{"id":681,"date":"2023-11-29T09:01:01","date_gmt":"2023-11-29T01:01:01","guid":{"rendered":""},"modified":"2023-11-29T09:01:01","modified_gmt":"2023-11-29T01:01:01","slug":"\u62fc\u63a5\u5b57\u7b26\u4e32\u65b0\u59ff\u52bf\u2014StringJoiner","status":"publish","type":"post","link":"https:\/\/mushiming.com\/681.html","title":{"rendered":"\u62fc\u63a5\u5b57\u7b26\u4e32\u65b0\u59ff\u52bf\u2014StringJoiner"},"content":{"rendered":"<p>\u8fd9\u662f\u6211\u53c2\u4e0e\u66f4\u6587\u6311\u6218\u7684\u7b2c4\u5929\uff0c\u6d3b\u52a8\u8be6\u60c5\u67e5\u770b\uff1a \u66f4\u6587\u6311\u6218<\/p>\n<h2 data-id=\"heading-0\">\u524d\u8a00<\/h2>\n<p>\u4f60\u77e5\u9053\u4f7f\u7528\u539f\u751f JDK \u62fc\u63a5\u5b57\u7b26\u4e32\u6709\u591a\u5c11\u79cd\u73a9\u6cd5\u5417\uff1f\u6211\u4eec\u80fd\u60f3\u5230\u7684\u5927\u6982\u5c31\u662fStringBuilder\u3001StringBuffer\u3001 String.concat\u3001\u8fd8\u6709\u7528 + \u62fc\u63a5\u3002\u8fd8\u6709\u5176\u4ed6\u7684\u5417\uff1f\u63a5\u4e0b\u6765\u5c31\u6765\u8bb2\u8bb2 Java 8 \u91cc\u9762\u65b0\u589e\u4e86\u4e00\u4e2a\u62fc\u63a5\u5b57\u7b26\u4e32\u7684\u7c7b \uff0c\u53eb StringJoiner \u7684\u7528\u6cd5\u3002<\/p>\n<h2 data-id=\"heading-1\">\u6982\u8ff0<\/h2>\n<p>StringJoiner \u662f java.util \u5305\u4e2d\u7684\u4e00\u4e2a\u7c7b\uff0c\u7528\u4e8e\u6784\u9020\u4e00\u4e2a\u7531\u5206\u9694\u7b26\u5206\u9694\u7684\u5b57\u7b26\u4e32\uff0c\u5e76\u4e14\u53ef\u4ee5\u4ece\u63d0\u4f9b\u7684\u524d\u7f00\u5b57\u7b26\u4e32\u5f00\u5934\uff0c\u4ee5\u63d0\u4f9b\u7684\u540e\u7f00\u5b57\u7b26\u4e32\u7ed3\u5c3e\u3002\u867d\u7136\u8fd9\u4e9b\u529f\u80fd\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528 StringBuilder \u6216\u8005 StringBuffer \u6765\u5b9e\u73b0\u7684\uff0c \u4f46\u662f StringJoiner \u63d0\u4f9b\u7684\u65b9\u6cd5\u66f4\u7b80\u5355\uff0c\u800c\u4e14\u4e5f\u4e0d\u9700\u8981\u5199\u5927\u91cf\u7684\u4ee3\u7801\u5c31\u80fd\u6210\u3002<\/p>\n<h2 data-id=\"heading-2\">\u6784\u9020\u51fd\u6570<\/h2>\n<p>StringJoiner \u4e00\u5171\u6709 2 \u4e2a\u6784\u9020\u51fd\u6570\u3002 \u6784\u9020\u51fd\u6570\u5f88\u7b80\u5355\uff0c\u5c31\u662f\u5bf9 \u5206\u9694\u7b26\uff0c\u524d\u7f00\u548c\u540e\u7f00\u5b57\u7b26\u4e32\u7684\u521d\u59cb\u5316\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\">    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-title function_\">StringJoiner<\/span><span class=\"hljs-params\">(CharSequence delimiter)<\/span> {\n        <span class=\"hljs-built_in\">this<\/span>(delimiter, <span class=\"hljs-string\">\"\"<\/span>, <span class=\"hljs-string\">\"\"<\/span>);<span class=\"hljs-comment\">\/\/\u9ed8\u8ba4\u524d\u7f00\u548c\u540e\u7f00\u4e3a\"\",\u91cd\u8f7d\u8c03\u7528<\/span>\n    }\n\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-title function_\">StringJoiner<\/span><span class=\"hljs-params\">(CharSequence delimiter, CharSequence prefix, CharSequence suffix)<\/span> {\n        <span class=\"hljs-comment\">\/\/\u95f4\u9694\u7b26\uff0c\u524d\u7f00\u548c\u540e\u7f00\u5224\u65ad\u662f\u5426\u4e3anull\uff0cnull\u5c06\u629b\u51fa\u5f02\u5e38<\/span>\n        Objects.requireNonNull(prefix, <span class=\"hljs-string\">\"The prefix must not be null\"<\/span>);\n        Objects.requireNonNull(delimiter, <span class=\"hljs-string\">\"The delimiter must not be null\"<\/span>);\n        Objects.requireNonNull(suffix, <span class=\"hljs-string\">\"The suffix must not be null\"<\/span>);\n        <span class=\"hljs-comment\">\/\/\u6210\u5458\u53d8\u91cf\u8d4b\u503c<\/span>\n        <span class=\"hljs-built_in\">this<\/span>.prefix = prefix.toString();\n        <span class=\"hljs-built_in\">this<\/span>.delimiter = delimiter.toString();\n        <span class=\"hljs-built_in\">this<\/span>.suffix = suffix.toString();\n        <span class=\"hljs-comment\">\/\/\u7a7a\u503c\u88ab\u8bbe\u7f6e\u4e3a\u53ea\u6709\u524d\u540e\u7f00<\/span>\n        <span class=\"hljs-built_in\">this<\/span>.emptyValue = <span class=\"hljs-built_in\">this<\/span>.prefix + <span class=\"hljs-built_in\">this<\/span>.suffix;\n    }\n<\/code><\/pre>\n<h2 data-id=\"heading-3\">\u7528\u6cd5<\/h2>\n<p>StringJoiner \u7684\u7528\u6cd5\u5176\u5b9e\u5f88\u7b80\u5355\uff0c\u6765\uff0c\u6211\u4eec\u770b\u4e00\u4e0b StringJoiner \u5b57\u7b26\u4e32\u62fc\u63a5\u7684\u7528\u6cd5\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">StringJoinerTest<\/span> {\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> <span class=\"hljs-keyword\">void<\/span> <span class=\"hljs-title function_\">main<\/span><span class=\"hljs-params\">(String[] args)<\/span> {\n        <span class=\"hljs-type\">StringJoiner<\/span> <span class=\"hljs-variable\">sj<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">StringJoiner<\/span>(<span class=\"hljs-string\">\"hello\"<\/span>);\n        sj.add(<span class=\"hljs-string\">\"Java 8 \"<\/span>);\n        sj.add(<span class=\"hljs-string\">\"Java 11\"<\/span>);\n        System.out.println(sj.toString());\n        <span class=\"hljs-type\">StringJoiner<\/span> <span class=\"hljs-variable\">sj1<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">StringJoiner<\/span>(<span class=\"hljs-string\">\":\"<\/span>,<span class=\"hljs-string\">\"[\"<\/span>,<span class=\"hljs-string\">\"]\"<\/span>);\n        sj1.add(<span class=\"hljs-string\">\"Java8\"<\/span>).add(<span class=\"hljs-string\">\"Java11\"<\/span>).add(<span class=\"hljs-string\">\"Java15\"<\/span>);\n        System.out.println(sj1.toString());\n    }\n}\n<\/code><\/pre>\n<p>\u8f93\u51fa\u7ed3\u679c\uff1a<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\">Java <span class=\"hljs-number\">8<\/span> helloJava <span class=\"hljs-number\">11<\/span>\n[Java8:Java11:Java15]\n<\/code><\/pre>\n<p><code>\u6ce8\u610f\uff1a<\/code><\/p>\n<ol>\n<li>\u5f53\u6211\u4eec\u4f7f\u7528StringJoiner(CharSequence delimiter)\u521d\u59cb\u5316\u4e00\u4e2aStringJoiner\u7684\u65f6\u5019\uff0c\u8fd9\u4e2adelimiter\u5176\u5b9e\u662f\u5206\u9694\u7b26\uff0c\u5e76\u4e0d\u662f\u5b57\u7b26\u4e32\u7684\u521d\u59cb\u503c\u3002<\/li>\n<li>StringJoiner(CharSequence delimiter,CharSequence prefix,CharSequence suffix)\u7684\u7b2c\u4e8c\u4e2a\u548c\u7b2c\u4e09\u4e2a\u53c2\u6570\u5206\u522b\u662f\u62fc\u63a5\u540e\u7684\u5b57\u7b26\u4e32\u7684\u524d\u7f00\u548c\u540e\u7f00\u3002<\/li>\n<\/ol>\n<h2 data-id=\"heading-4\">\u6e90\u7801\u5206\u6790<\/h2>\n<blockquote>\n<p>JDK8\u4e2d\u6e90\u7801<\/p>\n<\/blockquote>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\">  <span class=\"hljs-keyword\">public<\/span> StringJoiner <span class=\"hljs-title function_\">setEmptyValue<\/span><span class=\"hljs-params\">(CharSequence emptyValue)<\/span> {\n        <span class=\"hljs-built_in\">this<\/span>.emptyValue = Objects.requireNonNull(emptyValue,\n            <span class=\"hljs-string\">\"The empty value must not be null\"<\/span>).toString();\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-built_in\">this<\/span>;\n    }\n\n    <span class=\"hljs-meta\">@Override<\/span>\n    <span class=\"hljs-keyword\">public<\/span> String <span class=\"hljs-title function_\">toString<\/span><span class=\"hljs-params\">()<\/span> {\n        <span class=\"hljs-keyword\">if<\/span> (value == <span class=\"hljs-literal\">null<\/span>) {\n            <span class=\"hljs-keyword\">return<\/span> emptyValue;\n        } <span class=\"hljs-keyword\">else<\/span> {\n            <span class=\"hljs-keyword\">if<\/span> (suffix.equals(<span class=\"hljs-string\">\"\"<\/span>)) {\n                <span class=\"hljs-keyword\">return<\/span> value.toString();\n            } <span class=\"hljs-keyword\">else<\/span> {\n                <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">initialLength<\/span> <span class=\"hljs-operator\">=<\/span> value.length();\n                <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">result<\/span> <span class=\"hljs-operator\">=<\/span> value.append(suffix).toString();\n                value.setLength(initialLength);\n                <span class=\"hljs-keyword\">return<\/span> result;\n            }\n        }\n    }\n\n    <span class=\"hljs-keyword\">public<\/span> StringJoiner <span class=\"hljs-title function_\">add<\/span><span class=\"hljs-params\">(CharSequence newElement)<\/span> {\n        prepareBuilder().append(newElement);\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-built_in\">this<\/span>;\n    }\n\n    <span class=\"hljs-keyword\">public<\/span> StringJoiner <span class=\"hljs-title function_\">merge<\/span><span class=\"hljs-params\">(StringJoiner other)<\/span> {\n        Objects.requireNonNull(other);\n        <span class=\"hljs-keyword\">if<\/span> (other.value != <span class=\"hljs-literal\">null<\/span>) {\n            <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">length<\/span> <span class=\"hljs-operator\">=<\/span> other.value.length();\n            <span class=\"hljs-type\">StringBuilder<\/span> <span class=\"hljs-variable\">builder<\/span> <span class=\"hljs-operator\">=<\/span> prepareBuilder();\n            builder.append(other.value, other.prefix.length(), length);\n        }\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-built_in\">this<\/span>;\n    }\n\n    <span class=\"hljs-keyword\">private<\/span> StringBuilder <span class=\"hljs-title function_\">prepareBuilder<\/span><span class=\"hljs-params\">()<\/span> {\n        <span class=\"hljs-keyword\">if<\/span> (value != <span class=\"hljs-literal\">null<\/span>) {\n            value.append(delimiter);\n        } <span class=\"hljs-keyword\">else<\/span> {\n            value = <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">StringBuilder<\/span>().append(prefix);\n        }\n        <span class=\"hljs-keyword\">return<\/span> value;\n    }\n\n\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-type\">int<\/span> <span class=\"hljs-title function_\">length<\/span><span class=\"hljs-params\">()<\/span> {\n        <span class=\"hljs-keyword\">return<\/span> (value != <span class=\"hljs-literal\">null<\/span> ? value.length() + suffix.length() :\n                emptyValue.length());\n    }\n<\/code><\/pre>\n<blockquote>\n<p>JDK11\u4e2d\u6e90\u7801<\/p>\n<\/blockquote>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\"><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">StringJoiner<\/span> {\n    <span class=\"hljs-keyword\">private<\/span> String[] elts;\n    \n    <span class=\"hljs-meta\">@Override<\/span>\n    <span class=\"hljs-keyword\">public<\/span> String <span class=\"hljs-title function_\">toString<\/span><span class=\"hljs-params\">()<\/span> {\n        <span class=\"hljs-keyword\">final<\/span> String[] elts = <span class=\"hljs-built_in\">this<\/span>.elts;\n        <span class=\"hljs-keyword\">if<\/span> (elts == <span class=\"hljs-literal\">null<\/span> &amp;&amp; emptyValue != <span class=\"hljs-literal\">null<\/span>) {\n            <span class=\"hljs-keyword\">return<\/span> emptyValue;\n        }\n        <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">size<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-built_in\">this<\/span>.size;\n        <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">addLen<\/span> <span class=\"hljs-operator\">=<\/span> prefix.length() + suffix.length();\n        <span class=\"hljs-keyword\">if<\/span> (addLen == <span class=\"hljs-number\">0<\/span>) {\n            compactElts();\n            <span class=\"hljs-keyword\">return<\/span> size == <span class=\"hljs-number\">0<\/span> ? <span class=\"hljs-string\">\"\"<\/span> : elts[<span class=\"hljs-number\">0<\/span>];\n        }\n        <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">delimiter<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-built_in\">this<\/span>.delimiter;\n        <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">char<\/span>[] chars = <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">char<\/span>[len + addLen];\n        <span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">k<\/span> <span class=\"hljs-operator\">=<\/span> getChars(prefix, chars, <span class=\"hljs-number\">0<\/span>);\n        <span class=\"hljs-keyword\">if<\/span> (size &gt; <span class=\"hljs-number\">0<\/span>) {\n            k += getChars(elts[<span class=\"hljs-number\">0<\/span>], chars, k);\n            <span class=\"hljs-keyword\">for<\/span> (<span class=\"hljs-type\">int<\/span> <span class=\"hljs-variable\">i<\/span> <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-number\">1<\/span>; i &lt; size; i++) {\n                k += getChars(delimiter, chars, k);\n                k += getChars(elts[i], chars, k);\n            }\n        }\n        k += getChars(suffix, chars, k);\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">String<\/span>(chars);\n    }\n    <span class=\"hljs-keyword\">public<\/span> StringJoiner <span class=\"hljs-title function_\">add<\/span><span class=\"hljs-params\">(CharSequence newElement)<\/span> {\n        <span class=\"hljs-keyword\">final<\/span> <span class=\"hljs-type\">String<\/span> <span class=\"hljs-variable\">elt<\/span> <span class=\"hljs-operator\">=<\/span> String.valueOf(newElement);\n        <span class=\"hljs-keyword\">if<\/span> (elts == <span class=\"hljs-literal\">null<\/span>) {\n            elts = <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">String<\/span>[<span class=\"hljs-number\">8<\/span>];\n        } <span class=\"hljs-keyword\">else<\/span> {\n            <span class=\"hljs-keyword\">if<\/span> (size == elts.length)\n                elts = Arrays.copyOf(elts, <span class=\"hljs-number\">2<\/span> * size);\n            len += delimiter.length();\n        }\n        len += elt.length();\n        elts[size++] = elt;\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-built_in\">this<\/span>;\n    }\n}\n<\/code><\/pre>\n<p>\u6bd4\u8f83\u4e00\u4e0bJDK8\u548cJDK11\u4e2dStringJoiner\u7684\u6e90\u7801add \u65b9\u6cd5\u7684\u5b9e\u73b0\uff1a<\/p>\n<ol>\n<li>\n<p>JDK8\u4e2dStringJoiner \u662f\u901a\u8fc7 StringBuilder \u6765\u5b9e\u73b0\u7684\uff1b<\/p>\n<\/li>\n<li>\n<p>JDK11\u4e2dStringJoiner \u5c31\u662f\u628a\u5f85\u62fc\u63a5\u7684\u5b57\u7b26\u4e32\uff0c\u653e\u5230\u4e00\u4e2a\u5b57\u7b26\u4e32\u6570\u7ec4\u91cc\u9762\uff0ctoString() \u65b9\u6cd5\u7684\u65f6\u5019\uff0c\u624d\u662f\u771f\u6b63\u505a\u5b57\u7b26\u4e32\u62fc\u63a5\u7684\u8fc7\u7a0b\u3002<\/p>\n<\/li>\n<\/ol>\n<p>\u90a3\u4e48\u95ee\u9898\u6765\u4e86\uff0c\u65e2\u7136 JDK 8 \u7684\u65f6\u5019\uff0c\u5df2\u7ecf\u4f7f\u7528\u4e86StringBuilder \u6765\u5b9e\u73b0\uff0cJDK11\u4e3a\u4ec0\u4e48\u8fd8\u8981\u6539\u6210 String[] \u6765\u7f13\u5b58\u6240\u6709\u7684\u5f85\u62fc\u63a5\u7684\u5b57\u7b26\u4e32\u3002\u8fd9\u4e2a\u5c31\u8981\u6d89\u53ca\u5230JVM\u5e95\u5c42\u7684\u4f18\u5316\u4e86\u3002<\/p>\n<p>\u65e2\u7136\u5df2\u7ecf\u6709\u4e86StringBuilder\uff0c\u4e3a\u4ec0\u4e48\u8fd8\u8981\u9020\u4e00\u4e2aStringJoiner\uff0c\u5b83\u7684\u4f18\u52bf\u5230\u5e95\u5728\u54ea\u91cc\uff0c\u90a3\u6211\u4eec\u518d\u6765\u627e\u627e\u539f\u56e0\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230\u4ee3\u7801\u7684\u6ce8\u91ca\u5757\u4e2d\uff0c\u6807\u8bb0\u4e86 Collectors#joining \u3002<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/p9-juejin.byteimg.com\/tos-cn-i-k3u1fbpfcp\/ce26f08903704d389ebb671ff66c6b42~tplv-k3u1fbpfcp-zoom-in-crop-mark:1512:0:0:0.awebp\" =\"image-20210620082312132.png\" loading=\"lazy\" alt=\"\u62fc\u63a5\u5b57\u7b26\u4e32\u65b0\u59ff\u52bf\u2014StringJoiner (https:\/\/mushiming.com\/) \u6280\u672f\u535a\u5ba2 \u7b2c1\u5f20\" title=\"\u62fc\u63a5\u5b57\u7b26\u4e32\u65b0\u59ff\u52bf\u2014StringJoiner \u6280\u672f\u535a\u5ba2 \u7b2c1\u5f20-\u7a46\u4e16\u660e\u535a\u5ba2\" ><\/p>\n<p>\u6211\u4eec\u770b\u770b Collectors#joining \u7a76\u7adf\u505a\u4e86\u4ec0\u4e48\u5462\uff1f<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"hljs language-java\" lang=\"java\">    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> Collector&lt;CharSequence, ?, String&gt; joining() {\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">CollectorImpl<\/span>&lt;CharSequence, StringBuilder, String&gt;(\n                StringBuilder::<span class=\"hljs-keyword\">new<\/span>, StringBuilder::append,\n                (r1, r2) -&gt; { r1.append(r2); <span class=\"hljs-keyword\">return<\/span> r1; },\n                StringBuilder::toString, CH_NOID);\n    }\n\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> Collector&lt;CharSequence, ?, String&gt; joining(CharSequence delimiter) {\n        <span class=\"hljs-keyword\">return<\/span> joining(delimiter, <span class=\"hljs-string\">\"\"<\/span>, <span class=\"hljs-string\">\"\"<\/span>);\n    }\n\n\n    <span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">static<\/span> Collector&lt;CharSequence, ?, String&gt; joining(CharSequence delimiter,\n                                                             CharSequence prefix,\n                                                             CharSequence suffix) {\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">CollectorImpl<\/span>&lt;&gt;(\n                () -&gt; <span class=\"hljs-keyword\">new<\/span> <span class=\"hljs-title class_\">StringJoiner<\/span>(delimiter, prefix, suffix),\n                StringJoiner::add, StringJoiner::merge,\n                StringJoiner::toString, CH_NOID);\n    }\n<\/code><\/pre>\n<p>\u539f\u6765 Java 8 \u4e2dStream \u662f\u501f\u52a9\u4e86 StringJoiner \u6765\u5b9e\u73b0\u7684\u3002 \u8fd9\u4e2a\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u80fd\u4f1a\u60f3\uff0c\u4e3a\u4ec0\u4e48\u4e0d\u4f7f\u7528 StringBuilder \u6765\u5b9e\u73b0\u5462\uff1f \u6211\u4eec\u53ef\u4ee5\u4ece\u793a\u4f8b\u91cc\u770b\u51fa\uff0c\u5982\u679c StringBuilder \u6765\u6784\u9020\u62fc\u63a5\u7684\u8bdd\uff0c\u5728\u6ca1\u6709\u524d\u540e\u7f00\u7684\u60c5\u51b5\u4e0b\uff0c\u5e94\u8be5\u8fd8\u662f\u7b80\u5355\u7684\uff0c\u4f46\u662f\u4e00\u65e6\u5230\u9700\u8981\u5176\u4ed6\u524d\u540e\u7f00\u7684\u62fc\u63a5\uff0c\u90a3\u8fd9\u4e2a\u5c31\u53d8\u5f97\u5f88\u590d\u6742\u5566\u3002<\/p>\n<p>\u6240\u4ee5 StringJoiner \u5728 Java 8 \u7684\u5730\u4f4d\u662f StringBuilder \u6240\u4e0d\u80fd\u4ee3\u66ff\u7684\u3002<\/p>\n<h2 data-id=\"heading-5\">\u603b\u7ed3<\/h2>\n<p>\u672c\u6587\u4ecb\u7ecd\u4e86 Java 8 \u5f00\u59cb\u63d0\u4f9b\u7684\u5b57\u7b26\u4e32\u62fc\u63a5\u7c7b StringJoiner\u3002 JDK 8 \u4e2d StringJoiner \u662f\u901a\u8fc7 StringBuilder \u5b9e\u73b0\u7684\uff0c \u6240\u4ee5\u5b83\u7684\u6027\u80fd\u548cStringBuilder \u5dee\u4e0d\u591a\uff0c\u5b83\u4e5f\u662f\u975e\u7ebf\u7a0b\u5b89\u5168\u7684\u3002JDK 11 \u4e2d\u5df2\u7ecf\u5bf9\u5176\u8fdb\u884c\u4e86\u4f18\u5316\uff0c\u901a\u8fc7 String[] \u6765\u4ee3\u7406 StringBuilder \u3002<\/p>\n<p>\u5728\u65e5\u5e38\u7684\u5f00\u53d1\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u600e\u4e48\u9009\u62e9\u5b57\u7b26\u4e32\u62fc\u63a5\u7c7b\u5462\uff1f<\/p>\n<ol>\n<li>\u7b80\u5355\u7684\u5b57\u7b26\u4e32\u62fc\u63a5\uff0c\u76f4\u63a5\u4f7f\u7528 + \u5373\u53ef\u3002<\/li>\n<li>\u5728 for \u5faa\u73af\u4e4b\u7c7b\u7684\u573a\u666f\u4e0b\u9700\u8981\u5b57\u7b26\u4e32\u62fc\u63a5\uff0c\u53ef\u4ee5\u4f18\u5148\u8003\u8651\u4f7f\u7528 StringBuilder \u3002<\/li>\n<li>\u5728\u4f7f\u7528 Java Stream \u548c lambda \u7684\u573a\u666f\u4e0b\u9700\u8981\u5b57\u7b26\u4e32\u62fc\u63a5\uff0c\u53ef\u4ee5\u4f18\u5148\u8003\u8651\u4f7f\u7528 StringJoiner\u3002<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"\u62fc\u63a5\u5b57\u7b26\u4e32\u65b0\u59ff\u52bf\u2014StringJoiner\u4f60\u77e5\u9053\u4f7f\u7528\u539f\u751f JDK \u62fc\u63a5\u5b57\u7b26\u4e32\u6709\u591a\u5c11\u79cd\u73a9\u6cd5\u5417\uff1f\u6211\u4eec\u80fd\u60f3\u5230\u7684\u5927\u6982\u5c31\u662fStringBuilder\u3001StringBu...","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/681"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=681"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/681\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=681"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=681"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=681"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}