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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 临时文件和目录</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'directories';
}
if (e.key == "ArrowRight") {
window.location.href = 'testing-and-benchmarking';
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<body>
<div class="example" id="temporary-files-and-directories">
<h2><a href="./">Go by Example 中文版</a>: 临时文件和目录</h2>
<table>
<tr>
<td class="docs">
<p>在程序运行时，我们经常创建一些运行时用到，程序结束后就不再使用的数据。
<em>临时目录和文件</em> 对于上面的情况很有用，因为它不会随着时间的推移而污染文件系统。</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/3xju207mqQ3"><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>创建临时文件最简单的方法是调用 <code>os.CreateTemp</code> 函数。
它会创建并打开文件，我们可以对文件进行读写。
函数的第一个参数传 <code>""</code>，<code>os.CreateTemp</code> 会在操作系统的默认位置下创建该文件。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">f</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">CreateTemp</span><span class="p">(</span><span class="s">""</span><span class="p">,</span> <span class="s">"sample"</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>打印临时文件的名称。
文件名以 <code>os.CreateTemp</code> 函数的第二个参数作为前缀，
剩余的部分会自动生成，以确保并发调用时，生成不重复的文件名。
在类 Unix 操作系统下，临时目录一般是 <code>/tmp</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="s">"Temp file name:"</span><span class="p">,</span> <span class="nx">f</span><span class="p">.</span><span class="nf">Name</span><span class="p">())</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>defer 删除该文件。
尽管操作系统会自动在某个时间清理临时文件，但手动清理是一个好习惯。</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">Remove</span><span class="p">(</span><span class="nx">f</span><span class="p">.</span><span class="nf">Name</span><span class="p">())</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>我们可以向文件写入一些数据。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">_</span><span class="p">,</span> <span class="nx">err</span> <span class="p">=</span> <span class="nx">f</span><span class="p">.</span><span class="nf">Write</span><span class="p">([]</span><span class="kt">byte</span><span class="p">{</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">4</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>如果需要写入多个临时文件，最好是为其创建一个临时 <em>目录</em> 。
<code>os.MkdirTemp</code> 的参数与 <code>CreateTemp</code> 相同，
但是它返回的是一个 <em>目录名</em> ，而不是一个打开的文件。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">dname</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">MkdirTemp</span><span class="p">(</span><span class="s">""</span><span class="p">,</span> <span class="s">"sampledir"</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">"Temp dir name:"</span><span class="p">,</span> <span class="nx">dname</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</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="nx">dname</span><span class="p">)</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>现在，我们可以通过拼接临时目录和临时文件合成完整的临时文件路径，并写入数据。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">fname</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="nx">dname</span><span class="p">,</span> <span class="s">"file1"</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">WriteFile</span><span class="p">(</span><span class="nx">fname</span><span class="p">,</span> <span class="p">[]</span><span class="kt">byte</span><span class="p">{</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">},</span> <span class="mo">0666</span><span class="p">)</span>
<span class="nf">check</span><span class="p">(</span><span class="nx">err</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 temporary-files-and-directories.go
<span class="go">Temp file name: /tmp/sample610887201
</span><span class="go">Temp dir name: /tmp/sampledir898854668</span></pre>
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="testing-and-benchmarking.html">单元测试和基准测试</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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