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越来越发现一些第三方的框架比Android 原生大的API好用多了，而且android废弃掉了HttpClient,有必要学习一些访问网络的框架，于是踏上了一条框架学习之路，先前学习了Volley框架。今天来解析一下OkHttp框架。
一, OkHttp的简单使用，主要包括：
- 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
使用前，对于Android Studio的用户，可以选择添加:
<span style="font-family:SimSun;font-size:14px;color:#666666;">compile 'com.squareup.okhttp:okhttp:2.4.0'</span>注意:okhttp内部依赖okio，别忘了同时导入okio：
<span style="font-family:SimSun;font-size:14px;color:#666666;">gradle: compile 'com.squareup.okio:okio:1.5.0'</span>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。
<span style="font-family:SimSun;font-size:14px;color:#666666;">//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();
}
}); </span>-
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。 -
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。 -
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：
<span style="font-family:SimSun;font-size:14px;color:#666666;">@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);
}
});
}</span>- 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。
<span style="font-family:SimSun;font-size:14px;color:#666666;">Request request = buildMultipartFormRequest(
url, new File[]{file}, new String[]{fileKey}, null);
FormEncodingBuilder builder = new FormEncodingBuilder();
builder.add("username","张三");
Request request = new Request.Builder()
.url(url)
.post(builder.build())
.build();
mOkHttpClient.newCall(request).enqueue(new Callback(){});</span>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。
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
-
一般的get请求
<span style="font-family:SimSun;font-size:14px;color:#666666;">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
}
});</span>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。
<span style="font-family:SimSun;font-size:14px;color:#666666;">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")}
);</span>-
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.
-
文件下载
对于文件下载，提供url，目标dir，callback即可。
<span style="font-family:SimSun;font-size:14px;color:#666666;">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
}
});</span>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。
<span style="font-family:SimSun;font-size:14px;color:#666666;">OkHttpClientManager.displayImage(mImageView,
"http://images.csdn.net/20150817/1.jpg");</span>
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：
<span style="font-family:SimSun;font-size:14px;color:#666666;">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 + '\'' +
'}';
}
}</span><span style="font-family:SimSun;font-size:14px;color:#666666;">{"username":"zhy","password":"123"}</span><span style="font-family:SimSun;font-size:14px;color:#666666;">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
}
});</span> 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
<span style="font-family:SimSun;font-size:14px;color:#666666;">[{"username":"zhy","password":"123"},{"username":"lmj","password":"12345"}]</span>
<span style="font-family:SimSun;font-size:14px;color:#666666;">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());
}
});</span>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：
<span style="font-family:SimSun;font-size:14px;color:#666666;">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;
}
}</span>