{"id":734,"date":"2021-08-01T19:43:26","date_gmt":"2021-08-01T11:43:26","guid":{"rendered":"https:\/\/fireinsect.top\/?p=734"},"modified":"2021-09-14T21:05:12","modified_gmt":"2021-09-14T13:05:12","slug":"lambda%e8%a1%a8%e8%be%be%e5%bc%8f","status":"publish","type":"post","link":"https:\/\/fireinsect.top\/index.php\/2021\/08\/01\/lambda%e8%a1%a8%e8%be%be%e5%bc%8f\/","title":{"rendered":"Lambda\u8868\u8fbe\u5f0f"},"content":{"rendered":"\n<p>Lambda\u8868\u8fbe\u5f0f\u662fJava8\u7684\u65b0\u7279\u6027\u4f7f\u5f97\u4ee3\u7801\u66f4\u4e3a\u7b80\u6d01\u6613\u61c2\u3002<\/p>\n\n\n\n<p>\u5982\u5f53\u6211\u4eec\u9700\u8981\u4f9d\u6b21\u6253\u5370\u67d0\u96c6\u5408\u7684\u5185\u5bb9\uff08\u5982\u6c34\u679c\u540d\u5b57\u96c6\u5408\uff09\uff0c\u4e4b\u524d\u6211\u4eec\u4f7f\u7528 for \u5faa\u73af\u6765\u5b8c\u6210\u6253\u5370\uff0c\u4f46\u4f7f\u7528Lambda\u8868\u8fbe\u5f0f\u5219\u53ef\u4ee5\uff1a<\/p>\n\n\n\n<!--more-->\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">fruits.forEach(f -&gt; {\n  System.out.println(f.getName());\n});\n<\/code><\/pre>\n\n\n\n<p>\u5176\u4e2d <code>f -&gt; {}<\/code>\uff0c\u5c31\u662f Lambda\u8868\u8fbe\u5f0f&nbsp;<\/p>\n\n\n\n<p>\u5176\u4e2d f \u8868\u793a\u53c2\u6570\u53d8\u91cf\uff0c\u5176\u7c7b\u578b\u53d6\u51b3\u4e8e\u4e0a\u4e0b\u6587\u7684\u9700\u6c42\uff0c\u5373Lambda\u8868\u8fbe\u5f0f\u9700\u8981\u914d\u5408\u4e0a\u4e0b\u6587\uff0c\u914d\u5408\u5176\u4ed6\u8bed\u6cd5\u4f7f\u7528\uff0c\u800c\u4e0d\u80fd\u6210\u4e3a\u5355\u72ec\u7684\u8bed\u53e5\u3002<\/p>\n\n\n\n<p>\u800c  {}  \u4e2d\u5199\u5165\u7684\u662f\u65b9\u6cd5\u7684\u4e3b\u4f53\u3002<\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-medium-font-size\"><span class=\"has-inline-color has-vivid-red-color\">\u591a\u53c2\u6570<\/span><\/p>\n\n\n\n<p>\u7bad\u5934\uff08-&gt;\uff09\u524d\u8868\u793a\u53c2\u6570\u53d8\u91cf\uff0c\u5f53\u5b58\u5728\u591a\u4e2a\u53c2\u6570\u65f6\uff0c\u9700\u8981\u7528\u5c0f\u62ec\u53f7\uff08\uff09\u5305\u88f9\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">(student1, student2) -&gt; {}<\/code><\/pre>\n\n\n\n<p class=\"has-medium-font-size\"> <span class=\"has-inline-color has-vivid-red-color\">\u65e0\u53c2\u6570<\/span> <\/p>\n\n\n\n<p>\u540c\u7406\uff0c\u5f53\u6ca1\u6709\u53c2\u6570\u53d8\u91cf\u65f6\uff0c\u4e5f\u9700\u8981\u7528\u5c0f\u62ec\u53f7\uff08\uff09\u5305\u88f9\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">() -&gt; {}<\/code><\/pre>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>\u6ce8\uff1a\u5f53\u7bad\u5934\u540e\u9762\u53ea\u6709\u4e00\u6761\u6267\u884c\u8bed\u53e5\u65f6\uff0c\u53ef\u4ee5\u4e0d\u7528\u5927\u62ec\u53f7\u5305\u88f9<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">s -&gt; System.out.println(s);<\/code><\/pre>\n\n\n\n<p>\u4f46\u5728\u5b9e\u9645\u4f7f\u7528\u4e2d\u6700\u597d\u65e0\u8bba\u591a\u5c11\u6761\u8bed\u53e5\u90fd\u52a0\u4e0a {} \u3002<\/p>\n\n\n\n<div style=\"height:31px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p>\u5f53\u7136\uff0c\u6240\u5199\u7684\u53c2\u6570\u4e5f\u53ef\u4ee5\u5e26\u7c7b\u578b\u5982\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">fruits.forEach((Fruit f) -&gt; {\n  System.out.println(f.getName());\n});<\/code><\/pre>\n\n\n\n<p>\u4f46\u6dfb\u52a0\u7c7b\u578b\u540e\u5fc5\u987b\u7528\u5c0f\u62ec\u53f7\u62ec\u4f4f\uff0c\u4e0d\u7136\u4f1a\u62a5\u9519\u3002<\/p>\n\n\n\n<div style=\"height:22px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-large-font-size\">\u5f15\u7528\u5916\u90e8\u53d8\u91cf<\/p>\n\n\n\n<p>Lambda\u8868\u8fbe\u5f0f\u7684<strong> { }<\/strong> \u5185\u6267\u884c\u7684\u8bed\u53e5\uff0c\u9664\u4e86\u80fd\u5f15\u7528\u53c2\u6570\u53d8\u91cf\uff0c\u8fd8\u53ef\u4ee5\u5f15\u7528\u5916\u90e8\u53d8\u91cf\uff0c\u4f46\u5982\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">List&lt;Fruit&gt; fruits = Arrays.asList(......);\nString message = \"\u6c34\u679c\u540d\u79f0\uff1a\";\n\nfruits.forEach(f -&gt; {\n  System.out.println(message + f.getName());\n});\n\nmessage = \"\";<\/code><\/pre>\n\n\n\n<p>\u4f1a\u62a5\u9519\u3002<\/p>\n\n\n\n<p>Lambda\u5f15\u7528\u5916\u90e8\u53d8\u91cf\u5b58\u5728\u89c4\u8303\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u89c4\u8303\u4e00\uff1a\u5f15\u7528\u7684<strong>\u5c40\u90e8\u53d8\u91cf<\/strong> \u4e0d\u5141\u8bb8\u88ab\u4fee\u6539\uff08\u5373\u4f7f\u5199\u5728\u8868\u8fbe\u5f0f\u540e\u9762\u4e5f\u4e0d\u884c\uff09<\/li><\/ul>\n\n\n\n<p>\u5f53\u7136\u5199\u5728 <strong>{ } <\/strong>\u5185\u7684\u4fee\u6539\u4e5f\u662f\u4e0d\u884c\u7684\u3002\u5373Lamdba\u8868\u8fbe\u5f0f\u5f15\u7528\u7684\u5c40\u90e8\u53d8\u91cf\u5177\u5907 <strong>final<\/strong> \u7684\u7279\u6027\u3002<\/p>\n\n\n\n<p>\u5728<strong>\u8868\u8fbe\u5f0f\u5916<\/strong>\u5b9e\u9645\u8d4b\u503c\u4e00\u6b21\u7684\u5199\u6cd5\u662f\u5141\u8bb8\u7684\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>\u89c4\u8303\u4e8c\uff1a\u53c2\u6570\u4e0d\u80fd\u4e0e\u5c40\u90e8\u53d8\u91cf\u540c\u540d\uff0c\u5982\u4e0b\u9519\u8bef<\/li><\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">String f = \"\u6c34\u679c\u540d\u79f0\uff1a\";\nfruits.forEach(f -&gt; {});<\/code><\/pre>\n\n\n\n<div style=\"height:28px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-vivid-red-color has-text-color has-large-font-size\">\u53cc\u5192\u53f7(::)\u64cd\u4f5c\u7b26<\/p>\n\n\n\n<p>\u53cc\u5192\u53f7\u53ef\u4ee5\u7b80\u5316\u64cd\u4f5c\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">List&lt;String&gt; names = Arrays.asList(\"zhangSan\", \"LiSi\", \"WangWu\");\n\nnames.forEach(n -&gt; {\n  System.out.println(n);\n});<\/code><\/pre>\n\n\n\n<p>\u7b80\u5316\u4e3a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"java\" class=\"language-java\">names.forEach(System.out::println);<\/code><\/pre>\n\n\n\n<p>\u4f7f\u7528\u53cc\u5192\u53f7\u65f6\uff0c\u7cfb\u7edf\u6bcf\u6b21\u904d\u5386\u53d6\u5f97\u7684\u5143\u7d20(n)\uff0c\u90fd\u548c\u81ea\u52a8\u4f20\u9012\u7ed9\u9700\u8981\u53c2\u6570\u7684\u8bed\u53e5\uff08\u5982System.out.println()\uff09<\/p>\n\n\n\n<p><code>System.out::println<\/code>\u00a0\u7b49\u540c\u4e8e\u00a0<code>n -> {System.out.println(n);}<\/code><\/p>\n\n\n\n<p style=\"font-size:25px\">\u8bed\u6cd5\u542b\u4e49<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" src=\"https:\/\/style.youkeda.com\/img\/ham\/course\/j5\/j5-1-5-1.svg\" alt=\"\"\/><\/figure>\n\n\n\n<div style=\"height:8px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-vivid-red-color has-text-color\" style=\"font-size:25px\">\u7528\u6cd5:<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li><strong>\u7528\u6cd5\u4e00\uff1a\u9759\u6001\u65b9\u6cd5\u8c03\u7528<\/strong><\/li><\/ul>\n\n\n\n<p>\u5982\u4f7f\u7528<code> LambdaTest::print<\/code>\u00a0\u4ee3\u66ff\u00a0<code>f -> LambdaTest.print(f)<\/code>\uff0c\u7b80\u5316\u4e86\u4ee3\u7801<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li><strong>\u7528\u6cd5\u4e8c\uff1a\u8c03\u7528\u975e\u9759\u6001\u65b9\u6cd5<\/strong><\/li><\/ul>\n\n\n\n<p><code>print()<\/code>&nbsp;\u65b9\u6cd5\u4e0d\u518d\u6807\u8bc6\u4e3a&nbsp;<code>static<\/code>\uff0c\u4e8e\u662f\u9700\u8981\u5b9e\u4f8b\u5bf9\u8c61\u6765\u8c03\u7528\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">fruits.forEach(<strong>new<\/strong> LambdaTest()::print);\n<\/code><\/pre>\n\n\n\n<p>\u53ea\u662f\u7b80\u5199\u4e86\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">LambdaTest lt = <strong>new<\/strong> LambdaTest();\nfruits.forEach(lt::print);\n<\/code><\/pre>\n\n\n\n<p>\u6548\u679c\u662f\u4e00\u6837\u7684\u3002<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li><strong>\u7528\u6cd5\u4e09\uff1a\u591a\u53c2\u6570<\/strong><\/li><\/ul>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">Collections.sort(students, (student1, student2) -&gt; {\n  <em>\/\/ \u7b2c\u4e00\u4e2a\u53c2\u6570\u7684\u5b66\u53f7 vs \u7b2c\u4e8c\u4e2a\u53c2\u6570\u7684\u5b66\u53f7<\/em>\n  <strong>return<\/strong> student1.getRollNo() - student2.getRollNo();\n});\n<\/code><\/pre>\n\n\n\n<p>\u78b0\u5230\u4e86\u591a\u53c2\u6570\u7684\u60c5\u51b5\u3002\u5982\u679c\u628a\u6bd4\u8f83\u7684\u8fc7\u7a0b\u5b9a\u4e49\u6210\u4e00\u4e2a\u65b9\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\"><strong>private<\/strong> <strong>static<\/strong> <strong>int<\/strong> <strong>compute<\/strong>(Student s1, Student s2) {\n  ... ...\n  ... ...\n}\n<\/code><\/pre>\n\n\n\n<p>\u90a3\u4e48\uff0c\u6392\u5e8f\u8fc7\u7a0b\u5c31\u53ef\u4ee5\u7b80\u5199\u4e3a\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code class=\"\">Collections.sort(students, SortTest::compute);\n<\/code><\/pre>\n\n\n\n<p>\u6ce8\u610f\uff0c\u7cfb\u7edf\u4f1a\u00a0<em><strong>\u81ea\u52a8<\/strong><\/em>\u00a0\u83b7\u53d6\u4e0a\u4e0b\u6587\u7684\u53c2\u6570\uff0c\u5e76\u6309\u4e0a\u4e0b\u6587\u5b9a\u4e49\u7684\u00a0<strong>\u987a\u5e8f<\/strong>\u00a0\u4f20\u9012\u7ed9\u6307\u5b9a\u7684\u65b9\u6cd5\u3002\u6240\u8c13\u00a0<em>\u987a\u5e8f<\/em>\u00a0\u5c31\u662f\u00a0<em>Lambda<\/em>\u00a0\u8868\u8fbe\u5f0f\u00a0<code>()<\/code>\u00a0\u4e2d\u7684\u987a\u5e8f\u3002<\/p>\n\n\n\n<ul class=\"has-medium-font-size wp-block-list\"><li><strong>\u7528\u6cd5\u56db\uff1a\u7236\u7c7b\u65b9\u6cd5<\/strong><\/li><\/ul>\n\n\n\n<p><code>super<\/code>\u00a0\u5173\u952e\u5b57\u7684\u4f5c\u7528\u662f\u5728\u5b50\u7c7b\u4e2d\u5f15\u7528\u7236\u7c7b\u7684\u5c5e\u6027\u6216\u8005\u65b9\u6cd5\u3002\u90a3\u4e48\u540c\u6837\uff0c<code>::<\/code>\u00a0\u8bed\u6cd5\u4e5f\u53ef\u4ee5\u7528\u00a0<code>super<\/code>\u5173\u952e\u8bcd\u8c03\u7528\u7236\u7c7b\u7684\u975e\u9759\u6001\u65b9\u6cd5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Lambda\u8868\u8fbe\u5f0f\u662fJava8\u7684\u65b0\u7279\u6027\u4f7f\u5f97\u4ee3\u7801\u66f4\u4e3a\u7b80\u6d01\u6613\u61c2\u3002 \u5982\u5f53\u6211\u4eec\u9700\u8981\u4f9d\u6b21\u6253\u5370\u67d0\u96c6\u5408\u7684\u5185\u5bb9\uff08\u5982\u6c34\u679c\u540d\u5b57\u96c6\u5408 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":""},"categories":[6,1],"tags":[],"class_list":["post-734","post","type-post","status-publish","format-standard","hentry","category-6","category-wcd"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/posts\/734"}],"collection":[{"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/comments?post=734"}],"version-history":[{"count":5,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/posts\/734\/revisions"}],"predecessor-version":[{"id":967,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/posts\/734\/revisions\/967"}],"wp:attachment":[{"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/media?parent=734"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/categories?post=734"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fireinsect.top\/index.php\/wp-json\/wp\/v2\/tags?post=734"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}