{"id":2022,"date":"2018-05-01T23:18:57","date_gmt":"2018-05-01T14:18:57","guid":{"rendered":"http:\/\/www.code-magagine.com\/?p=2022"},"modified":"2023-05-27T20:40:27","modified_gmt":"2023-05-27T11:40:27","slug":"%e3%80%90java%e3%80%91%e6%96%87%e5%ad%97%e5%88%97%e9%80%a3%e7%b5%90%e3%81%ae%e5%ae%9f%e8%a1%8c%e9%80%9f%e5%ba%a6%e3%81%ae%e6%af%94%e8%bc%83","status":"publish","type":"post","link":"http:\/\/www.code-magagine.com\/?p=2022","title":{"rendered":"\u3010Java\u3011+\u6f14\u7b97\u5b50\u3001StringBuilder\u3001StringBuffer\u306e\u9055\u3044\uff08\u5b9f\u969b\u306b\u6e2c\u3063\u3066\u307f\u305f\u3002\uff09\u3001\u6587\u5b57\u5217\u7cfb\u306e\u578b"},"content":{"rendered":"<p>Java\u306e\u6587\u5b57\u5217\u9023\u7d50\u306b\u306f\u3001\u4e0b\u8a18\u306e\u3088\u3046\u306b\u8272\u3005\u306a\u65b9\u6cd5\u304c\u3042\u308a\u307e\u3059\u3088\u306d\u3002<\/p>\n<ul>\n<li>String\u30af\u30e9\u30b9\u306e+\u6f14\u7b97\u5b50\u3092\u4f7f\u3063\u305f\u65b9\u6cd5<\/li>\n<li>StringBuffer\u3092\u4f7f\u3063\u305f\u65b9\u6cd5<\/li>\n<li>StringBuilder\u3092\u4f7f\u3063\u305f\u65b9\u6cd5<\/li>\n<\/ul>\n<h2>\u5b9f\u884c\u901f\u5ea6\u306b\u3064\u3044\u3066<\/h2>\n<p>\u4e00\u822c\u7684\u306b\u306f\u3001\u5b9f\u884c\u901f\u5ea6\u306f\u4e0b\u8a18\u3068\u8a00\u308f\u308c\u3066\u3044\u307e\u3059\u3002<\/p>\n<div class=\"graybox\">StringBuilder &gt; StringBuffer &gt;&gt;&gt;&gt;&gt; +\u6f14\u7b97\u5b50<\/div>\n<h3>\u5b9f\u969b\u3069\u3046\u306a\u306e\u304b\uff1f<\/h3>\n<p>\u305d\u308c\u305e\u308c\u3001<span style=\"color: #ff0000;\"><strong>10\u4e07\u56de\u30eb\u30fc\u30d7\u3055\u305b\u3066\u3001\u304b\u304b\u308b\u6642\u9593\u3092\u8a08\u6e2c\u3057\u3066\u307f\u307e\u3059\u3002<\/strong><\/span><\/p>\n<h4>+\u6f14\u7b97\u5b50<\/h4>\n<pre class=\"lang:default decode:true\">String plus = \"\";\r\n\r\nlong start = System.currentTimeMillis();\r\n\r\nfor(int i = 0 ;i &lt; 100000;i++) {\r\n\tplus = plus + \"\u3042\";\r\n}\r\n\r\nlong end = System.currentTimeMillis();\r\n\r\nSystem.out.println((end - start)  + \"ms\");<\/pre>\n<p><strong>\u5b9f\u884c\u7d50\u679c<\/strong><\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2044\" src=\"http:\/\/www.code-magagine.com\/wp-content\/uploads\/2018\/05\/\u30d7\u30e9\u30b9\u6f14\u7b97\u5b50.png\" alt=\"\" width=\"269\" height=\"104\" \/><\/p>\n<h3>StringBuilder<\/h3>\n<pre class=\"lang:default decode:true\">StringBuilder sb = new StringBuilder();\r\n\r\nlong start = System.currentTimeMillis();\r\n\r\nfor(int i = 0 ;i &lt; 100000;i++) {\r\n\tsb = sb.append(\"\u3042\");\r\n}\r\n\r\nlong end = System.currentTimeMillis();\r\n\r\nSystem.out.println((end - start)  + \"ms\");<\/pre>\n<p><strong>\u5b9f\u884c\u7d50\u679c<\/strong><\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2043\" src=\"http:\/\/www.code-magagine.com\/wp-content\/uploads\/2018\/05\/StringBuilder.png\" alt=\"\" width=\"271\" height=\"87\" \/><\/p>\n<h3>StringBuffer<\/h3>\n<pre class=\"lang:default decode:true\">StringBuffer sb = new StringBuffer();\r\n\r\nlong start = System.currentTimeMillis();\r\n\r\nfor(int i = 0 ;i &lt; 100000;i++) {\r\n\tsb = sb.append(\"\u3042\");\r\n}\r\n\r\nlong end = System.currentTimeMillis();\r\n\r\nSystem.out.println((end - start)  + \"ms\");<\/pre>\n<p><strong>\u5b9f\u884c\u7d50\u679c<\/strong><\/p>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2042\" src=\"http:\/\/www.code-magagine.com\/wp-content\/uploads\/2018\/05\/StringBuffer.png\" alt=\"\" width=\"279\" height=\"106\" \/><\/p>\n<p>\u4e00\u822c\u7684\u306b\u306f\u3001<strong>\u300c<span style=\"color: #ff0000;\">StringBuilder &gt; StringBuffer &gt;&gt;&gt;&gt;&gt; \u30d7\u30e9\u30b9\u6f14\u7b97\u5b50<\/span>\u300d<\/strong>\u3068\u8a00\u308f\u308c\u3066\u3044\u307e\u3059\u304c\u3001\u300c<span style=\"color: #ff0000;\"><strong>StringBuffer &gt;\u00a0StringBuilder &gt;&gt;&gt;&gt;&gt; \u30d7\u30e9\u30b9\u6f14\u7b97\u5b50<\/strong><\/span>\u300d\u306b\u306a\u308a\u307e\u3057\u305f\u306d\u3002<\/p>\n<p>\u8a66\u3057\u305f\u9806\u756a\u306b\u3082\u3088\u308b\u306e\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u306d\u3002<\/p>\n<h2>StringBuilder<\/h2>\n<pre class=\"lang:default decode:true\">StringBuilder sb = new StringBuilder();\r\nsb.append(\"\u3042\");\r\nsb.append(\"\u3044\");\r\nsb.append(\"\u3046\");\r\nSystem.out.println(sb.toString());<\/pre>\n<p>\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u306e\u5185\u90e8\u306b\u9023\u7d50\u3057\u305f<span style=\"color: #ff0000;\"><strong>\u6587\u5b57\u5217\u3092\u84c4\u3048\u308b\u30e1\u30e2\u30ea\u9818\u57df<\/strong><\/span>\u3092\u4fdd\u6301\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n<p>\u4e00\u756a\u901f\u5ea6\u304c\u901f\u3044\u306e\u3067\u3001<span style=\"color: #ff0000;\"><strong>\u305f\u3044\u3066\u3044\u306e\u5834\u5408\u306f\u3053\u308c\u3092\u4f7f\u3044\u307e\u3057\u3087\u3046\uff01<\/strong><\/span><\/p>\n<h3>\u30e1\u30ea\u30c3\u30c8<\/h3>\n<p>\u53ef\u5909\u306a\u8a2d\u8a08\u306a\u306e\u3067\u3001\u6587\u5b57\u5217\u3092append\u30e1\u30bd\u30c3\u30c9\u3067\u8ffd\u52a0\u3059\u308b\u5ea6\u306b\u3001<span style=\"color: #ff0000;\"><strong>new\u3059\u308b\u3053\u3068\u306a\u304f\u3001\u30e1\u30e2\u30ea\u306b\u65b0\u305f\u306b\u8ffd\u52a0\u3057\u3066\u3044\u304f\u306e\u3067\u975e\u5e38\u306b\u9ad8\u901f<\/strong><\/span>\u3002<\/p>\n<h3>\u30c7\u30e1\u30ea\u30c3\u30c8<\/h3>\n<p>\u57fa\u672c\u7684\u306b\u306f\u3001\u901f\u5ea6\u306e\u65e9\u3044\u300c<span style=\"color: #ff0000;\"><strong>StringBuilder\u30af\u30e9\u30b9<\/strong><\/span>\u300d\u3092\u4f7f\u3048\u3070\u3044\u3044\u306e\u3067\u3059\u304c<span style=\"color: #ff0000;\"><strong>\u6b20\u70b9\u3082\u3042\u308a\u307e\u3059\u3002<\/strong><\/span><\/p>\n<p>\u30b9\u30ec\u30c3\u30c9\u51e6\u7406\uff08\u8907\u6570\u306e\u51e6\u7406\u3092\u540c\u6642\u306b\u884c\u3046\u305f\u3081\u306eJava\u306e\u4ed5\u7d44\u307f\uff09\u306e\u5834\u5408\u306b\u3001\u4e0d\u5177\u5408\u304c\u767a\u751f\u3059\u308b\u5834\u5408\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<p>\u305d\u306e\u5834\u5408\u306f\u3001\u4ee3\u308f\u308a\u306b<span style=\"color: #ff0000;\"><strong>\u300cStringBuffer\u30af\u30e9\u30b9\u300d<\/strong><\/span>\u3092\u4f7f\u7528\u3057\u307e\u3057\u3087\u3046\u3002<\/p>\n<h2>Stringbuffer<\/h2>\n<pre class=\"lang:default decode:true \">StringBuffer sb = new StringBuffer();\r\nsb.append(\"\u3042\");\r\nsb.append(\"\u3044\");\r\nsb.append(\"\u3046\");\r\nSystem.out.println(sb.toString());<\/pre>\n<p>StringBuilder\u30af\u30e9\u30b9\u306b\u6bd4\u3079\u308b\u3068\u82e5\u5e72\u9045\u3044\u3067\u3059\u304c\u3001\u305d\u308c\u3067\u3082\u300c+\u6f14\u7b97\u5b50\u300d\u306b\u6bd4\u3079\u308b\u3068\u975e\u5e38\u306b\u65e9\u3044\u3067\u3059\u3002<\/p>\n<h2>+\u6f14\u7b97\u5b50<\/h2>\n<pre class=\"lang:default decode:true \">String plus = \"\u3042\" + \"\u3044\" + \"\u3046\";\r\nSystem.out.println(plus);\r\n<\/pre>\n<p><span style=\"color: #ff0000;\"><strong>+\u3067String\u3092\u9023\u7d50\u3059\u308b\u305f\u3073\u306b\u3001\u53e4\u3044\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u306f\u6368\u3066\u3089\u308c\u3066\u3001\u65b0\u3057\u3044\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u304cnew\u306b\u3088\u308a\u751f\u6210\u3055\u308c\u3066\u3044\u307e\u3059\u3002<\/strong><\/span><\/p>\n<p><span style=\"color: #ff0000;\"><strong>new\u306b\u3088\u308b\u30a4\u30f3\u30b9\u30bf\u30f3\u30b9\u306e\u751f\u6210\u306f\u3001JVM\u306b\u975e\u5e38\u306b\u8ca0\u8377\u3092\u304b\u3051\u308b<\/strong><\/span>\u306e\u3067\u3001StringBuilder\u3084\u3001StringBuffer\u306b\u6bd4\u3079\u308b\u3068\u9045\u304f\u306a\u308a\u307e\u3059\u3002<\/p>\n<h3>\u30e1\u30ea\u30c3\u30c8<\/h3>\n<ul>\n<li>String\u30af\u30e9\u30b9\u306a\u306e\u3067\u3001\u3044\u3061\u3044\u3061\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u306e\u4e2d\u306bnew\u3092\u66f8\u304f\u5fc5\u8981\u304c\u306a\u304f\u30b9\u30c3\u30ad\u30ea\u3059\u308b\u3002<\/li>\n<li>\u30e1\u30bd\u30c3\u30c9\u3092\u4f7f\u308f\u305a\u3001\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u304c\u76f4\u611f\u7684\u306b\u7406\u89e3\u3067\u304d\u308b\u3002<\/li>\n<\/ul>\n<h2>\u307e\u3068\u3081<\/h2>\n<p>\u6570\u500b\u7a0b\u5ea6\u306e\u6587\u5b57\u5217\u9023\u7d50\u3067\u3042\u308c\u3070\u3001\u30bd\u30fc\u30b9\u30b3\u30fc\u30c9\u306e\u8a18\u8ff0\u91cf\u304c\u5c11\u306a\u3044<span style=\"color: #ff0000;\"><strong>\u300c+\u6f14\u7b97\u5b50\u300d<\/strong><\/span>\u3092\u4f7f\u3044\u307e\u3057\u3087\u3046\u3002<\/p>\n<p>\u305f\u3060\u3001\u4f8b\u3048\u3070\u3001CSV\u30d5\u30a1\u30a4\u30eb\u3092\u4f5c\u308b\u7b49\u306e\u5927\u91cf\u306e\u6587\u5b57\u5217\u9023\u7d50\u51e6\u7406\u304c\u767a\u751f\u3059\u308b\u51e6\u7406\u7b49\u306f\u3001<span style=\"color: #ff0000;\"><strong>\u300cStringBuilder\u300d<\/strong><\/span>\u3082\u3057\u304f\u306f\u3001<span style=\"color: #ff0000;\"><strong>\u300cStringBuffer\u300d<\/strong><\/span>\u3092\u4f7f\u3046\u3088\u3046\u306b\u3057\u307e\u3057\u3087\u3046\uff01<\/p>\n<h2>\u6587\u5b57\u5217\u306e\u578b<\/h2>\n<p>Java\u3067\u3001\u6587\u5b57\u5217\u3092\u6271\u3046\u5834\u5408\u306f\u3001String\u30af\u30e9\u30b9\u3092\u4f7f\u7528\u3059\u308b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n<p>\u305f\u3060\u3001\u4ed6\u306b\u3082\u4e0b\u8a18\u306e\u3088\u3046\u306a\u6271\u3044\u65b9\u3092\u3057\u307e\u3059\u3002<\/p>\n<h3>char\u914d\u5217<\/h3>\n<p>String\u306b\u542b\u307e\u308c\u308b\u6587\u5b57\u3092char\u914d\u5217\u306b\u683c\u7d0d\u3057\u307e\u3059\u3002<\/p>\n<h4>\u69cb\u6587<\/h4>\n<p>String\u3092\u3001char\u914d\u5217\u306b\u5909\u63db\u3059\u308b\u5834\u5408\u306f\u3001String\u30af\u30e9\u30b9\u306e\u300c<span style=\"color: #ff0000;\"><strong>toCharArray\u30e1\u30bd\u30c3\u30c9<\/strong><\/span>\u300d\u3092\u4f7f\u3044\u307e\u3059\u3002<\/p>\n<h4>\u7528\u9014<\/h4>\n<p>1\u6587\u5b57\u305a\u3064\u3001\u30eb\u30fc\u30d7\u3092\u56de\u3057\u3066\u3001\u51e6\u7406\u3092\u3057\u305f\u3044\u5834\u5408\u306b\u4f7f\u3046\u3002<\/p>\n<h4>\u30b5\u30f3\u30d7\u30eb<\/h4>\n<pre class=\"lang:default decode:true\">String str = \"\u3042\u3044\u3046\u3048\u304a\";\r\nchar[] chrData = str.toCharArray();\r\n\r\nfor(int i=0;i&lt;chrData.length;i++) {\r\n\tSystem.out.println(chrData[i]);\r\n}<\/pre>\n<p>\u6a19\u6e96\u51fa\u529b\u306b\u3001\u4e00\u6587\u5b57\u305a\u3064\u6587\u5b57\u3092\u51fa\u529b\u3059\u308b\u30b5\u30f3\u30d7\u30eb\u3067\u3059\u3002<\/p>\n<h4>\u5b9f\u884c\u7d50\u679c<\/h4>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2058\" src=\"http:\/\/www.code-magagine.com\/wp-content\/uploads\/2018\/05\/char\u914d\u5217.png\" alt=\"\" width=\"280\" height=\"144\" \/><\/p>\n<h3>byte\u914d\u5217<\/h3>\n<p>\u6587\u5b57\u5217\u306e\u60c5\u5831\u3092\u30d0\u30a4\u30c8\u5217\u306b\u5909\u63db\u3057\u3066\u30011\u30d0\u30a4\u30c8\u3054\u3068\u306b\u914d\u5217\u306b\u683c\u7d0d\u3057\u305f\u72b6\u614b\u306b\u3057\u307e\u3059\u3002<\/p>\n<h4>\u69cb\u6587<\/h4>\n<p>String\u3092\u3001byte\u914d\u5217\u306b\u5909\u63db\u3059\u308b\u5834\u5408\u306f\u3001String\u30af\u30e9\u30b9\u306e\u300c<span style=\"color: #ff0000;\"><strong>getBytes<\/strong><strong>\u30e1\u30bd\u30c3\u30c9<\/strong><\/span>\u300d\u3092\u4f7f\u3044\u307e\u3059\u3002<\/p>\n<h4>\u7528\u9014<\/h4>\n<p>\u6307\u5b9a\u3057\u305f\u6587\u5b57\u30b3\u30fc\u30c9\u3067\u30d5\u30a1\u30a4\u30eb\u306b\u4fdd\u5b58\u3057\u305f\u308a\u3059\u308b\u5834\u5408\u306b\u4f7f\u7528\u3057\u305f\u308a\u3057\u307e\u3059\u3002<\/p>\n<h4>\u30b5\u30f3\u30d7\u30eb<\/h4>\n<pre class=\"lang:default decode:true\">String str = \"\u3042\u3044\u3046\u3048\u304a\";\r\ntry {\r\n\tbyte[] byteData = str.getBytes(\"UTF-8\");\r\n\r\n\tfor(int i=0;i&lt;byteData.length;i++) {\r\n\t\tSystem.out.println(byteData[i]);\r\n\t}\r\n\r\n} catch (UnsupportedEncodingException e) {\r\n\te.printStackTrace();\r\n}<\/pre>\n<h4>\u5b9f\u884c\u7d50\u679c<\/h4>\n<p><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2059\" src=\"http:\/\/www.code-magagine.com\/wp-content\/uploads\/2018\/05\/byte\u914d\u5217.png\" alt=\"\" width=\"290\" height=\"256\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"Java\u306e\u6587\u5b57\u5217\u9023\u7d50\u306b\u306f\u3001\u4e0b\u8a18\u306e\u3088\u3046\u306b\u8272\u3005\u306a\u65b9\u6cd5\u304c\u3042\u308a\u307e\u3059\u3088\u306d\u3002 String\u30af\u30e9\u30b9\u306e+\u6f14\u7b97\u5b50\u3092\u4f7f\u3063\u305f\u65b9\u6cd5 StringBuffer\u3092\u4f7f\u3063\u305f\u65b9\u6cd5 StringBuilder\u3092\u4f7f\u3063\u305f\u65b9\u6cd5 \u5b9f\u884c\u901f\u5ea6\u306b\u3064\u3044\u3066 \u4e00\u822c\u7684\u306b\u306f\u3001\u5b9f\u884c [&hellip;]","protected":false},"author":1,"featured_media":1095,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5],"tags":[],"_links":{"self":[{"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/posts\/2022"}],"collection":[{"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2022"}],"version-history":[{"count":22,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/posts\/2022\/revisions"}],"predecessor-version":[{"id":20245,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/posts\/2022\/revisions\/20245"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=\/wp\/v2\/media\/1095"}],"wp:attachment":[{"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2022"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2022"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.code-magagine.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2022"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}