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<ol class="chapter">
<li class="chapter-item expanded ">
<a href="../index.html" >Go语言圣经</a>
</li>
<li class="chapter-item expanded ">
<a href="../preface-zh.html" >译者序</a>
</li>
<li class="chapter-item expanded ">
<a href="../preface.html" >前言</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1.html" ><strong aria-hidden="true">1.</strong> 入门</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch1/ch1-01.html" ><strong aria-hidden="true">1.1.</strong> Hello, World</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-02.html" ><strong aria-hidden="true">1.2.</strong> 命令行参数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-03.html" ><strong aria-hidden="true">1.3.</strong> 查找重复的行</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-04.html" ><strong aria-hidden="true">1.4.</strong> GIF动画</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-05.html" ><strong aria-hidden="true">1.5.</strong> 获取URL</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-06.html" ><strong aria-hidden="true">1.6.</strong> 并发获取多个URL</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-07.html" ><strong aria-hidden="true">1.7.</strong> Web服务</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch1/ch1-08.html" ><strong aria-hidden="true">1.8.</strong> 本章要点</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch2/ch2.html" ><strong aria-hidden="true">2.</strong> 程序结构</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch2/ch2-01.html" ><strong aria-hidden="true">2.1.</strong> 命名</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-02.html" ><strong aria-hidden="true">2.2.</strong> 声明</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-03.html" ><strong aria-hidden="true">2.3.</strong> 变量</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-04.html" ><strong aria-hidden="true">2.4.</strong> 赋值</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-05.html" ><strong aria-hidden="true">2.5.</strong> 类型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-06.html" ><strong aria-hidden="true">2.6.</strong> 包和文件</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch2/ch2-07.html" ><strong aria-hidden="true">2.7.</strong> 作用域</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch3/ch3.html" ><strong aria-hidden="true">3.</strong> 基础数据类型</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch3/ch3-01.html" ><strong aria-hidden="true">3.1.</strong> 整型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch3/ch3-02.html" ><strong aria-hidden="true">3.2.</strong> 浮点数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch3/ch3-03.html" ><strong aria-hidden="true">3.3.</strong> 复数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch3/ch3-04.html" ><strong aria-hidden="true">3.4.</strong> 布尔型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch3/ch3-05.html" ><strong aria-hidden="true">3.5.</strong> 字符串</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch3/ch3-06.html" ><strong aria-hidden="true">3.6.</strong> 常量</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch4/ch4.html" ><strong aria-hidden="true">4.</strong> 复合数据类型</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch4/ch4-01.html" ><strong aria-hidden="true">4.1.</strong> 数组</a>
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<li class="chapter-item expanded ">
<a href="../ch4/ch4-02.html" ><strong aria-hidden="true">4.2.</strong> Slice</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch4/ch4-03.html" ><strong aria-hidden="true">4.3.</strong> Map</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch4/ch4-04.html" ><strong aria-hidden="true">4.4.</strong> 结构体</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch4/ch4-05.html" ><strong aria-hidden="true">4.5.</strong> JSON</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch4/ch4-06.html" ><strong aria-hidden="true">4.6.</strong> 文本和HTML模板</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch5/ch5.html" ><strong aria-hidden="true">5.</strong> 函数</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch5/ch5-01.html" ><strong aria-hidden="true">5.1.</strong> 函数声明</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-02.html" ><strong aria-hidden="true">5.2.</strong> 递归</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-03.html" ><strong aria-hidden="true">5.3.</strong> 多返回值</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-04.html" ><strong aria-hidden="true">5.4.</strong> 错误</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-05.html" ><strong aria-hidden="true">5.5.</strong> 函数值</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-06.html" ><strong aria-hidden="true">5.6.</strong> 匿名函数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-07.html" ><strong aria-hidden="true">5.7.</strong> 可变参数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-08.html" ><strong aria-hidden="true">5.8.</strong> Deferred函数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-09.html" ><strong aria-hidden="true">5.9.</strong> Panic异常</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch5/ch5-10.html" ><strong aria-hidden="true">5.10.</strong> Recover捕获异常</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch6/ch6.html" ><strong aria-hidden="true">6.</strong> 方法</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch6/ch6-01.html" ><strong aria-hidden="true">6.1.</strong> 方法声明</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch6/ch6-02.html" ><strong aria-hidden="true">6.2.</strong> 基于指针对象的方法</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch6/ch6-03.html" ><strong aria-hidden="true">6.3.</strong> 通过嵌入结构体来扩展类型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch6/ch6-04.html" ><strong aria-hidden="true">6.4.</strong> 方法值和方法表达式</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch6/ch6-05.html" ><strong aria-hidden="true">6.5.</strong> 示例: Bit数组</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch6/ch6-06.html" ><strong aria-hidden="true">6.6.</strong> 封装</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch7/ch7.html" ><strong aria-hidden="true">7.</strong> 接口</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch7/ch7-01.html" ><strong aria-hidden="true">7.1.</strong> 接口是合约</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-02.html" ><strong aria-hidden="true">7.2.</strong> 接口类型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-03.html" ><strong aria-hidden="true">7.3.</strong> 实现接口的条件</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-04.html" ><strong aria-hidden="true">7.4.</strong> flag.Value接口</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-05.html" ><strong aria-hidden="true">7.5.</strong> 接口值</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-06.html" ><strong aria-hidden="true">7.6.</strong> sort.Interface接口</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-07.html" ><strong aria-hidden="true">7.7.</strong> http.Handler接口</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-08.html" ><strong aria-hidden="true">7.8.</strong> error接口</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-09.html" ><strong aria-hidden="true">7.9.</strong> 示例: 表达式求值</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-10.html" ><strong aria-hidden="true">7.10.</strong> 类型断言</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-11.html" ><strong aria-hidden="true">7.11.</strong> 基于类型断言识别错误类型</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-12.html" ><strong aria-hidden="true">7.12.</strong> 通过类型断言查询接口</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-13.html" ><strong aria-hidden="true">7.13.</strong> 类型分支</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-14.html" ><strong aria-hidden="true">7.14.</strong> 示例: 基于标记的XML解码</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch7/ch7-15.html" ><strong aria-hidden="true">7.15.</strong> 补充几点</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch8/ch8.html" ><strong aria-hidden="true">8.</strong> Goroutines和Channels</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch8/ch8-01.html" ><strong aria-hidden="true">8.1.</strong> Goroutines</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-02.html" ><strong aria-hidden="true">8.2.</strong> 示例: 并发的Clock服务</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-03.html" ><strong aria-hidden="true">8.3.</strong> 示例: 并发的Echo服务</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-04.html" ><strong aria-hidden="true">8.4.</strong> Channels</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-05.html" ><strong aria-hidden="true">8.5.</strong> 并发的循环</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-06.html" ><strong aria-hidden="true">8.6.</strong> 示例: 并发的Web爬虫</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-07.html" ><strong aria-hidden="true">8.7.</strong> 基于select的多路复用</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-08.html" ><strong aria-hidden="true">8.8.</strong> 示例: 并发的目录遍历</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-09.html" ><strong aria-hidden="true">8.9.</strong> 并发的退出</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch8/ch8-10.html" ><strong aria-hidden="true">8.10.</strong> 示例: 聊天服务</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch9/ch9.html" ><strong aria-hidden="true">9.</strong> 基于共享变量的并发</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch9/ch9-01.html" ><strong aria-hidden="true">9.1.</strong> 竞争条件</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-02.html" ><strong aria-hidden="true">9.2.</strong> sync.Mutex互斥锁</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-03.html" ><strong aria-hidden="true">9.3.</strong> sync.RWMutex读写锁</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-04.html" ><strong aria-hidden="true">9.4.</strong> 内存同步</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-05.html" ><strong aria-hidden="true">9.5.</strong> sync.Once惰性初始化</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-06.html" ><strong aria-hidden="true">9.6.</strong> 竞争条件检测</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-07.html" ><strong aria-hidden="true">9.7.</strong> 示例: 并发的非阻塞缓存</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch9/ch9-08.html" ><strong aria-hidden="true">9.8.</strong> Goroutines和线程</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch10/ch10.html" ><strong aria-hidden="true">10.</strong> 包和工具</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch10/ch10-01.html" ><strong aria-hidden="true">10.1.</strong> 包简介</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-02.html" ><strong aria-hidden="true">10.2.</strong> 导入路径</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-03.html" ><strong aria-hidden="true">10.3.</strong> 包声明</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-04.html" class="active"><strong aria-hidden="true">10.4.</strong> 导入声明</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-05.html" ><strong aria-hidden="true">10.5.</strong> 包的匿名导入</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-06.html" ><strong aria-hidden="true">10.6.</strong> 包和命名</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch10/ch10-07.html" ><strong aria-hidden="true">10.7.</strong> 工具</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch11/ch11.html" ><strong aria-hidden="true">11.</strong> 测试</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch11/ch11-01.html" ><strong aria-hidden="true">11.1.</strong> go test</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch11/ch11-02.html" ><strong aria-hidden="true">11.2.</strong> 测试函数</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch11/ch11-03.html" ><strong aria-hidden="true">11.3.</strong> 测试覆盖率</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch11/ch11-04.html" ><strong aria-hidden="true">11.4.</strong> 基准测试</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch11/ch11-05.html" ><strong aria-hidden="true">11.5.</strong> 剖析</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch11/ch11-06.html" ><strong aria-hidden="true">11.6.</strong> 示例函数</a>
</li>
</ol>
<li class="chapter-item expanded ">
<a href="../ch12/ch12.html" ><strong aria-hidden="true">12.</strong> 反射</a>
</li>
<ol class="section">
<li class="chapter-item expanded ">
<a href="../ch12/ch12-01.html" ><strong aria-hidden="true">12.1.</strong> 为何需要反射?</a>
</li>
<li class="chapter-item expanded ">
<a href="../ch12/ch12-02.html" ><strong aria-hidden="true">12.2.</strong> reflect.Type和reflect.Value</a>
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<a href="../ch12/ch12-06.html" ><strong aria-hidden="true">12.6.</strong> 示例: 解码S表达式</a>
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<a href="../ch12/ch12-07.html" ><strong aria-hidden="true">12.7.</strong> 获取结构体字段标签</a>
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<a href="../ch12/ch12-08.html" ><strong aria-hidden="true">12.8.</strong> 显示一个类型的方法集</a>
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<a href="../ch12/ch12-09.html" ><strong aria-hidden="true">12.9.</strong> 几点忠告</a>
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<a href="../ch13/ch13-02.html" ><strong aria-hidden="true">13.2.</strong> unsafe.Pointer</a>
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<a href="../ch13/ch13-04.html" ><strong aria-hidden="true">13.4.</strong> 通过cgo调用C代码</a>
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<ul dir="auto"><li><em>凹语言(Go实现, 面向WASM设计): <a href="https://github.com/wa-lang/wa">https://github.com/wa-lang/wa</a></em></li><li><em>WaBook(Go语言实现的MD电子书构建工具): <a href="https://github.com/wa-lang/wabook">https://github.com/wa-lang/wabook</a></em></li></ul><hr>
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<h2>10.4. 导入声明</h2>
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<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>
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<pre><code class="language-Go">import &quot;fmt&quot;
import &quot;os&quot;
import (
&quot;fmt&quot;
&quot;os&quot;
)
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</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>
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<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;
)
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</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>
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<pre><code class="language-Go">import (
&quot;crypto/rand&quot;
mrand &quot;math/rand&quot; // alternative name mrand avoids conflict
)
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</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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