{"id":1262,"date":"2015-07-11T08:14:38","date_gmt":"2015-07-11T00:14:38","guid":{"rendered":"http:\/\/coderbee.net\/?p=1262"},"modified":"2015-07-11T08:16:17","modified_gmt":"2015-07-11T00:16:17","slug":"%e3%80%8a%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3-scala%e3%80%8b%e7%ac%ac%e4%b8%80%e7%ab%a0-scala-%e4%b8%80%e7%a7%8d%e6%b7%b7%e5%90%88%e5%bc%8f%e7%bc%96%e7%a8%8b%e8%af%ad%e8%a8%80","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/scala\/20150711\/1262","title":{"rendered":"\u300a\u6df1\u5165\u7406\u89e3 Scala\u300b\u7b2c\u4e00\u7ae0 &#8212; Scala \u4e00\u79cd\u6df7\u5408\u5f0f\u7f16\u7a0b\u8bed\u8a00"},"content":{"rendered":"<p>Scala \u7684\u9884\u671f\u76ee\u6807\u662f\u5c06\u9762\u5411\u5bf9\u8c61\u3001\u51fd\u6570\u5f0f\u7f16\u7a0b\u548c\u5f3a\u5927\u7684\u7c7b\u578b\u7cfb\u7edf\u7ed3\u5408\u8d77\u6765\uff0c\u540c\u65f6\u4ecd\u7136\u8981\u80fd\u5199\u51fa\u4f18\u96c5\u3001\u7b80\u6d01\u7684\u4ee3\u7801\u3002<\/p>\n<p>Scala \u89c6\u56fe\u5c06\u4ee5\u4e0b\u4e09\u7ec4\u5bf9\u7acb\u7684\u601d\u60f3\u878d\u5408\u5230\u4e00\u79cd\u8bed\u8a00\u4e2d\uff1a<\/p>\n<ul>\n<li>\u51fd\u6570\u5f0f\u7f16\u7a0b\u548c\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b<\/li>\n<li>\u5bcc\u6709\u8868\u8fbe\u529b\u7684\u8bed\u6cd5\u548c\u9759\u6001\u7c7b\u578b<\/li>\n<li>\u9ad8\u7ea7\u7684\u8bed\u8a00\u7279\u6027\u540c\u4e8b\u4fdd\u6301\u4e0e Java \u7684\u9ad8\u5ea6\u96c6\u6210<\/li>\n<\/ul>\n<h3>\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b<\/h3>\n<p>\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b\u662f\u4e00\u79cd\u81ea\u9876\u5411\u4e0b\u7684\u7a0b\u5e8f\u8bbe\u8ba1\u65b9\u6cd5\uff0c\u5c06\u4ee3\u7801\u4ee5\u540d\u8bcd\uff08\u5bf9\u8c61\uff09\u505a\u5207\u5272\uff0c\u6bcf\u4e2a\u5bf9\u8c61\u6709\u67d0\u79cd\u5f62\u5f0f\u7684\u6807\u8bc6\u7b26\uff08self\/this\uff09\u3001\u884c\u4e3a\uff08\u65b9\u6cd5\uff09\u548c\u72b6\u6001\uff08\u6210\u5458\u53d8\u91cf\uff09\u3002\u8bc6\u522b\u51fa\u540d\u8bcd\u5e76\u4e14\u5b9a\u4e49\u51fa\u5b83\u4eec\u7684\u884c\u4e3a\u540e\uff0c\u518d\u5b9a\u4e49\u51fa\u540d\u8bcd\u4e4b\u95f4\u7684\u4ea4\u4e92\u3002\u5b9e\u73b0\u4ea4\u4e92\u65f6\uff0c\u5fc5\u987b\u5c06\u8fd9\u4e9b\u4ea4\u4e92\u653e\u5728\u5176\u4e2d\u4e00\u4e2a\u5bf9\u8c61\u4e2d\uff08\u800c\u4e0d\u80fd\u72ec\u7acb\u5b58\u5728\uff09\u3002\u73b0\u4ee3\u9762\u5411\u5bf9\u8c61\u8bbe\u8ba1\u503e\u5411\u4e8e\u5b9a\u4e49\u51fa\u201d\u670d\u52a1\u7c7b\u201c\uff0c\u5c06\u64cd\u4f5c\u591a\u4e2a\u9886\u57df\u5bf9\u8c61\u7684\u65b9\u6cd5\u96c6\u5408\u653e\u5728\u91cc\u9762\u3002\u8fd9\u4e9b\u670d\u52a1\u7c7b\u867d\u7136\u4e5f\u662f\u5bf9\u8c61\uff0c\u4f46\u901a\u5e38\u4e0d\u5177\u6709\u72ec\u7acb\u72b6\u6001\uff0c\u4e5f\u6ca1\u6709\u4e0e\u5b83\u4eec\u6240\u64cd\u4f5c\u7684\u5bf9\u8c61\u65e0\u5173\u7684\u72ec\u7acb\u884c\u4e3a\u3002<\/p>\n<h3>\u51fd\u6570\u5f0f\u7f16\u7a0b<\/h3>\n<p>\u51fd\u6570\u5f0f\u7f16\u7a0b\u65b9\u6cd5\u901a\u8fc7\u7ec4\u5408\u548c\u5e94\u7528\u51fd\u6570\u6765\u6784\u9020\u8f6f\u4ef6\u3002\u51fd\u6570\u5f0f\u7f16\u7a0b\u901a\u5e38\u503e\u5411\u4e8e\u5c06\u8f6f\u4ef6\u5206\u89e3\u4e3a\u5176\u9700\u8981\u6267\u884c\u7684\u884c\u4e3a\u6216\u64cd\u4f5c\uff0c\u800c\u4e14\u901a\u5e38\u91c7\u7528\u81ea\u5e95\u5411\u4e0a\u7684\u65b9\u6cd5\u3002\u51fd\u6570\u5f0f\u7f16\u7a0b\uff1a\u5bf9\u4e0d\u53ef\u53d8\u6027\u7684\u5f3a\u8c03\u6709\u52a9\u4e8e\u7f16\u5199\u5e76\u53d1\u7a0b\u5e8f\uff0c\u89c6\u56fe\u5c06\u526f\u4f5c\u7528\u63a8\u8fdf\u5230\u5c3d\u53ef\u80fd\u665a\uff0c\u63d0\u4f9b\u4e86\u975e\u5e38\u5f3a\u5927\u7684\u5bf9\u4e8b\u7269\u8fdb\u884c\u62bd\u8c61\u548c\u7ec4\u5408\u7684\u80fd\u529b\u3002\u6d88\u9664\u526f\u4f5c\u7528\u4f7f\u5f97\u5bf9\u7a0b\u5e8f\u8fdb\u884c\u63a8\u7406\uff08reasoning\uff09\u53d8\u5f97\u5bb9\u6613\u3002<\/p>\n<p><!--more--><\/p>\n<p>\u5bf9\u6bd4\uff1a<\/p>\n<table>\n<tr>\n<td>\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b<\/td>\n<td>\u51fd\u6570\u5f0f\u7f16\u7a0b<\/td>\n<\/tr>\n<tr>\n<td>\u5bf9\u8c61\u7684\u7ec4\u5408\uff08\u540d\u8bcd\uff09<\/td>\n<td>\u51fd\u6570\u7684\u7ec4\u5408\uff08\u52a8\u8bcd\uff09<\/td>\n<\/tr>\n<tr>\n<td>\u5c01\u88c5\u6709\u72b6\u6001\u7684\u4ea4\u4e92<\/td>\n<td>\u63a8\u8fdf\u526f\u4f5c\u7528<\/td>\n<\/tr>\n<tr>\n<td>\u8fed\u4ee3\u7b97\u6cd5<\/td>\n<td>\u9012\u5f52\u7b97\u6cd5<\/td>\n<\/tr>\n<tr>\n<td>\u547d\u4ee4\u6d41<\/td>\n<td>\u5ef6\u8fdf\u8ba1\u7b97<\/td>\n<\/tr>\n<tr>\n<td>&#8230;<\/td>\n<td>\u6a21\u5f0f\u5339\u914d<\/td>\n<\/tr>\n<tr>\n<td>&#8230;<\/td>\n<td><\/td>\n<\/tr>\n<\/table>\n<p>\u534f\u53d8\uff0cConvariance\uff0c<code>+T  or  ? extends T<\/code> \uff1a\u7c7b\u578b\u53ef\u4ee5\u5f3a\u5236\u8f6c\u6362\u4e3a\u5b50\u5b59\u7c7b\uff1b<br \/>\n\u9006\u53d8\uff0cContravariance, <code>-T  or ? super T<\/code> \uff1a\u7c7b\u578b\u53ef\u4ee5\u5f3a\u5236\u8f6c\u6362\u4e3a\u7956\u5148\u7c7b\uff1b<br \/>\n\u4e0d\u53d8\uff0cInvariance \uff1a\u7c7b\u578b\u5b8c\u5168\u4e0d\u80fd\u88ab\u5f3a\u5236\u8f6c\u6362\u3002<\/p>\n<p>\u51fd\u6570\u5f0f\u7f16\u7a0b\u7684\u7cbe\u9ad3\u5728\u4e8e\u5c3d\u53ef\u80fd\u5730\u63a8\u8fdf\u526f\u4f5c\u7528\u3002<\/p>\n<p>Scala \u505a\u4e86\u4ee5\u4e0b\u51e0\u4e2a\u8bbe\u8ba1\u51b3\u7b56\u6765\u63d0\u9ad8\u4ee3\u7801\u8868\u8fbe\u529b\uff1a<\/p>\n<ul>\n<li>\u628a\u7c7b\u578b\u6807\u6ce8\uff08type annotation\uff09\u6362\u5230\u53d8\u91cf\u53f3\u8fb9\uff1b<\/li>\n<li>\u7c7b\u578b\u63a8\u65ad\uff1b<\/li>\n<li>\u53ef\u6269\u5c55\u7684\u8bed\u6cd5\uff1b<\/li>\n<li>\u7528\u6237\u81ea\u5b9a\u4e49\u7684\u9690\u5f0f\u8f6c\u6362\u3002<\/li>\n<\/ul>\n<p>\u64cd\u4f5c\u7b26\uff08operation notation\uff09\u662f Scala \u7684\u4e00\u4e2a\u80fd\u529b\uff0c\u53ef\u4ee5\u628a\u65b9\u6cd5\u5f53\u4f5c\u64cd\u4f5c\u7b26\u3002\u65e0\u53c2\u6570\u7684\u65b9\u6cd5\u53ef\u4ee5\u7528\u4f5c\u540e\u7f00\u64cd\u4f5c\u7b26\uff0c\u53ea\u6709\u4e00\u4e2a\u53c2\u6570\u7684\u65b9\u6cd5\u53ef\u4ee5\u5f53\u4f5c\u4e2d\u7f00\u64cd\u4f5c\u7b26\uff1b\u65b9\u6cd5\u540d\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u5982\u679c\u662f\u5192\u53f7 \u201d:\u201c\uff0c\u5219\u65b9\u6cd5\u7684\u8c03\u7528\u65b9\u5411\u53cd\u8f6c\u3002<\/p>\n<p>\u5728\u5b9a\u4e49\u533f\u540d\u51fd\u6570\u65f6\uff08\u53c8\u79f0 lambda\uff09\uff0cScala \u63d0\u4f9b\u4e86\u5360\u4f4d\u7b26\u8bed\u6cd5\u3002\u53ef\u4ee5\u7528 &#8220;_&#8221; \u5173\u952e\u5b57\u4f5c\u4e3a\u51fd\u6570\u53c2\u6570\u7684\u5360\u4f4d\u7b26\u3002\u5982\u679c\u4f7f\u7528\u591a\u4e2a\u5360\u4f4d\u7b26\uff0c\u6bcf\u4e2a\u76f8\u5e94\u4f4d\u7f6e\u7684\u5360\u4f4d\u7b26\u5bf9\u5e94\u4e8e\u76f8\u5e94\u4f4d\u7f6e\u7684\u53c2\u6570\u3002<\/p>\n<p>\u7528\u597d\u9690\u5f0f\u8f6c\u6362\u662f\u64cd\u7eb5 Scala \u7c7b\u578b\u7cfb\u7edf\u7684\u5173\u952e\u3002\u9690\u5f0f\u8f6c\u6362\u7684\u57fa\u7840\u5e94\u7528\u573a\u666f\u662f\u6309\u9700\u81ea\u52a8\u5730\u628a\u4e00\u79cd\u7c7b\u578b\u8f6c\u6362\u4e3a\u53e6\u4e00\u79cd\uff0c\u4f46\u5b83\u4e5f\u53ef\u4ee5\u7528\u4e8e\u6709\u9650\u5f62\u5f0f\u7684\u7f16\u8bd1\u65f6\u5143\u7f16\u7a0b\u3002\u8981\u4f7f\u7528\u9690\u5f0f\u8f6c\u6362\u5fc5\u987b\u628a\u5b83\u5173\u8054\u5230\u67d0\u4e2a\u4f5c\u7528\u57df\uff0c\u53ef\u4ee5\u901a\u8fc7\u4f34\u751f\u5bf9\u8c61\u6216\u660e\u786e\u5bfc\u5165\u6765\u505a\u5173\u8054\u3002<\/p>\n<h3>HotSpot<\/h3>\n<p>HotSpot \u7f16\u8bd1\u5668\u7684\u4f18\u5316\u6280\u672f\uff1a<\/p>\n<ul>\n<li>\u65b9\u6cd5\u5185\u8054\uff08method inlining\uff09\uff1aHotSpot \u80fd\u591f\u5224\u65ad\u662f\u5426\u80fd\u5728\u8c03\u7528\u70b9\u76f4\u63a5\u628a\u88ab\u8c03\u7528\u7684\u5c0f\u65b9\u6cd5\u7684\u5185\u5bb9\u5d4c\u5165\u8fdb\u53bb\u3002<\/li>\n<li>\u6808\u66ff\u6362\uff08On Stack Replacement\uff09\uff1a\u6307 HotSpot \u80fd\u591f\u5224\u65ad\u4e00\u4e2a\u53d8\u91cf\u5e94\u8be5\u653e\u5728\u6808\u91cc\u8fd8\u662f\u5806\u91cc\u3002<\/li>\n<li>\u9003\u9038\u5206\u6790\uff08Escape Analysis\uff09\uff1aHotSpot \u5206\u6790\u5404\u79cd\u4e1c\u897f\u662f\u5426\u9038\u51fa\u4e86\u7279\u5b9a\u4f5c\u7528\u4e8e\uff0c\u8fd9\u9879\u6280\u672f\u4e3b\u8981\u7528\u6765\u5728\u540c\u6b65\u65b9\u6cd5\u8c03\u7528\u9650\u5b9a\u4e8e\u67d0\u4e2a\u4f5c\u7528\u57df\u65f6\u51cf\u5c11\u9501\u5f00\u9500\u3002<\/li>\n<li>\u52a8\u6001\u53bb\u4f18\u5316\uff08Dynamic De-optimization\uff09\uff1a\u662f HotSpot \u7684\u4e00\u4e2a\u5173\u952e\u7279\u6027\uff0c\u5b83\u6709\u80fd\u529b\u5224\u65ad\u4e00\u4e2a\u4f18\u5316\u662f\u5426\u4e8b\u5b9e\u4e0a\u6ca1\u6709\u63d0\u5347\u6027\u80fd\uff0c\u7136\u540e\u53d6\u6d88\u8be5\u4f18\u5316\uff0c\u6539\u7528\u5176\u4ed6\u4f18\u5316\u3002<\/li>\n<\/ul>\n<hr\/>\n<p>\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: <strong>coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"258\" height=\"258\" src=\"https:\/\/coderbee.net\/wp-content\/uploads\/2019\/01\/coderbee-note.jpg\" class=\"alignnone size-full wp-image-1707\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Scala \u7684\u9884\u671f\u76ee\u6807\u662f\u5c06\u9762\u5411\u5bf9\u8c61\u3001\u51fd\u6570\u5f0f\u7f16\u7a0b\u548c\u5f3a\u5927\u7684\u7c7b\u578b\u7cfb\u7edf\u7ed3\u5408\u8d77\u6765\uff0c\u540c\u65f6\u4ecd\u7136 &hellip; <a href=\"https:\/\/coderbee.net\/index.php\/scala\/20150711\/1262\">\u7ee7\u7eed\u9605\u8bfb <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[181],"tags":[234,227],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1262"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=1262"}],"version-history":[{"count":1,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1262\/revisions"}],"predecessor-version":[{"id":1263,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/1262\/revisions\/1263"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=1262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=1262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=1262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}