">YouTrack<\/a> \u4e2d\u5206\u4eab\u4f60\u7684\u53cd\u9988\u3002<\/p>\n<p><a name = \"math-operations-floordiv-mod\"><\/a><\/p>\n<h2>\u6570\u5b66\u8fd0\u7b97: \u5411\u4e0b\u53d6\u6574\u548c\u6c42\u4f59\u8fd0\u7b97\u7b26<\/h2>\n<p>\u5728Kotlin\u4e2d\uff0c<a href=\"https:\/\/kotlinlang.org\/docs\/basic-types.html#operations\" target=\"_blank\" rel=\"noopener\">\u6574\u6570\u7684\u9664\u6cd5\u8fd0\u7b97\u7b26 (<code>\/<\/code>) <\/a> \u8868\u793a<em>\u622a\u65ad\u9664\u6cd5<\/em>\uff0c\u5b83\u53bb\u6389\u4e86\u7ed3\u679c\u7684\u5c0f\u6570\u90e8\u5206\u3002 \u5728\u6a21\u8fd0\u7b97\u4e2d\uff0c\u8fd8\u6709\u53e6\u4e00\u79cd\u9009\u62e9<em>\u5411\u4e0b\u53d6\u6574\u9664\u6cd5<\/em>\uff0c\u5176\u7ed3\u679c\u5c06\u5411\u4e0b\u53d6\u6574 (\u671d\u8f83\u5c0f\u7684\u6574\u6570\u65b9\u5411) \uff0c\u4ece\u800c\u5bf9\u8d1f\u6570\u4f1a\u4ea7\u751f\u4e0d\u540c\u7684\u7ed3\u679c\u3002<\/p>\n<p>\u5728\u4e4b\u524d\uff0c\u5411\u4e0b\u53d6\u6574\u9664\u6cd5\u5c06\u8981\u6c42\u4f20\u9012\u4e00\u4e2a\u81ea\u5b9a\u4e49\u51fd\u6570\uff0c\u5982:<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun floorDivision(i: Int, j: Int): Int {\r\n    var result = i \/ j\r\n    if (i != 0 &amp;&amp; result &lt;= 0) result--\r\n    return result\r\n}\r\n<\/pre>\n<p>\u57281.5.0-RC\uff0c\u6211\u4eec\u5f15\u5165\u4e86<code>codefloorDiv()<\/code>\u51fd\u6570\uff0c\u8be5\u51fd\u6570\u5c06\u5bf9\u6574\u6570\u8fdb\u884c\u5411\u4e0b\u53d6\u6574\u8fd0\u7b97\u3002<code>floorDiv()<\/code>\u51fd\u6570\uff0c\u8be5\u51fd\u6570\u5c06\u5bf9\u6574\u6570\u8fdb\u884c\u5411\u4e0b\u53d6\u6574\u8fd0\u7b97\u3002<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    println(&quot;Truncated division -5\/3: ${-5 \/ 3}&quot;)\r\n    println(&quot;Floored division -5\/3: ${(-5).floorDiv(3)}&quot;)\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p>\u57281.5.0\uff0c\u6211\u4eec\u5f15\u5165\u4e86\u65b0\u7684<code>mod()<\/code>\u51fd\u6570\u3002 \u73b0\u5728\uff0c\u5b83\u7684\u529f\u80fd\u5b8c\u5168\u7b26\u5408\u5176\u540d\u79f0\u2013-\u5b83\u8fd4\u56de<em>\u6a21\u6570<\/em>\uff0c\u5373\u5411\u4e0b\u53d6\u6574\u9664\u6cd5\u7684\u4f59\u6570\u90e8\u5206\u3002<\/p>\n<p>\u5b83\u4e0d\u540c\u4e8eKotlin\u7684<code>rem()<\/code> (\u6216<code>%<\/code>\u8fd0\u7b97\u7b26) \u3002 \u6a21\u6570\u662f<code>a<\/code>\u548c<code>a.floorDiv(b)* b<\/code>\u7684\u5dee\u3002 \u975e\u96f6\u6a21\u6570\u59cb\u7ec8\u4e0e<code>b<\/code>\u5177\u6709\u76f8\u540c\u7684\u7b26\u53f7\uff0c\u800c<code>a\uff05b<\/code>\u53ef\u4ee5\u6709\u4e0d\u540c\u7684\u7b26\u53f7\u3002 \u4f8b\u5982\uff0c\u5728\u5b9e\u73b0\u5faa\u73af\u5217\u8868\u65f6\uff0c\u8fd9\u53ef\u80fd\u4f1a\u5f88\u6709\u7528\uff1a<\/p>\n<pre class=\"kotlin-code\" data-version=\"1.5.0-RC\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nfun main() {\r\n\/\/sampleStart\r\n    fun getNextIndexCyclic(current: Int, size: Int ) = (current + 1).mod(size)\r\n    fun getPreviousIndexCyclic(current: Int, size: Int ) = (current - 1).mod(size)\r\n    \/\/ unlike %, mod() produces the expected non-negative value even if (current - 1) is less than 0\r\n\r\n    val size = 5\r\n    for (i in 0..(size * 2)) print(getNextIndexCyclic(i, size))\r\n    println()\r\n    for (i in 0..(size * 2)) print(getPreviousIndexCyclic(i, size))\r\n\/\/sampleEnd\r\n}\r\n<\/pre>\n<p><a name = \"collections-firstnotnullof\"><\/a><\/p>\n<h2>\u96c6\u5408\uff1a firstNotNullOf() and firstNotNullOfOrNull()<\/h2>\n<p>Kotlin\u96c6\u5408API\u901a\u8fc7\u5185\u7f6e\u51fd\u6570\u8986\u76d6\u4e86\u4e00\u7cfb\u5217\u9488\u5bf9\u96c6\u5408\u7684\u6d41\u884c\u64cd\u4f5c\u3002 \u5bf9\u4e8e\u4e0d\u5e38\u89c1\u7684\u6848\u4f8b\uff0c\u901a\u5e38\u5c06\u8fd9\u4e9b\u51fd\u6570\u8c03\u7528\u7ed3\u5408\u5230\u4e00\u8d77\u3002 \u5c3d\u7ba1\u5b83\u80fd\u5b8c\u6210\u4efb\u52a1\uff0c\u4f46\u901a\u5e38\u6765\u8bf4\u770b\u8d77\u6765\u5e76\u4e0d\u4f18\u96c5\uff0c\u800c\u4e14\u53ef\u80fd\u4f1a\u5bfc\u81f4\u989d\u5916\u7684\u5f00\u9500\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u8981\u901a\u8fc7\u9009\u62e9\u5668\u51fd\u6570\u83b7\u53d6\u96c6\u5408\u7684\u7b2c\u4e00\u4e2a\u975e\u7a7a\u7ed3\u679c\uff0c\u53ef\u4ee5\u8c03\u7528<code>mapNotNull()<\/code>\u548c<code>first()<\/code>\u3002 \u57281.5.0\uff0c\u901a\u8fc7\u65b0\u51fd\u6570<code>firstNotNullOf()<\/code>\uff0c\u4f60\u53ea\u9700\u8981\u4e00\u6b21\u8c03\u7528\u4fbf\u80fd\u505a\u5230\u3002 \u6211\u4eec\u4e0e<code>firstNotNullOf()<\/code>\u4e00\u540c\u6dfb\u52a0\u4e86\u5b83\u5bf9\u5e94\u7684<code>*orNull()<\/code>\u51fd\u6570\uff0c\u5982\u679c\u6ca1\u6709\u8fd4\u56de\u503c\uff0c\u5c06\u8fd4null\u3002<\/p>\n<p>\u4ee5\u4e0b\u662f\u4ee3\u7801\u7b80\u6d01\u540e\u7684\u793a\u4f8b\u3002<\/p>\n<p>\u5047\u8bbe\u4f60\u7684\u7c7b\u6709\u4e00\u4e2a\u53ef\u7a7a\u5c5e\u6027\uff0c\u540c\u65f6\u4f60\u9700\u8981\u83b7\u53d6\u7c7b\u5b9e\u4f8b\u6570\u7ec4\u4e2d\u7684\u7b2c\u4e00\u4e2a\u975e\u7a7a\u503c\u3002<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nclass Item(val name: String?)\r\n<\/pre>\n<p>\u4f60\u53ef\u4ee5\u901a\u8fc7\u8fed\u4ee3\u96c6\u5408\u5e76\u68c0\u67e5\u5c5e\u6027\u662f\u5426\u4e3a\u975enull\u6765\u5b9e\u73b0\uff1a<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n\/\/ Option 1: manual implementation\r\nfor (element in collection) {\r\n    val itemName = element.name\r\n    if (itemName != null) return itemName\r\n}\r\nreturn null\r\n<\/pre>\n<p>\u53e6\u4e00\u79cd\u65b9\u5f0f\u662f\u4f7f\u7528\u65e7\u51fd\u6570<code>mapNotNull()<\/code>\u548c<code>firstOrNull()<\/code>\u3002 \u8bf7\u6ce8\u610f\uff0c <code>mapNotNull()<\/code>\u4f1a\u521b\u5efa\u4e00\u4e2a\u4e2d\u95f4\u96c6\u5408\uff0c\u5c24\u5176\u662f\u5bf9\u4e8e\u5927\u578b\u96c6\u5408\uff0c\u8fd9\u4f1a\u6d88\u8017\u989d\u5916\u7684\u5185\u5b58\u3002 \u56e0\u6b64\uff0c\u8fd9\u91cc\u53ef\u80fd\u9700\u8981\u8f6c\u6362\u4e3a\u5e8f\u5217\u3002<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n\/\/ Option 2: old stdlib functions\r\nreturn collection\r\n    \/\/ .asSequence() \/\/ Avoid creating intermediate list for big collections\r\n    .mapNotNull { it.name }\r\n    .firstOrNull()\r\n<\/pre>\n<p>\u8fd9\u5c31\u662f\u65b0\u51fd\u6570\u770b\u8d77\u6765\u7684\u6837\u5b50:<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n\/\/ Option 3: new firstNotNullOfOrNull()\r\nreturn collection.firstNotNullOfOrNull { it.name }\r\n<\/pre>\n<p><a name = \"test-library-changes\"><\/a><\/p>\n<h2>\u6d4b\u8bd5\u5e93\u7684\u53d8\u66f4<\/h2>\n<p>\u6211\u4eec\u5df2\u6709\u51e0\u4e2a\u6b63\u5f0f\u7248\u6ca1\u6709\u53d1\u5e03 Kotlin \u6d4b\u8bd5\u5e93 <code>kotlin-test<\/code>\u7684\u91cd\u8981\u66f4\u65b0\u4e86\uff0c\u800c\u73b0\u5728\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u4e9b\u671f\u5f85\u5df2\u4e45\u7684\u6539\u52a8\u3002 \u57281.5.0-RC\uff0c\u4f60\u53ef\u4ee5\u5c1d\u8bd5\u8bb8\u591a\u65b0\u7279\u6027\uff1a<\/p>\n<ul>\n<li>\u5728\u591a\u5e73\u53f0\u9879\u76ee\u91cc\u53ea\u9700\u8981\u5bf9<code>codekotlin-test<\/code>do\u5355\u6b21\u4f9d\u8d56\u3002>kotlin-test`\u5355\u6b21\u4f9d\u8d56\u3002<\/li>\n<li>\u81ea\u52a8\u4e3aKotlin\/JVM\u6e90\u96c6\u9009\u62e9\u6d4b\u8bd5\u6846\u67b6\u3002<\/li>\n<li>\u65ad\u8a00\u51fd\u6570\u7684\u66f4\u65b0\u3002<\/li>\n<\/ul>\n<h3>\u591a\u5e73\u53f0\u9879\u76ee\u4e2d\u7684kotlin-test\u4f9d\u8d56<\/h3>\n<p>\u6211\u4eec\u4ecd\u6301\u7eed\u591a\u5e73\u53f0\u9879\u76ee\u914d\u7f6e\u6d41\u7a0b\u7684\u5f00\u53d1\u3002 \u57281.5.0\uff0c\u6211\u4eec\u8ba9\u6240\u6709\u6e90\u96c6\u66f4\u52a0\u6613\u4e8e\u521b\u5efa\u5bf9<code>kotlin-test<\/code>\u7684\u4f9d\u8d56\u3002<\/p>\n<p>\u73b0\u5728\uff0c\u4f60\u4ec5\u4ec5\u9700\u8981\u5728\u901a\u7528\u6d4b\u8bd5\u6e90\u96c6\u4e2d\u6dfb\u52a0<code>kotlin-test<\/code>\u4f9d\u8d56\u9879\u3002 Gradle\u63d2\u4ef6\u5c06\u4e3a\u5176\u4ed6\u6e90\u96c6\u63a8\u65ad\u51fa\u5e73\u53f0\u5bf9\u5e94\u7684\u4f9d\u8d56\uff1a<\/p>\n<ul>\n<li>\u5bf9\u4e8eJVM\u6e90\u96c6\u5219\u662f<code>kotlin-test-junit<\/code>\u3002 \u4f60\u53ef\u4ee5\u663e\u5f0f\u6307\u5b9a\u5207\u6362\u5230<code>kotlin-test-junit-5<\/code>\u6216<code>kotlin-test-testng<\/code>(\u7ee7\u7eed\u9605\u8bfb\u4e86\u89e3\u5177\u4f53\u65b9\u6cd5)\u3002<\/li>\n<li>\u5bf9\u4e8e Kotlin\/JS \u6e90\u96c6\u5219\u662f<code>kotlin-test-js<\/code>\u3002<\/li>\n<li>\u5bf9\u4e8e\u901a\u7528\u6e90\u96c6\u5219\u662f <code>kotlin-test-common<\/code> \u548c <code>kotlin-test-annotations-common<\/code>\u3002<\/li>\n<li>Kotlin\/Native\u6e90\u96c6\u6ca1\u6709\u591a\u4f59\u7684\u5de5\u4ef6\uff0c\u56e0\u4e3aKotlin\/Native\u63d0\u4f9b\u4e86<code>kotlin-testAPI\u7684\u5185\u7f6e\u5b9e\u73b0\u3002<\/code><\/li>\n<\/ul>\n<h3>\u4e3aKotlin\/JVM\u6e90\u96c6\u81ea\u52a8\u9009\u62e9\u6d4b\u8bd5\u6846\u67b6<\/h3>\n<p>\u5982\u4e0a\u6240\u8ff0\uff0c\u4e00\u65e6\u5728\u901a\u7528\u6d4b\u8bd5\u6e90\u96c6\u4e2d\u6307\u5b9a\u4e86<code>kotlin-test<\/code>\u7684\u4f9d\u8d56\uff0c JVM \u6e90\u96c6\u5c31\u4f1a\u81ea\u52a8\u521b\u5efa\u5bf9<code>JUnit 4<\/code>\u7684\u4f9d\u8d56\u3002<\/p>\n<p>\u5728Groovy DSL\u4e0a\u770b\u8d77\u6765\u662f\u8fd9\u6837\u7684:<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nkotlin {\r\n    sourceSets {\r\n        commonTest {\r\n            dependencies {\r\n                 \/\/ This brings the dependency\r\n                \/\/ on JUnit 4 transitively\r\n                implementation kotlin(&#039;test&#039;)\r\n            }\r\n        }\r\n    }\r\n}\r\n<\/pre>\n<\/p>\n<p>\u800c\u5728Kotlin DSL\u5219\u662f\u5982\u6b64:<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nkotlin {\r\n    sourceSets {\r\n        val commonTest by getting {\r\n            dependencies {\r\n                \/\/ This brings the dependency\r\n                \/\/ on JUnit 4 transitively\r\n                implementation(kotlin(&quot;test&quot;))\r\n            }\r\n        }\r\n    }\r\n}\r\n<\/pre>\n<p>\u4f60\u8fd8\u53ef\u4ee5\u5728\u6d4b\u8bd5\u4efb\u52a1\u4e2d\u7b80\u5355\u5730\u901a\u8fc7\u4e00\u4e2a\u51fd\u6570\u6765\u5207\u6362\u5230JUnit 5\u6216TestNG\uff1a<a href=\"https:\/\/docs.gradle.org\/current\/javadoc\/org\/gradle\/api\/tasks\/testing\/Test.html#useJUnitPlatform--\" target=\"_blank\" rel=\"noopener\"><code>useJUnitPlatform()<\/code><\/a>\u6216 <a href=\"https:\/\/docs.gradle.org\/current\/javadoc\/org\/gradle\/api\/tasks\/testing\/Test.html#useTestNG--\" target=\"_blank\" rel=\"noopener\"><code>useTestNG()<\/code><\/a>\u3002<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\nkotlin {\r\n    jvm {\r\n        testRuns[&quot;test&quot;].executionTask.configure {\r\n            \/\/ enable TestNG support\r\n            useTestNG()\r\n            \/\/ or\r\n            \/\/ enable JUnit Platform (a.k.a. JUnit 5) support\r\n            useJUnitPlatform()\r\n        }\r\n    }\r\n}\r\n<\/pre>\n<p>\u5f53\u4f60\u5728\u4ec5\u9762\u5411JVM\u7684\u9879\u76ee\u4e2d\u6dfb\u52a0<code>kotlin-test<\/code>\u4f9d\u8d56\u65f6\u4e5f\u662f\u5982\u6b64\u3002<\/p>\n<h3>\u65ad\u8a00\u51fd\u6570\u7684\u66f4\u65b0<\/h3>\n<p>\u57281.5.0\uff0c\u6211\u4eec\u51c6\u5907\u4e86\u8bb8\u591a\u65b0\u7684\u65ad\u8a00\u51fd\u6570\uff0c\u4ee5\u53ca\u5bf9\u73b0\u6709\u65ad\u8a00\u51fd\u6570\u7684\u6539\u8fdb\u3002<\/p>\n<p>\u9996\u5148\uff0c\u6211\u4eec\u6765\u5feb\u901f\u6d4f\u89c8\u4e0b\u65b0\u7684\u51fd\u6570:<\/p>\n<ul>\n<li>\u7528\u4e8e\u68c0\u67e5\u65f6\u901f\u5c40\u7c7b\u578b\u7684<code>assertIs&lt;T&gt;()<\/code> \u548c <code>assertIsNot&lt;T&gt;()<\/code>\u3002<\/li>\n<li>\u7528\u4e8e\u6bd4\u8f83\u6570\u7ec4\u3001\u5e8f\u5217\u4ee5\u53ca\u6240\u6709<code>Iterable<\/code>\u5185\u5bb9\u7684 <code>assertContentEquals()<\/code>\u3002 \u66f4\u51c6\u786e\u5730\u8bf4\uff0c\u5b83\u68c0\u67e5\u9884\u671f\u548c\u5b9e\u9645\u7684\u5143\u7d20\u53ca\u5176\u987a\u5e8f\u662f\u5426\u4e00\u81f4\u3002<\/li>\n<li><code>Double<\/code>\u548c<code>Float<\/code>\u7684<code>assertEquals()<\/code>\u548c<code>assertNotEquals()<\/code>\u6709\u65b0\u7684\u91cd\u8f7d\uff0c\u5e76\u5e26\u6709\u7b2c\u4e09\u4e2a\u53c2\u6570\u2013\u7cbe\u5ea6\u3002<\/li>\n<li>\u68c0\u67e5\u6570\u7ec4\u3001\u5217\u8868\u3001\u8303\u56f4\u7b49\u662f\u5426<code>contains()<\/code>\u6307\u5b9a<code>object<\/code>\u7684<code>assertContains()<\/code>\u3002<\/li>\n<\/ul>\n<p>\u4ee5\u4e0b\u662f\u4e00\u4e2a\u7b80\u77ed\u7684\u793a\u4f8b\uff0c\u5c55\u793a\u4e86\u8fd9\u4e9b\u51fd\u6570\u7684\u7528\u6cd5\uff1a<\/p>\n<pre class=\"kotlin-code\" data-highlight-only=\"true\" theme=\"idea\" indent=\"4\" style=\"visibility: hidden; padding: 36px 0;\">\r\n@Test\r\nfun test() {\r\n    val expectedArray = arrayOf(1, 2, 3)\r\n    val actualArray = Array(3) { it + 1 }\r\n    \r\n    val first: Any = actualArray[0]\r\n    assertIs&lt;Int&gt;(first)\r\n    \/\/ first is smart-cast to Int now\r\n    println(&quot;${first + 1}&quot;)\r\n    \r\n    assertContentEquals(expectedArray, actualArray)\r\n    assertContains(expectedArray, 2)\r\n\r\n    val x = sin(PI)\r\n\r\n    \/\/ precision parameter\r\n    val tolerance = 0.000001\r\n\r\n    assertEquals(0.0, x, tolerance)\r\n}\r\n<\/pre>\n<p>\u5bf9\u4e8e\u73b0\u6709\u7684\u65ad\u8a00\u51fd\u6570\u2014\u2014\u73b0\u5728\u53ef\u4ee5\u5728<code>assertTrue()<\/code>\uff0c<code>assertFalse()<\/code>\u7684<code>lambda<\/code>\u53c2\u6570\u5185\u8c03\u7528 <a href=\"https:\/\/kotlinlang.org\/docs\/composing-suspending-functions.html\" target=\"_blank\" rel=\"noopener\">suspending functions<\/a> \u4e86\uff0c\u4ee5\u53caexpect()\uff0c\u56e0\u4e3a\u8fd9\u4e9b\u51fd\u6570\u73b0\u5728\u662f<a href=\"https:\/\/kotlinlang.org\/docs\/inline-functions.html\" target=\"_blank\" rel=\"noopener\"> \u5185\u8054 <\/a>\u7684\u3002<\/p>\n<h2>\u5c1d\u8bd5 Kotlin 1.5.0\u7684\u6240\u6709\u7279\u6027 <\/h2>\n<p>\u8ba9 1.5.0-RC \u4e3a\u60a8\u7684\u9879\u76ee\u5f15\u5165\u73b0\u4ee3\u5316\u7684 Kotlin API!<\/p>\n<p>\u5728 IntelliJ IDEA \u6216 Android Studio \u5b89\u88c5 1.5.0-RC \u7684 Kotlin \u63d2\u4ef6\u3002 \u4e86\u89e3\u5982\u4f55\u83b7\u53d6<a href=\"https:\/\/kotlinlang.org\/docs\/install-eap-plugin.html\" target=\"_blank\" rel=\"noopener\">\u63d2\u4ef6\u7684EAP\u7248\u672c<\/a>\u3002<\/p>\n<p>\u901a\u8fc7 1.5.0-RC \u6784\u5efa\u73b0\u6709\u9879\u76ee\uff0c\u4ee5\u68c0\u67e5\u5728 1.5.0 \u4e0b\u5b83\u4eec\u5982\u4f55\u5de5\u4f5c\u3002 \u7531\u4e8e\u9884\u89c8\u7248\u672c<a href=\"https:\/\/blog.jetbrains.com\/kotlin\/2021\/03\/kotlin-1-5-0-m2-released\/\">\u66f4\u7b80\u6613\u7684\u914d\u7f6e<\/a>\uff0c\u5982\u6709\u5fc5\u8981\uff0c\u4f60\u53ea\u9700\u8981\u5c06Kotlin\u7248\u672c\u66f4\u6539\u4e3a <code>1.5.0-RC<\/code> \u5e76<a href=\"https:\/\/kotlinlang.org\/docs\/eap.html#build-details\" target=\"_blank\" rel=\"noopener\">\u8c03\u6574\u4f9d\u8d56\u7248\u672c<\/a>\u3002<\/p>\n<p align=\"center\"><a class=\"jb-download-button\" title=\"Install\" href=\"https:\/\/kotlinlang.org\/docs\/install-eap-plugin.html\" target=\"_blank\" rel=\"noopener\">\u5b89\u88c5 1.5.0-RC<\/a><\/p>\n<p>\u4e00\u5982\u5f80\u5e38\uff0c\u4f60\u53ef\u4ee5\u5728 <a href=\"https:\/\/play.kotlinlang.org\" target=\"_blank\" rel=\"noopener\">Kotlin Playground<\/a> \u5728\u7ebf\u5c1d\u8bd5\u6700\u65b0\u7684\u7248\u672c\u3002<\/p>\n<h2>Compatibility<\/h2>\n<p>\u4e0e\u6240\u6709\u4e3b\u8981\u7248\u672c\u4e00\u6837\uff0c\u67d0\u4e9b\u5148\u524d\u5ba3\u5e03\u7684\u53d8\u66f4\u7684\u5f03\u7528\u5468\u671f\u5c06\u5728 Kotlin 1.5.0 \u7248\u672c\u7ed3\u675f\u3002<br \/>\n\u6240\u6709\u8fd9\u4e9b\u60c5\u51b5\u90fd\u7ecf\u8fc7\u4e86\u8bed\u8a00\u59d4\u5458\u4f1a\u7684\u4ed4\u7ec6\u5ba1\u67e5\uff0c\u5e76\u5728 <a href=\"https:\/\/kotlinlang.org\/docs\/compatibility-guide-15.html\" target=\"_blank\" rel=\"noopener\">Kotlin 1.5 <\/a>\u517c\u5bb9\u6027\u6307\u5357\u4e2d\u5217\u51fa\u3002<br \/>\n\u60a8\u4e5f\u53ef\u4ee5\u5728 <a href=\"https:\/\/youtrack.jetbrains.com\/issues\/KT?q=Tag:%20language-committee-approved%20Target%20versions:%201.5.0-RC,%201.5.0-M2,%201.5.0-M1,%201.5.0\" target=\"_blank\" rel=\"noopener\">YouTrack<\/a> \u4e0a\u6d4f\u89c8\u8fd9\u4e9b\u53d8\u66f4\u3002<\/p>\n<h3>\u5019\u9009\u7248\u672c\u8bf4\u660e<\/h3>\n<p>Kotlin 1.5 \u6700\u7ec8\u5019\u9009\u7248\u672c\u73b0\u5df2\u63a8\u51fa\uff0c\u662f\u65f6\u5019\u5f00\u59cb\u7f16\u8bd1\u548c\u53d1\u5e03\u4e86\uff01 \u4e0e\u4ee5\u524d\u7684\u91cc\u7a0b\u7891\u7248\u672c\u4e0d\u540c\uff0c\u4f7f\u7528 Kotlin 1.5-RC \u521b\u5efa\u7684\u4e8c\u8fdb\u5236\u6587\u4ef6\u4e0e Kotlin 1.5.0 \u7684\u517c\u5bb9\u6027\u53ef\u5f97\u5230\u5145\u5206\u4fdd\u8bc1\u3002<\/p>\n<h2>\u5206\u4eab\u53cd\u9988<\/h2>\n<p>\u8fd9\u662f\u4f60\u80fd\u53c2\u4e0e\u5f71\u54cd\u4e0b\u4e00\u529f\u80fd\u7248\u672c\u7684\u6700\u540e\u673a\u4f1a\u4e86! \u4f60\u53ef\u4ee5\u5411\u6211\u4eec\u7684<a href=\"https:\/\/kotl.in\/issue\" target=\"_blank\" rel=\"noopener\">\u95ee\u9898\u8ddf\u8e2a\u5668\uff08YouTrack\uff09<\/a>\u62a5\u544a\u6240\u9047\u5230\u7684\u4efb\u4f55\u95ee\u9898\u3002 \u8ba9Kotlin 1.5.0\u4e3a\u4e86\u4f60\u548c\u793e\u533a\u53d8\u5f97\u66f4\u597d!<\/p>\n<p align=\"center\"><a class=\"jb-download-button\" title=\"Install\" href=\"https:\/\/kotlinlang.org\/docs\/install-eap-plugin.html\" target=\"_blank\" rel=\"noopener\">\u5b89\u88c5 1.5.0-RC<\/a><\/p>\n<div style=\"background-color: #f1f6fe;\">\u7279\u522b\u611f\u8c22\u7531\u6765\u81ea Kotlin \u793e\u533a\u7684 <B>Shaowei Chang<\/B>\uff0c<B>Pye52<\/B> \u4e3a\u672c\u7bc7\u535a\u6587\u63d0\u4f9b\u4e2d\u6587\u8bd1\u6587\u3002<\/div>\n","protected":false},"author":814,"featured_media":0,"comment_status":"closed","ping_status":"closed","template":"","categories":[],"tags":[21],"cross-post-tag":[],"acf":[],"_links":{"self":[{"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/kotlin\/138446"}],"collection":[{"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/kotlin"}],"about":[{"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/types\/kotlin"}],"author":[{"embeddable":true,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/users\/814"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/comments?post=138446"}],"version-history":[{"count":3,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/kotlin\/138446\/revisions"}],"predecessor-version":[{"id":138479,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/kotlin\/138446\/revisions\/138479"}],"wp:attachment":[{"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/media?parent=138446"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/categories?post=138446"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/tags?post=138446"},{"taxonomy":"cross-post-tag","embeddable":true,"href":"https:\/\/blog.jetbrains.com\/zh-hans\/wp-json\/wp\/v2\/cross-post-tag?post=138446"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}