Android网络编程（六）OkHttp3用法全解析

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相关文章
Android网络编程（一）HTTP协议原理
Android网络编程（二）HttpClient与HttpURLConnection
Android网络编程（三）Volley用法全解析
Android网络编程（四）从源码解析volley
Android网络编程（五）OkHttp2.x用法全解析

前言

上一篇介绍了OkHttp2.x的用法，这一篇文章我们来对照OkHttp2.x版本来看看，OkHttp3使用起来有那些变化。当然，看这篇文章前建议看一下前一篇文章Android网络编程（五）OkHttp2.x用法全解析。

1.使用前准备

Android Studio 配置gradle：

<code class="hljs bash has-numbering">  compile <span class="hljs-string">'com.squareup.okhttp3:okhttp:3.2.0'</span>
  compile <span class="hljs-string">'com.squareup.okio:okio:1.7.0'</span></code><ul style="" class="pre-numbering"><li>1</li><li>2</li></ul>

添加网络权限：

<code class="hljs xml has-numbering">    <span class="hljs-tag"><<span class="hljs-title">uses-permission</span> <span class="hljs-attribute">android:name</span>=<span class="hljs-value">"android.permission.INTERNET"</span>/></span></code><ul style="" class="pre-numbering"><li>1</li></ul>

2.异步GET请求

惯例，请求百度：

<code class="hljs java has-numbering">        <span class="hljs-keyword">private</span> <span class="hljs-keyword">void</span> <span class="hljs-title">getAsynHttp</span>() {
        mOkHttpClient=<span class="hljs-keyword">new</span> OkHttpClient();
        Request.Builder requestBuilder = <span class="hljs-keyword">new</span> Request.Builder().url(<span class="hljs-string">"http://www.baidu.com"</span>);
        <span class="hljs-comment">//可以省略，默认是GET请求</span>
        requestBuilder.method(<span class="hljs-string">"GET"</span>,<span class="hljs-keyword">null</span>);
        Request request = requestBuilder.build();
        Call mcall= mOkHttpClient.newCall(request);
        mcall.enqueue(<span class="hljs-keyword">new</span> Callback() {
            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onFailure</span>(Call call, IOException e) {

            }

            <span class="hljs-annotation">@Override</span>
            <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">onResponse</span>(Call call, Response response) <span class="hljs-keyword">throws</span> IOException {
                <span class="hljs-keyword">if</span> (<span class="hljs-keyword">null</span> != response.cacheResponse()) {
                    String str = response.cacheResponse().toString();
                    Log.i(<span class="hljs-string">"wangshu"</span>, <span class="hljs-string">"cache---"</span> + str);
                } <span class="hljs-keyword">else</span> {
                    response.body().string();
                    String str = response.networkResponse().toString();
                    Log.i(<span class="hljs-string">"wangshu"</span>, <span class="hljs-string">"network---"</span> + str);
                }
                runOnUiThread(<span class="hljs-keyword">new</span> Runnable() {
                    <span class="hljs-annotation">@Override</span>
                    <span class="hljs-keyword">public</span> <span class="hljs-keyword">void</span> <span class="hljs-title">run</span>() {
                        Toast.makeText(getApplicationContext(), <span class="hljs-string">"请求成功"</span>, Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });
    }</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li><li>32</li></ul>

与2.x版本并没有什么不同，比较郁闷的是回调仍然不在UI线程。

2.异步POST请求

OkHttp3异步POST请求和OkHttp2.x有一些差别就是没有FormEncodingBuilder这个类，替代它的是功能更加强大的FormBody：

<code class="hljs vbscript has-numbering">   <span class="hljs-keyword">private</span> void postAsynHttp() {
        mOkHttpClient=<span class="hljs-keyword">new</span> OkHttpClient();
        RequestBody formBody = <span class="hljs-keyword">new</span> FormBody.Builder()
                .add(<span class="hljs-string">"size"</span>, <span class="hljs-string">"10"</span>)
                .build();
        <span class="hljs-built_in">Request</span> <span class="hljs-built_in">request</span> = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Request</span>.Builder()
                .url(<span class="hljs-string">"http://api.1-blog.com/biz/bizserver/article/list.do"</span>)
                .post(formBody)
                .build();
        <span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span> = mOkHttpClient.newCall(<span class="hljs-built_in">request</span>);
        <span class="hljs-keyword">call</span>.enqueue(<span class="hljs-keyword">new</span> Callback() {
            @Override
            <span class="hljs-keyword">public</span> void onFailure(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, IOException e) {

            }

            @Override
            <span class="hljs-keyword">public</span> void onResponse(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, <span class="hljs-built_in">Response</span> <span class="hljs-built_in">response</span>) throws IOException {
                <span class="hljs-built_in">String</span> str = <span class="hljs-built_in">response</span>.body().<span class="hljs-built_in">string</span>();
                <span class="hljs-built_in">Log</span>.i(<span class="hljs-string">"wangshu"</span>, str);

                runOnUiThread(<span class="hljs-keyword">new</span> Runnable() {
                    @Override
                    <span class="hljs-keyword">public</span> void run() {
                        Toast.makeText(getApplicationContext(), <span class="hljs-string">"请求成功"</span>, Toast.LENGTH_SHORT).show();
                    }
                });
            }

        });
    }</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li></ul>

3.异步上传文件

上传文件本身也是一个POST请求，上一篇没有讲，这里我们补上。首先定义上传文件类型：

<code class="hljs java has-numbering">    <span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> MediaType MEDIA_TYPE_MARKDOWN
            = MediaType.parse(<span class="hljs-string">"text/x-markdown; charset=utf-8"</span>);</code><ul style="" class="pre-numbering"><li>1</li><li>2</li></ul>

将sdcard根目录的wangshu.txt文件上传到服务器上：

<code class="hljs vbscript has-numbering">    <span class="hljs-keyword">private</span> void postAsynFile() {
        mOkHttpClient=<span class="hljs-keyword">new</span> OkHttpClient();
        File file = <span class="hljs-keyword">new</span> File(<span class="hljs-string">"/sdcard/wangshu.txt"</span>);
        <span class="hljs-built_in">Request</span> <span class="hljs-built_in">request</span> = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Request</span>.Builder()
                .url(<span class="hljs-string">"https://api.github.com/markdown/raw"</span>)
                .post(RequestBody.create(MEDIA_TYPE_MARKDOWN, file))
                .build();

            mOkHttpClient.newCall(<span class="hljs-built_in">request</span>).enqueue(<span class="hljs-keyword">new</span> Callback() {
                @Override
                <span class="hljs-keyword">public</span> void onFailure(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, IOException e) {

                }

                @Override
                <span class="hljs-keyword">public</span> void onResponse(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, <span class="hljs-built_in">Response</span> <span class="hljs-built_in">response</span>) throws IOException {
                    <span class="hljs-built_in">Log</span>.i(<span class="hljs-string">"wangshu"</span>,<span class="hljs-built_in">response</span>.body().<span class="hljs-built_in">string</span>());
                }
            });
        }
</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li></ul>

当然如果想要改为同步的上传文件只要调用 mOkHttpClient.newCall(request).execute()就可以了。
在wangshu.txt文件中有一行字“Android网络编程（六）OkHttp3用法全解析”我们运行程序点击发送文件按钮，最终请求网络返回的结果就是我们txt文件中的内容 ：

当然不要忘了添加如下权限：

<code class="hljs xml has-numbering">   <span class="hljs-tag"><<span class="hljs-title">uses-permission</span> <span class="hljs-attribute">android:name</span>=<span class="hljs-value">"android.permission.READ_EXTERNAL_STORAGE"</span>/></span>
   <span class="hljs-tag"><<span class="hljs-title">uses-permission</span> <span class="hljs-attribute">android:name</span>=<span class="hljs-value">"android.permission.WRITE_EXTERNAL_STORAGE"</span>/></span></code><ul style="" class="pre-numbering"><li>1</li><li>2</li></ul>

4.异步下载文件

下载文件同样在上一篇没有讲到，实现起来比较简单，在这里下载一张图片，我们得到Response后将流写进我们指定的图片文件中就可以了。

<code class="hljs vbscript has-numbering">    <span class="hljs-keyword">private</span> void downAsynFile() {
        mOkHttpClient = <span class="hljs-keyword">new</span> OkHttpClient();
        <span class="hljs-built_in">String</span> url = <span class="hljs-string">"https://img-my.youkuaiyun.com/uploads/201603/26/1458988468_5804.jpg"</span>;
        <span class="hljs-built_in">Request</span> <span class="hljs-built_in">request</span> = <span class="hljs-keyword">new</span> <span class="hljs-built_in">Request</span>.Builder().url(url).build();
        mOkHttpClient.newCall(<span class="hljs-built_in">request</span>).enqueue(<span class="hljs-keyword">new</span> Callback() {
            @Override
            <span class="hljs-keyword">public</span> void onFailure(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, IOException e) {

            }

            @Override
            <span class="hljs-keyword">public</span> void onResponse(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, <span class="hljs-built_in">Response</span> <span class="hljs-built_in">response</span>) {
                InputStream inputStream = <span class="hljs-built_in">response</span>.body().byteStream();
                FileOutputStream fileOutputStream = <span class="hljs-literal">null</span>;
                try {
                    fileOutputStream = <span class="hljs-keyword">new</span> FileOutputStream(<span class="hljs-keyword">new</span> File(<span class="hljs-string">"/sdcard/wangshu.jpg"</span>));
                    byte[] buffer = <span class="hljs-keyword">new</span> byte[<span class="hljs-number">2048</span>];
                    <span class="hljs-built_in">int</span> <span class="hljs-built_in">len</span> = <span class="hljs-number">0</span>;
                    <span class="hljs-keyword">while</span> ((<span class="hljs-built_in">len</span> = inputStream.read(buffer)) != -<span class="hljs-number">1</span>) {
                        fileOutputStream.write(buffer, <span class="hljs-number">0</span>, <span class="hljs-built_in">len</span>);
                    }
                    fileOutputStream.flush();
                } catch (IOException e) {
                    <span class="hljs-built_in">Log</span>.i(<span class="hljs-string">"wangshu"</span>, <span class="hljs-string">"IOException"</span>);
                    e.printStackTrace();
               }

               <span class="hljs-built_in">Log</span>.d(<span class="hljs-string">"wangshu"</span>, <span class="hljs-string">"文件下载成功"</span>);
           }
       });
   }</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li><li>28</li><li>29</li><li>30</li><li>31</li></ul>

5.异步上传Multipart文件

这种场景很常用，我们有时会上传文件同时还需要传其他类型的字段，OkHttp3实现起来很简单，需要注意的是没有服务器接收我这个Multipart文件，所以这里只是举个例子，具体的应用还要结合实际工作中对应的服务器。
首先定义上传文件类型：

<code class="hljs java has-numbering"><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">final</span> MediaType MEDIA_TYPE_PNG = MediaType.parse(<span class="hljs-string">"image/png"</span>);</code><ul style="" class="pre-numbering"><li>1</li></ul>

<code class="hljs avrasm has-numbering">private void sendMultipart(){
    mOkHttpClient = new OkHttpClient()<span class="hljs-comment">;</span>
    RequestBody requestBody = new MultipartBody<span class="hljs-preprocessor">.Builder</span>()
            <span class="hljs-preprocessor">.setType</span>(MultipartBody<span class="hljs-preprocessor">.FORM</span>)
            <span class="hljs-preprocessor">.addFormDataPart</span>(<span class="hljs-string">"title"</span>, <span class="hljs-string">"wangshu"</span>)
            <span class="hljs-preprocessor">.addFormDataPart</span>(<span class="hljs-string">"image"</span>, <span class="hljs-string">"wangshu.jpg"</span>,
                    RequestBody<span class="hljs-preprocessor">.create</span>(MEDIA_TYPE_PNG, new File(<span class="hljs-string">"/sdcard/wangshu.jpg"</span>)))
            <span class="hljs-preprocessor">.build</span>()<span class="hljs-comment">;</span>

    Request request = new Request<span class="hljs-preprocessor">.Builder</span>()
            <span class="hljs-preprocessor">.header</span>(<span class="hljs-string">"Authorization"</span>, <span class="hljs-string">"Client-ID "</span> + <span class="hljs-string">"..."</span>)
            <span class="hljs-preprocessor">.url</span>(<span class="hljs-string">"https://api.imgur.com/3/image"</span>)
            <span class="hljs-preprocessor">.post</span>(requestBody)
            <span class="hljs-preprocessor">.build</span>()<span class="hljs-comment">;</span>

   mOkHttpClient<span class="hljs-preprocessor">.newCall</span>(request)<span class="hljs-preprocessor">.enqueue</span>(new Callback() {
       @Override
       public void onFailure(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, IOException e) {

       }

       @Override
       public void onResponse(<span class="hljs-keyword">Call</span> <span class="hljs-keyword">call</span>, Response response) throws IOException {
           Log<span class="hljs-preprocessor">.i</span>(<span class="hljs-string">"wangshu"</span>, response<span class="hljs-preprocessor">.body</span>()<span class="hljs-preprocessor">.string</span>())<span class="hljs-comment">;</span>
       }
   })<span class="hljs-comment">;</span>
}</code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li><li>11</li><li>12</li><li>13</li><li>14</li><li>15</li><li>16</li><li>17</li><li>18</li><li>19</li><li>20</li><li>21</li><li>22</li><li>23</li><li>24</li><li>25</li><li>26</li><li>27</li></ul>

6.设置超时时间和缓存

和OkHttp2.x有区别的是不能通过OkHttpClient直接设置超时时间和缓存了，而是通过OkHttpClient.Builder来设置，通过builder配置好OkHttpClient后用builder.build()来返回OkHttpClient，所以我们通常不会调用new OkHttpClient()来得到OkHttpClient，而是通过builder.build()：

<code class="hljs avrasm has-numbering">        File sdcache = getExternalCacheDir()<span class="hljs-comment">;</span>
        int cacheSize = <span class="hljs-number">10</span> * <span class="hljs-number">1024</span> * <span class="hljs-number">1024</span><span class="hljs-comment">;</span>
        OkHttpClient<span class="hljs-preprocessor">.Builder</span> builder = new OkHttpClient<span class="hljs-preprocessor">.Builder</span>()
                <span class="hljs-preprocessor">.connectTimeout</span>(<span class="hljs-number">15</span>, TimeUnit<span class="hljs-preprocessor">.SECONDS</span>)
                <span class="hljs-preprocessor">.writeTimeout</span>(<span class="hljs-number">20</span>, TimeUnit<span class="hljs-preprocessor">.SECONDS</span>)
                <span class="hljs-preprocessor">.readTimeout</span>(<span class="hljs-number">20</span>, TimeUnit<span class="hljs-preprocessor">.SECONDS</span>)
                <span class="hljs-preprocessor">.cache</span>(new Cache(sdcache<span class="hljs-preprocessor">.getAbsoluteFile</span>(), cacheSize))<span class="hljs-comment">;</span>
        OkHttpClient mOkHttpClient=builder<span class="hljs-preprocessor">.build</span>()<span class="hljs-comment">;            </span></code><ul style="" class="pre-numbering"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li></ul>

7.关于取消请求和封装

取消请求仍旧可以调用call.cancel()，这个没有变化，不明白的可以查看上一篇文章Android网络编程（五）OkHttp2.x用法全解析，这里就不赘述了，封装上一篇也讲过仍旧推荐OkHttpFinal，它目前是基于OkHttp3来进行封装的。

8.关于源码Demo

源码Demo很简单就四个按钮用来测试上面讲到的内容：

github源码下载