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<hr>
<h2 id="104-导入声明"><a class="header" href="#104-导入声明">10.4. 导入声明</a></h2>
<p>可以在一个Go语言源文件包声明语句之后，其它非导入声明语句之前，包含零到多个导入包声明语句。每个导入声明可以单独指定一个导入路径，也可以通过圆括号同时导入多个导入路径。下面两个导入形式是等价的，但是第二种形式更为常见。</p>
<pre><code class="language-Go">import &quot;fmt&quot;
import &quot;os&quot;
import (
&quot;fmt&quot;
&quot;os&quot;
)
</code></pre>
<p>导入的包之间可以通过添加空行来分组；通常将来自不同组织的包独自分组。包的导入顺序无关紧要，但是在每个分组中一般会根据字符串顺序排列。（gofmt和goimports工具都可以将不同分组导入的包独立排序。）</p>
<pre><code class="language-Go">import (
&quot;fmt&quot;
&quot;html/template&quot;
&quot;os&quot;
&quot;golang.org/x/net/html&quot;
&quot;golang.org/x/net/ipv4&quot;
)
</code></pre>
<p>如果我们想同时导入两个有着名字相同的包，例如math/rand包和crypto/rand包，那么导入声明必须至少为一个同名包指定一个新的包名以避免冲突。这叫做导入包的重命名。</p>
<pre><code class="language-Go">import (
&quot;crypto/rand&quot;
mrand &quot;math/rand&quot; // alternative name mrand avoids conflict
)
</code></pre>
<p>导入包的重命名只影响当前的源文件。其它的源文件如果导入了相同的包，可以用导入包原本默认的名字或重命名为另一个完全不同的名字。</p>
<p>导入包重命名是一个有用的特性，它不仅仅只是为了解决名字冲突。如果导入的一个包名很笨重，特别是在一些自动生成的代码中，这时候用一个简短名称会更方便。选择用简短名称重命名导入包时候最好统一，以避免包名混乱。选择另一个包名称还可以帮助避免和本地普通变量名产生冲突。例如，如果文件中已经有了一个名为path的变量，那么我们可以将“path”标准包重命名为pathpkg。</p>
<p>每个导入声明语句都明确指定了当前包和被导入包之间的依赖关系。如果遇到包循环导入的情况，Go语言的构建工具将报告错误。</p>
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