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file-paths.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 文件路径</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
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}
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<body>
<div class="example" id="file-paths">
<h2><a href="./">Go by Example 中文版</a>: 文件路径</h2>
<table>
<tr>
<td class="docs">
<p><code>filepath</code> 包为 <em>文件路径</em> ，提供了方便的跨操作系统的解析和构建函数；
比如：Linux 下的 <code>dir/file</code> 和 Windows 下的 <code>dir\file</code> 。</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="https://play.studygolang.com/p/9Spis9glc46"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kn">import</span> <span class="p">(</span>
<span class="s">"fmt"</span>
<span class="s">"path/filepath"</span>
<span class="s">"strings"</span>
<span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>应使用 <code>Join</code> 来构建可移植(跨操作系统)的路径。
它接收任意数量的参数，并参照传入顺序构造一个对应层次结构的路径。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">p</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Join</span><span class="p">(</span><span class="s">"dir1"</span><span class="p">,</span> <span class="s">"dir2"</span><span class="p">,</span> <span class="s">"filename"</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"p:"</span><span class="p">,</span> <span class="nx">p</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>您应该总是使用 <code>Join</code> 代替手动拼接 <code>/</code> 和 <code>\</code>。
除了可移植性，<code>Join</code> 还会删除多余的分隔符和目录，使得路径更加规范。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nf">Join</span><span class="p">(</span><span class="s">"dir1//"</span><span class="p">,</span> <span class="s">"filename"</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nf">Join</span><span class="p">(</span><span class="s">"dir1/../dir1"</span><span class="p">,</span> <span class="s">"filename"</span><span class="p">))</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>Dir</code> 和 <code>Base</code> 可以被用于分割路径中的目录和文件。
此外，<code>Split</code> 可以一次调用返回上面两个函数的结果。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"Dir(p):"</span><span class="p">,</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Dir</span><span class="p">(</span><span class="nx">p</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"Base(p):"</span><span class="p">,</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Base</span><span class="p">(</span><span class="nx">p</span><span class="p">))</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>判断路径是否为绝对路径。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nf">IsAbs</span><span class="p">(</span><span class="s">"dir/file"</span><span class="p">))</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">filepath</span><span class="p">.</span><span class="nf">IsAbs</span><span class="p">(</span><span class="s">"/dir/file"</span><span class="p">))</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"> <span class="nx">filename</span> <span class="o">:=</span> <span class="s">"config.json"</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>某些文件名包含了扩展名（文件类型）。
我们可以用 <code>Ext</code> 将扩展名分割出来。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">ext</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Ext</span><span class="p">(</span><span class="nx">filename</span><span class="p">)</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">ext</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>想获取文件名清除扩展名后的值，请使用 <code>strings.TrmSuffix</code>。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">strings</span><span class="p">.</span><span class="nf">TrimSuffix</span><span class="p">(</span><span class="nx">filename</span><span class="p">,</span> <span class="nx">ext</span><span class="p">))</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>Rel</code> 寻找 <code>basepath</code> 与 <code>targpath</code> 之间的相对路径。
如果相对路径不存在，则返回错误。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">rel</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Rel</span><span class="p">(</span><span class="s">"a/b"</span><span class="p">,</span> <span class="s">"a/b/t/file"</span><span class="p">)</span>
<span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
<span class="nb">panic</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
<span class="p">}</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">rel</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code">
<pre class="chroma"> <span class="nx">rel</span><span class="p">,</span> <span class="nx">err</span> <span class="p">=</span> <span class="nx">filepath</span><span class="p">.</span><span class="nf">Rel</span><span class="p">(</span><span class="s">"a/b"</span><span class="p">,</span> <span class="s">"a/c/t/file"</span><span class="p">)</span>
<span class="k">if</span> <span class="nx">err</span> <span class="o">!=</span> <span class="kc">nil</span> <span class="p">{</span>
<span class="nb">panic</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
<span class="p">}</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">rel</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
</td>
<td class="code">
<pre class="chroma"><span class="gp">$</span> go run file-paths.go
<span class="go">p: dir1/dir2/filename
</span><span class="go">dir1/filename
</span><span class="go">dir1/filename
</span><span class="go">Dir(p): dir1/dir2
</span><span class="go">Base(p): filename
</span><span class="go">false
</span><span class="go">true
</span><span class="go">.json
</span><span class="go">config
</span><span class="go">t/file
</span><span class="go">../c/t/file</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="directories">目录</a>
</p>
<p class="footer">
<a href="https://twitter.com/mmcgrana">@mmcgrana</a> 和<a href="https://eli.thegreenplace.net">Eli Bendersky</a>编写 | <a href="https://github.com/gobyexample-cn">gobyexample-cn</a> 翻译 | <a href="https://github.com/gobyexample-cn/gobyexample/issues">反馈</a> | <a href="https://github.com/gobyexample-cn/gobyexample">源码</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> </p>
</p>
</div>
<script>
var codeLines = [];
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"path/filepath\"\u000A \"strings\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' p :\u003D filepath.Join(\"dir1\", \"dir2\", \"filename\")\u000A fmt.Println(\"p:\", p)\u000A');codeLines.push(' fmt.Println(filepath.Join(\"dir1//\", \"filename\"))\u000A fmt.Println(filepath.Join(\"dir1/../dir1\", \"filename\"))\u000A');codeLines.push(' fmt.Println(\"Dir(p):\", filepath.Dir(p))\u000A fmt.Println(\"Base(p):\", filepath.Base(p))\u000A');codeLines.push(' fmt.Println(filepath.IsAbs(\"dir/file\"))\u000A fmt.Println(filepath.IsAbs(\"/dir/file\"))\u000A');codeLines.push(' filename :\u003D \"config.json\"\u000A');codeLines.push(' ext :\u003D filepath.Ext(filename)\u000A fmt.Println(ext)\u000A');codeLines.push(' fmt.Println(strings.TrimSuffix(filename, ext))\u000A');codeLines.push(' rel, err :\u003D filepath.Rel(\"a/b\", \"a/b/t/file\")\u000A if err !\u003D nil {\u000A panic(err)\u000A }\u000A fmt.Println(rel)\u000A');codeLines.push(' rel, err \u003D filepath.Rel(\"a/b\", \"a/c/t/file\")\u000A if err !\u003D nil {\u000A panic(err)\u000A }\u000A fmt.Println(rel)\u000A}\u000A');codeLines.push('');
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