Android OkHttp完全解析 是时候来了解OkHttp了

jopen 9年前

转载请标明出处：
http://blog.csdn.net/lmj623565791/article/details/47911083；
本文出自:【张鸿洋的博客】

一、概述

最近在群里听到各种讨论okhttp的话题，可见okhttp的口碑相当好了。再加上Google貌似在6.0版本里面删除了HttpClient相关API，对于这个行为不做评价。为了更好的在应对网络访问，学习下okhttp还是蛮必要的，本篇博客首先介绍okhttp的简单使用，主要包含：

  • 一般的get请求
  • 一般的post请求
  • 基于Http的文件上传
  • 文件下载
  • 加载图片
  • 支持请求回调，直接返回对象、对象集合
  • 支持session的保持

最后会对上述几个功能进行封装，完整的封装类的地址见：https://github.com/hongyangAndroid/okhttp-utils

使用前，对于Android Studio的用户，可以选择添加:

compile 'com.squareup.okhttp:okhttp:2.4.0'

或者Eclipse的用户，可以下载最新的jar okhttp he latest JAR ，添加依赖就可以用了。

注意:okhttp内部依赖okio，别忘了同时导入okio：

gradle: compile 'com.squareup.okio:okio:1.5.0'

最新的jar地址：okio the latest JAR

二、使用教程

（一）Http Get

对了网络加载库，那么最常见的肯定就是http get请求了，比如获取一个网页的内容。

//创建okHttpClient对象  OkHttpClient mOkHttpClient = new OkHttpClient();  //创建一个Request  final Request request = new Request.Builder()                  .url("https://github.com/hongyangAndroid")                  .build();  //new call  Call call = mOkHttpClient.newCall(request);   //请求加入调度  call.enqueue(new Callback()          {              @Override              public void onFailure(Request request, IOException e)              {              }                @Override              public void onResponse(final Response response) throws IOException              {                      //String htmlStr = response.body().string();              }          });

  1. 以上就是发送一个get请求的步骤，首先构造一个Request对象，参数最起码有个url，当然你可以通过Request.Builder设置更多的参数比如：header、method等。

  2. 然后通过request的对象去构造得到一个Call对象，类似于将你的请求封装成了任务，既然是任务，就会有execute()和cancel()等方法。

  3. 最后，我们希望以异步的方式去执行请求，所以我们调用的是call.enqueue，将call加入调度队列，然后等待任务执行完成，我们在Callback中即可得到结果。

看到这，你会发现，整体的写法还是比较长的，所以封装肯定是要做的，不然每个请求这么写，得累死。

ok，需要注意几点：

  • onResponse回调的参数是response，一般情况下，比如我们希望获得返回的字符串，可以通过response.body().string()获取；如果希望获得返回的二进制字节数组，则调用response.body().bytes()；如果你想拿到返回的inputStream，则调用response.body().byteStream()

    看到这，你可能会奇怪，竟然还能拿到返回的inputStream，看到这个最起码能意识到一点，这里支持大文件下载，有inputStream我们就可以通过IO的方式写文件。不过也说明一个问题，这个onResponse执行的线程并不是UI线程。的确是的，如果你希望操作控件，还是需要使用handler等，例如：

    @Override  public void onResponse(final Response response) throws IOException  {        final String res = response.body().string();        runOnUiThread(new Runnable()        {            @Override            public void run()            {              mTv.setText(res);            }          });  }
  • 我们这里是异步的方式去执行，当然也支持阻塞的方式，上面我们也说了Call有一个execute()方法，你也可以直接调用call.execute()通过返回一个Response。

(二) Http Post 携带参数

看来上面的简单的get请求，基本上整个的用法也就掌握了，比如post携带参数，也仅仅是Request的构造的不同。

Request request = buildMultipartFormRequest(          url, new File[]{file}, new String[]{fileKey}, null);  FormEncodingBuilder builder = new FormEncodingBuilder();     builder.add("username","张鸿洋");    Request request = new Request.Builder()                     .url(url)                  .post(builder.build())                  .build();   mOkHttpClient.newCall(request).enqueue(new Callback(){});

大家都清楚，post的时候，参数是包含在请求体中的；所以我们通过FormEncodingBuilder。添加多个String键值对，然后去构造RequestBody，最后完成我们Request的构造。

后面的就和上面一样了。

（三）基于Http的文件上传

接下来我们在介绍一个可以构造RequestBody的Builder，叫做MultipartBuilder。当我们需要做类似于表单上传的时候，就可以使用它来构造我们的requestBody。

File file = new File(Environment.getExternalStorageDirectory(), "balabala.mp4");    RequestBody fileBody = RequestBody.create(MediaType.parse("application/octet-stream"), file);    RequestBody requestBody = new MultipartBuilder()       .type(MultipartBuilder.FORM)       .addPart(Headers.of(            "Content-Disposition",                 "form-data; name=\"username\""),             RequestBody.create(null, "张鸿洋"))       .addPart(Headers.of(           "Content-Disposition",            "form-data; name=\"mFile\"; filename=\"wjd.mp4\""), fileBody)       .build();    Request request = new Request.Builder()      .url("http://192.168.1.103:8080/okHttpServer/fileUpload")      .post(requestBody)      .build();    Call call = mOkHttpClient.newCall(request);  call.enqueue(new Callback()  {      //...  });

上述代码向服务器传递了一个键值对username:张鸿洋和一个文件。我们通过MultipartBuilder的addPart方法可以添加键值对或者文件。

其实类似于我们拼接模拟浏览器行为的方式，如果你对这块不了解，可以参考：从原理角度解析Android （Java） http 文件上传

ok，对于我们最开始的目录还剩下图片下载，文件下载；这两个一个是通过回调的Response拿到byte[]然后decode成图片；文件下载，就是拿到inputStream做写文件操作，我们这里就不赘述了。

关于用法，也可以参考泡网OkHttp使用教程

接下来我们主要看如何封装上述的代码。

三、封装

由于按照上述的代码，写多个请求肯定包含大量的重复代码，所以我希望封装后的代码调用是这样的：

（一）使用

  1. 一般的get请求

     OkHttpClientManager.getAsyn("https://www.baidu.com", new OkHttpClientManager.ResultCallback<String>()          {              @Override              public void onError(Request request, Exception e)              {                  e.printStackTrace();              }                @Override              public void onResponse(String u)              {                  mTv.setText(u);//注意这里是UI线程              }          });

    对于一般的请求，我们希望给个url，然后CallBack里面直接操作控件。

  2. 文件上传且携带参数

    我们希望提供一个方法，传入url,params,file,callback即可。

      OkHttpClientManager.postAsyn("http://192.168.1.103:8080/okHttpServer/fileUpload",//      new OkHttpClientManager.ResultCallback<String>()      {          @Override          public void onError(Request request, IOException e)          {              e.printStackTrace();          }            @Override          public void onResponse(String result)          {            }      },//      file,//      "mFile",//      new OkHttpClientManager.Param[]{              new OkHttpClientManager.Param("username", "zhy"),              new OkHttpClientManager.Param("password", "123")}          );

    键值对没什么说的，参数3为file，参数4为file对应的name，这个name不是文件的名字；
    对应于http中的

    <input type="file" name="mFile" >

    对应的是name后面的值，即mFile.

  3. 文件下载

    对于文件下载，提供url，目标dir，callback即可。

    OkHttpClientManager.downloadAsyn(      "http://192.168.1.103:8080/okHttpServer/files/messenger_01.png",          Environment.getExternalStorageDirectory().getAbsolutePath(),   new OkHttpClientManager.ResultCallback<String>()      {          @Override          public void onError(Request request, IOException e)          {            }            @Override          public void onResponse(String response)          {              //文件下载成功，这里回调的reponse为文件的absolutePath          }  });

  4. 展示图片

    展示图片，我们希望提供一个url和一个imageview，如果下载成功，直接帮我们设置上即可。

     OkHttpClientManager.displayImage(mImageView,        "http://images.csdn.net/20150817/1.jpg");

    内部会自动根据imageview的大小自动对图片进行合适的压缩。虽然，这里可能不适合一次性加载大量图片的场景，但是对于app中偶尔有几个图片的加载，还是可用的。

四、整合Gson

很多人提出项目中使用时，服务端返回的是Json字符串，希望客户端回调可以直接拿到对象，于是整合进入了Gson，完善该功能。

（一）直接回调对象

例如现在有个User实体类：

package com.zhy.utils.http.okhttp;    public class User {        public String username ;       public String password  ;        public User() {          // TODO Auto-generated constructor stub      }        public User(String username, String password) {          this.username = username;          this.password = password;      }        @Override      public String toString()      {          return "User{" +                  "username='" + username + '\'' +                  ", password='" + password + '\'' +                  '}';      }  }

服务端返回：

{"username":"zhy","password":"123"}

客户端可以如下方式调用：

 OkHttpClientManager.getAsyn("http://192.168.56.1:8080/okHttpServer/user!getUser",  new OkHttpClientManager.ResultCallback<User>()  {      @Override      public void onError(Request request, Exception e)      {          e.printStackTrace();      }        @Override      public void onResponse(User user)      {          mTv.setText(u.toString());//UI线程      }  });

我们传入泛型User，在onResponse里面直接回调User对象。
这里特别要注意的事，如果在json字符串->实体对象过程中发生错误，程序不会崩溃，onError方法会被回调。

注意：这里做了少许的更新，接口命名从StringCallback修改为ResultCallback。接口中的onFailure方法修改为onError。

(二) 回调对象集合

依然是上述的User类，服务端返回

[{"username":"zhy","password":"123"},{"username":"lmj","password":"12345"}]

则客户端可以如下调用：

OkHttpClientManager.getAsyn("http://192.168.56.1:8080/okHttpServer/user!getUsers",  new OkHttpClientManager.ResultCallback<List<User>>()  {      @Override      public void onError(Request request, Exception e)      {          e.printStackTrace();      }      @Override      public void onResponse(List<User> us)      {          Log.e("TAG", us.size() + "");          mTv.setText(us.get(1).toString());      }  });

唯一的区别，就是泛型变为List<User> ，ok ， 如果发现bug或者有任何意见欢迎留言。

源码

ok，基本介绍完了，对于封装的代码其实也很简单，我就直接贴出来了，因为也没什么好介绍的，如果你看完上面的用法，肯定可以看懂：

package com.zhy.utils.http.okhttp;    import android.graphics.Bitmap;  import android.graphics.BitmapFactory;  import android.os.Handler;  import android.os.Looper;  import android.widget.ImageView;    import com.google.gson.Gson;  import com.google.gson.internal.$Gson$Types;  import com.squareup.okhttp.Call;  import com.squareup.okhttp.Callback;  import com.squareup.okhttp.FormEncodingBuilder;  import com.squareup.okhttp.Headers;  import com.squareup.okhttp.MediaType;  import com.squareup.okhttp.MultipartBuilder;  import com.squareup.okhttp.OkHttpClient;  import com.squareup.okhttp.Request;  import com.squareup.okhttp.RequestBody;  import com.squareup.okhttp.Response;    import java.io.File;  import java.io.FileOutputStream;  import java.io.IOException;  import java.io.InputStream;  import java.lang.reflect.ParameterizedType;  import java.lang.reflect.Type;  import java.net.CookieManager;  import java.net.CookiePolicy;  import java.net.FileNameMap;  import java.net.URLConnection;  import java.util.HashMap;  import java.util.Map;  import java.util.Set;    /** * Created by zhy on 15/8/17. */  public class OkHttpClientManager {      private static OkHttpClientManager mInstance;      private OkHttpClient mOkHttpClient;      private Handler mDelivery;      private Gson mGson;          private static final String TAG = "OkHttpClientManager";        private OkHttpClientManager()      {          mOkHttpClient = new OkHttpClient();          //cookie enabled          mOkHttpClient.setCookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_ORIGINAL_SERVER));          mDelivery = new Handler(Looper.getMainLooper());          mGson = new Gson();      }        public static OkHttpClientManager getInstance()      {          if (mInstance == null)          {              synchronized (OkHttpClientManager.class)              {                  if (mInstance == null)                  {                      mInstance = new OkHttpClientManager();                  }              }          }          return mInstance;      }        /** * 同步的Get请求 * * @param url * @return Response */      private Response _getAsyn(String url) throws IOException      {          final Request request = new Request.Builder()                  .url(url)                  .build();          Call call = mOkHttpClient.newCall(request);          Response execute = call.execute();          return execute;      }        /** * 同步的Get请求 * * @param url * @return 字符串 */      private String _getAsString(String url) throws IOException      {          Response execute = _getAsyn(url);          return execute.body().string();      }          /** * 异步的get请求 * * @param url * @param callback */      private void _getAsyn(String url, final ResultCallback callback)      {          final Request request = new Request.Builder()                  .url(url)                  .build();          deliveryResult(callback, request);      }          /** * 同步的Post请求 * * @param url * @param params post的参数 * @return */      private Response _post(String url, Param... params) throws IOException      {          Request request = buildPostRequest(url, params);          Response response = mOkHttpClient.newCall(request).execute();          return response;      }          /** * 同步的Post请求 * * @param url * @param params post的参数 * @return 字符串 */      private String _postAsString(String url, Param... params) throws IOException      {          Response response = _post(url, params);          return response.body().string();      }        /** * 异步的post请求 * * @param url * @param callback * @param params */      private void _postAsyn(String url, final ResultCallback callback, Param... params)      {          Request request = buildPostRequest(url, params);          deliveryResult(callback, request);      }        /** * 异步的post请求 * * @param url * @param callback * @param params */      private void _postAsyn(String url, final ResultCallback callback, Map<String, String> params)      {          Param[] paramsArr = map2Params(params);          Request request = buildPostRequest(url, paramsArr);          deliveryResult(callback, request);      }        /** * 同步基于post的文件上传 * * @param params * @return */      private Response _post(String url, File[] files, String[] fileKeys, Param... params) throws IOException      {          Request request = buildMultipartFormRequest(url, files, fileKeys, params);          return mOkHttpClient.newCall(request).execute();      }        private Response _post(String url, File file, String fileKey) throws IOException      {          Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, null);          return mOkHttpClient.newCall(request).execute();      }        private Response _post(String url, File file, String fileKey, Param... params) throws IOException      {          Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, params);          return mOkHttpClient.newCall(request).execute();      }        /** * 异步基于post的文件上传 * * @param url * @param callback * @param files * @param fileKeys * @throws IOException */      private void _postAsyn(String url, ResultCallback callback, File[] files, String[] fileKeys, Param... params) throws IOException      {          Request request = buildMultipartFormRequest(url, files, fileKeys, params);          deliveryResult(callback, request);      }        /** * 异步基于post的文件上传，单文件不带参数上传 * * @param url * @param callback * @param file * @param fileKey * @throws IOException */      private void _postAsyn(String url, ResultCallback callback, File file, String fileKey) throws IOException      {          Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, null);          deliveryResult(callback, request);      }        /** * 异步基于post的文件上传，单文件且携带其他form参数上传 * * @param url * @param callback * @param file * @param fileKey * @param params * @throws IOException */      private void _postAsyn(String url, ResultCallback callback, File file, String fileKey, Param... params) throws IOException      {          Request request = buildMultipartFormRequest(url, new File[]{file}, new String[]{fileKey}, params);          deliveryResult(callback, request);      }        /** * 异步下载文件 * * @param url * @param destFileDir 本地文件存储的文件夹 * @param callback */      private void _downloadAsyn(final String url, final String destFileDir, final ResultCallback callback)      {          final Request request = new Request.Builder()                  .url(url)                  .build();          final Call call = mOkHttpClient.newCall(request);          call.enqueue(new Callback()          {              @Override              public void onFailure(final Request request, final IOException e)              {                  sendFailedStringCallback(request, e, callback);              }                @Override              public void onResponse(Response response)              {                  InputStream is = null;                  byte[] buf = new byte[2048];                  int len = 0;                  FileOutputStream fos = null;                  try                  {                      is = response.body().byteStream();                      File file = new File(destFileDir, getFileName(url));                      fos = new FileOutputStream(file);                      while ((len = is.read(buf)) != -1)                      {                          fos.write(buf, 0, len);                      }                      fos.flush();                      //如果下载文件成功，第一个参数为文件的绝对路径                      sendSuccessResultCallback(file.getAbsolutePath(), callback);                  } catch (IOException e)                  {                      sendFailedStringCallback(response.request(), e, callback);                  } finally                  {                      try                      {                          if (is != null) is.close();                      } catch (IOException e)                      {                      }                      try                      {                          if (fos != null) fos.close();                      } catch (IOException e)                      {                      }                  }                }          });      }        private String getFileName(String path)      {          int separatorIndex = path.lastIndexOf("/");          return (separatorIndex < 0) ? path : path.substring(separatorIndex + 1, path.length());      }        /** * 加载图片 * * @param view * @param url * @throws IOException */      private void _displayImage(final ImageView view, final String url, final int errorResId)      {          final Request request = new Request.Builder()                  .url(url)                  .build();          Call call = mOkHttpClient.newCall(request);          call.enqueue(new Callback()          {              @Override              public void onFailure(Request request, IOException e)              {                  setErrorResId(view, errorResId);              }                @Override              public void onResponse(Response response)              {                  InputStream is = null;                  try                  {                      is = response.body().byteStream();                      ImageUtils.ImageSize actualImageSize = ImageUtils.getImageSize(is);                      ImageUtils.ImageSize imageViewSize = ImageUtils.getImageViewSize(view);                      int inSampleSize = ImageUtils.calculateInSampleSize(actualImageSize, imageViewSize);                      try                      {                          is.reset();                      } catch (IOException e)                      {                          response = _getAsyn(url);                          is = response.body().byteStream();                      }                        BitmapFactory.Options ops = new BitmapFactory.Options();                      ops.inJustDecodeBounds = false;                      ops.inSampleSize = inSampleSize;                      final Bitmap bm = BitmapFactory.decodeStream(is, null, ops);                      mDelivery.post(new Runnable()                      {                          @Override                          public void run()                          {                              view.setImageBitmap(bm);                          }                      });                  } catch (Exception e)                  {                      setErrorResId(view, errorResId);                    } finally                  {                      if (is != null) try                      {                          is.close();                      } catch (IOException e)                      {                          e.printStackTrace();                      }                  }              }          });          }        private void setErrorResId(final ImageView view, final int errorResId)      {          mDelivery.post(new Runnable()          {              @Override              public void run()              {                  view.setImageResource(errorResId);              }          });      }          //*************对外公布的方法************          public static Response getAsyn(String url) throws IOException      {          return getInstance()._getAsyn(url);      }          public static String getAsString(String url) throws IOException      {          return getInstance()._getAsString(url);      }        public static void getAsyn(String url, ResultCallback callback)      {          getInstance()._getAsyn(url, callback);      }        public static Response post(String url, Param... params) throws IOException      {          return getInstance()._post(url, params);      }        public static String postAsString(String url, Param... params) throws IOException      {          return getInstance()._postAsString(url, params);      }        public static void postAsyn(String url, final ResultCallback callback, Param... params)      {          getInstance()._postAsyn(url, callback, params);      }          public static void postAsyn(String url, final ResultCallback callback, Map<String, String> params)      {          getInstance()._postAsyn(url, callback, params);      }          public static Response post(String url, File[] files, String[] fileKeys, Param... params) throws IOException      {          return getInstance()._post(url, files, fileKeys, params);      }        public static Response post(String url, File file, String fileKey) throws IOException      {          return getInstance()._post(url, file, fileKey);      }        public static Response post(String url, File file, String fileKey, Param... params) throws IOException      {          return getInstance()._post(url, file, fileKey, params);      }        public static void postAsyn(String url, ResultCallback callback, File[] files, String[] fileKeys, Param... params) throws IOException      {          getInstance()._postAsyn(url, callback, files, fileKeys, params);      }          public static void postAsyn(String url, ResultCallback callback, File file, String fileKey) throws IOException      {          getInstance()._postAsyn(url, callback, file, fileKey);      }          public static void postAsyn(String url, ResultCallback callback, File file, String fileKey, Param... params) throws IOException      {          getInstance()._postAsyn(url, callback, file, fileKey, params);      }        public static void displayImage(final ImageView view, String url, int errorResId) throws IOException      {          getInstance()._displayImage(view, url, errorResId);      }          public static void displayImage(final ImageView view, String url)      {          getInstance()._displayImage(view, url, -1);      }        public static void downloadAsyn(String url, String destDir, ResultCallback callback)      {          getInstance()._downloadAsyn(url, destDir, callback);      }        //****************************          private Request buildMultipartFormRequest(String url, File[] files,                                                String[] fileKeys, Param[] params)      {          params = validateParam(params);            MultipartBuilder builder = new MultipartBuilder()                  .type(MultipartBuilder.FORM);            for (Param param : params)          {              builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + param.key + "\""),                      RequestBody.create(null, param.value));          }          if (files != null)          {              RequestBody fileBody = null;              for (int i = 0; i < files.length; i++)              {                  File file = files[i];                  String fileName = file.getName();                  fileBody = RequestBody.create(MediaType.parse(guessMimeType(fileName)), file);                  //TODO 根据文件名设置contentType                  builder.addPart(Headers.of("Content-Disposition",                                  "form-data; name=\"" + fileKeys[i] + "\"; filename=\"" + fileName + "\""),                          fileBody);              }          }            RequestBody requestBody = builder.build();          return new Request.Builder()                  .url(url)                  .post(requestBody)                  .build();      }        private String guessMimeType(String path)      {          FileNameMap fileNameMap = URLConnection.getFileNameMap();          String contentTypeFor = fileNameMap.getContentTypeFor(path);          if (contentTypeFor == null)          {              contentTypeFor = "application/octet-stream";          }          return contentTypeFor;      }          private Param[] validateParam(Param[] params)      {          if (params == null)              return new Param[0];          else return params;      }        private Param[] map2Params(Map<String, String> params)      {          if (params == null) return new Param[0];          int size = params.size();          Param[] res = new Param[size];          Set<Map.Entry<String, String>> entries = params.entrySet();          int i = 0;          for (Map.Entry<String, String> entry : entries)          {              res[i++] = new Param(entry.getKey(), entry.getValue());          }          return res;      }        private static final String SESSION_KEY = "Set-Cookie";      private static final String mSessionKey = "JSESSIONID";        private Map<String, String> mSessions = new HashMap<String, String>();        private void deliveryResult(final ResultCallback callback, Request request)      {          mOkHttpClient.newCall(request).enqueue(new Callback()          {              @Override              public void onFailure(final Request request, final IOException e)              {                  sendFailedStringCallback(request, e, callback);              }                @Override              public void onResponse(final Response response)              {                  try                  {                      final String string = response.body().string();                      if (callback.mType == String.class)                      {                          sendSuccessResultCallback(string, callback);                      } else                      {                          Object o = mGson.fromJson(string, callback.mType);                          sendSuccessResultCallback(o, callback);                      }                      } catch (IOException e)                  {                      sendFailedStringCallback(response.request(), e, callback);                  } catch (com.google.gson.JsonParseException e)//Json解析的错误                  {                      sendFailedStringCallback(response.request(), e, callback);                  }                }          });      }        private void sendFailedStringCallback(final Request request, final Exception e, final ResultCallback callback)      {          mDelivery.post(new Runnable()          {              @Override              public void run()              {                  if (callback != null)                      callback.onError(request, e);              }          });      }        private void sendSuccessResultCallback(final Object object, final ResultCallback callback)      {          mDelivery.post(new Runnable()          {              @Override              public void run()              {                  if (callback != null)                  {                      callback.onResponse(object);                  }              }          });      }        private Request buildPostRequest(String url, Param[] params)      {          if (params == null)          {              params = new Param[0];          }          FormEncodingBuilder builder = new FormEncodingBuilder();          for (Param param : params)          {              builder.add(param.key, param.value);          }          RequestBody requestBody = builder.build();          return new Request.Builder()                  .url(url)                  .post(requestBody)                  .build();      }          public static abstract class ResultCallback<T> {          Type mType;            public ResultCallback()          {              mType = getSuperclassTypeParameter(getClass());          }            static Type getSuperclassTypeParameter(Class<?> subclass)          {              Type superclass = subclass.getGenericSuperclass();              if (superclass instanceof Class)              {                  throw new RuntimeException("Missing type parameter.");              }              ParameterizedType parameterized = (ParameterizedType) superclass;              return $Gson$Types.canonicalize(parameterized.getActualTypeArguments()[0]);          }            public abstract void onError(Request request, Exception e);            public abstract void onResponse(T response);      }        public static class Param {          public Param()          {          }            public Param(String key, String value)          {              this.key = key;              this.value = value;          }            String key;          String value;      }      }

源码地址okhttp-utils，大家可以自己下载查看。

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参考文章

来自： http://blog.csdn.net//lmj623565791/article/details/47911083