[转] Android OkHttp完全解析 是时候来了解OkHttp了

时间:2021-06-28 21:14:47

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'
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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:headermethod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()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
    }
    })
  2. 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。

  3. 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")}
    );
  4. 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.

  5. 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
    }
    });
  6. 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");
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    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"}
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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"}]
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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;
} }