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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 目录</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'file-paths';
}
if (e.key == "ArrowRight") {
window.location.href = 'temporary-files-and-directories';
}
}
</script>
<body>
<div class="example" id="directories">
<h2><a href="./">Go by Example 中文版</a>: 目录</h2>
<table>
<tr>
<td class="docs">
<p>对于操作文件系统中的 <em>目录</em> ，Go 提供了几个非常有用的函数。</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/zlr179K_a_a"><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">"os"</span>
<span class="s">"path/filepath"</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">check</span><span class="p">(</span><span class="nx">e</span> <span class="kt">error</span><span class="p">)</span> <span class="p">{</span>
<span class="k">if</span> <span class="nx">e</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">e</span><span class="p">)</span>
<span class="p">}</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>在当前工作目录下，创建一个子目录。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">err</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">Mkdir</span><span class="p">(</span><span class="s">"subdir"</span><span class="p">,</span> <span class="mo">0755</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>创建这个临时目录后，一个好习惯是：使用 <code>defer</code> 删除这个目录。
<code>os.RemoveAll</code> 会删除整个目录（类似于 <code>rm -rf</code>）。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="k">defer</span> <span class="nx">os</span><span class="p">.</span><span class="nf">RemoveAll</span><span class="p">(</span><span class="s">"subdir"</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>一个用于创建临时文件的帮助函数。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">createEmptyFile</span> <span class="o">:=</span> <span class="kd">func</span><span class="p">(</span><span class="nx">name</span> <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
<span class="nx">d</span> <span class="o">:=</span> <span class="p">[]</span><span class="nb">byte</span><span class="p">(</span><span class="s">""</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">os</span><span class="p">.</span><span class="nf">WriteFile</span><span class="p">(</span><span class="nx">name</span><span class="p">,</span> <span class="nx">d</span><span class="p">,</span> <span class="mo">0644</span><span class="p">))</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"> <span class="nf">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/file1"</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>我们还可以创建一个有层级的目录，使用 <code>MkdirAll</code> 函数，并包含其父目录。
这个类似于命令 <code>mkdir -p</code>。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">MkdirAll</span><span class="p">(</span><span class="s">"subdir/parent/child"</span><span class="p">,</span> <span class="mo">0755</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"> <span class="nf">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/file2"</span><span class="p">)</span>
<span class="nf">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/file3"</span><span class="p">)</span>
<span class="nf">createEmptyFile</span><span class="p">(</span><span class="s">"subdir/parent/child/file4"</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>ReadDir</code> 列出目录的内容，返回一个 <code>os.DirEntry</code> 类型的切片对象。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">c</span><span class="p">,</span> <span class="nx">err</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">ReadDir</span><span class="p">(</span><span class="s">"subdir/parent"</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</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">"Listing subdir/parent"</span><span class="p">)</span>
<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">entry</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">c</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">" "</span><span class="p">,</span> <span class="nx">entry</span><span class="p">.</span><span class="nf">Name</span><span class="p">(),</span> <span class="nx">entry</span><span class="p">.</span><span class="nf">IsDir</span><span class="p">())</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>Chdir</code> 可以修改当前工作目录，类似于 <code>cd</code>。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">Chdir</span><span class="p">(</span><span class="s">"subdir/parent/child"</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>当我们列出 <em>当前</em> 目录，就可以看到 <code>subdir/parent/child</code> 的内容了。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">c</span><span class="p">,</span> <span class="nx">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">ReadDir</span><span class="p">(</span><span class="s">"."</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</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">"Listing subdir/parent/child"</span><span class="p">)</span>
<span class="k">for</span> <span class="nx">_</span><span class="p">,</span> <span class="nx">entry</span> <span class="o">:=</span> <span class="k">range</span> <span class="nx">c</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">" "</span><span class="p">,</span> <span class="nx">entry</span><span class="p">.</span><span class="nf">Name</span><span class="p">(),</span> <span class="nx">entry</span><span class="p">.</span><span class="nf">IsDir</span><span class="p">())</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>cd</code> 回到最开始的地方。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">err</span> <span class="p">=</span> <span class="nx">os</span><span class="p">.</span><span class="nf">Chdir</span><span class="p">(</span><span class="s">"../../.."</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>当然，我们也可以遍历一个目录及其所有子目录。
<code>Walk</code> 接受一个路径和回调函数，用于处理访问到的每个目录和文件。</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">"Visiting subdir"</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">Walk</span><span class="p">(</span><span class="s">"subdir"</span><span class="p">,</span> <span class="nx">visit</span><span class="p">)</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p><code>filepath.Walk</code> 遍历访问到每一个目录和文件后，都会调用 <code>visit</code>。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="kd">func</span> <span class="nf">visit</span><span class="p">(</span><span class="nx">p</span> <span class="kt">string</span><span class="p">,</span> <span class="nx">info</span> <span class="nx">os</span><span class="p">.</span><span class="nx">FileInfo</span><span class="p">,</span> <span class="nx">err</span> <span class="kt">error</span><span class="p">)</span> <span class="kt">error</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="k">return</span> <span class="nx">err</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">" "</span><span class="p">,</span> <span class="nx">p</span><span class="p">,</span> <span class="nx">info</span><span class="p">.</span><span class="nf">IsDir</span><span class="p">())</span>
<span class="k">return</span> <span class="kc">nil</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 directories.go
<span class="go">Listing subdir/parent
</span><span class="go"> child true
</span><span class="go"> file2 false
</span><span class="go"> file3 false
</span><span class="go">Listing subdir/parent/child
</span><span class="go"> file4 false
</span><span class="go">Visiting subdir
</span><span class="go"> subdir true
</span><span class="go"> subdir/file1 false
</span><span class="go"> subdir/parent true
</span><span class="go"> subdir/parent/child true
</span><span class="go"> subdir/parent/child/file4 false
</span><span class="go"> subdir/parent/file2 false
</span><span class="go"> subdir/parent/file3 false</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="temporary-files-and-directories">临时文件和目录</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>
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