public class RetrofitClient {

private static RetrofitClient mInstance;

private static Retrofit retrofit;

private RetrofitClient() {

retrofit = RetrofitBuilder.buildRetrofit();

}

/**

• 获取RetrofitClient实例.

• @return 返回RetrofitClient单例

*/

public static synchronized RetrofitClient getInstance() {

if (mInstance == null) {

mInstance = new RetrofitClient();

}

return mInstance;

}

private T create(Class clz) {

return retrofit.create(clz);

}

/**

• 单上传文件的封装.

• @param url 完整的接口地址

• @param file 需要上传的文件

• @param fileUploadObserver 上传回调

*/

public void upLoadFile(String url, File file,

FileUploadObserver fileUploadObserver) {

UploadFileRequestBody uploadFileRequestBody =

new UploadFileRequestBody(file, fileUploadObserver);

create(UploadFileApi.class)

.uploadFile(url, MultipartBuilder.fileToMultipartBody(file,

uploadFileRequestBody))

.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())

.subscribe(fileUploadObserver);

}

/**

• 多文件上传.

• @param url 上传接口地址

• @param files 文件列表

• @param fileUploadObserver 文件上传回调

*/

public void upLoadFiles(String url, List files,

FileUploadObserver fileUploadObserver) {

create(UploadFileApi.class)

.uploadFile(url, MultipartBuilder.filesToMultipartBody(files,

fileUploadObserver))

.subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())

.subscribe(fileUploadObserver);

}

}

这个是Retrofit客户端类，获取它的单例然后去调用它的上传文件的方法，可以看到我这里封装了两个方法，uploadFile是上传单个文件，uploadFiles方法上传多个文件.

因为我们需要构造一个Retrofit对象，所以这里有一个RetrofitBuilder类：

/**

• Retrofit构造器.

• @author devilwwj

• @since 2017/7/13

*/

public class RetrofitBuilder {

private static Retrofit retrofit;

public static synchronized Retrofit buildRetrofit() {

if (retrofit == null) {

Gson gson = new GsonBuilder().setDateFormat(“yyyy-MM-dd HH:mm:ss”).create();

GsonConverterFactory gsonConverterFactory = GsonConverterFactory.create(gson);

retrofit = new Retrofit.Builder().client(OkHttpManager.getInstance())

.baseUrl(AppConfig.HTTP_SERVER)

.addConverterFactory(gsonConverterFactory)

.addCallAdapterFactory(RxJava2CallAdapterFactory.create())

.build();

}

return retrofit;

}

}

可以看到，想构造Retrofit对象是需要获取OkhttpClient实例的。

定义上传文件接口

---

/**

• 上传API.

• @author devilwwj

• @since 2017/7/12

*/

public interface UploadFileApi {

String UPLOAD_FILE_URL = AppConfig.HTTP_SERVER + “file/upload”;

@POST

Observable uploadFile(@Url String url, @Body MultipartBody body);

}

这里就是Retrofit定义接口的形式，通过注解来表示各个参数，@POST表示发起post请求，@Url表示这是个请求地址，@Body表示这是请求体，关于Retrofit的各种注解的使用这里不多说，大家可以自行了解。

构造MultipartBody

---

上一步定义好了上传的接口，我们最终是要去构造MultipartBody，这一块就需要跟后台同学进行沟通了，根据接口定义来实现，这里是我们的实现：

/**

• MultipartBuilder.

• @author devilwwj

• @since 2017/7/13

*/

public class MultipartBuilder {

/**

• 单文件上传构造.

《Android学习笔记总结+最新移动架构视频+大厂安卓面试真题+项目实战源码讲义》

【docs.qq.com/doc/DSkNLaERkbnFoS0ZF】 完整内容开源分享

@param file 文件

• @param requestBody 请求体

• @return MultipartBody

*/

public static MultipartBody fileToMultipartBody(File file, RequestBody requestBody) {

MultipartBody.Builder builder = new MultipartBody.Builder();

JsonObject jsonObject = new JsonObject();

jsonObject.addProperty(“fileName”, file.getName());

jsonObject.addProperty(“fileSha”, Utils.getFileSha1(file));

jsonObject.addProperty(“appId”, “test0002”);

builder.addFormDataPart(“file”, file.getName(), requestBody);

builder.addFormDataPart(“params”, jsonObject.toString());

builder.setType(MultipartBody.FORM);

return builder.build();

}

/**

• 多文件上传构造.

• @param files 文件列表

• @param fileUploadObserver 文件上传回调

• @return MultipartBody

*/

public static MultipartBody filesToMultipartBody(List files,

FileUploadObserver fileUploadObserver) {

MultipartBody.Builder builder = new MultipartBody.Builder();

JsonArray jsonArray = new JsonArray();

Gson gson = new Gson();

for (File file : files) {

UploadFileRequestBody uploadFileRequestBody =

new UploadFileRequestBody(file, fileUploadObserver);

JsonObject jsonObject = new JsonObject();

jsonObject.addProperty(“fileName”, file.getName());

jsonObject.addProperty(“fileSha”, Utils.getFileSha1(file));

jsonObject.addProperty(“appId”, “test0002”);

jsonArray.add(jsonObject);

LogUtil.d(jsonObject.toString());

builder.addFormDataPart(“file”, file.getName(), uploadFileRequestBody);

}

builder.addFormDataPart(“params”, gson.toJson(jsonArray));

LogUtil.d(gson.toJson(jsonArray));

builder.setType(MultipartBody.FORM);

return builder.build();

}

}

自定义RequestBody

---

构造MultipartBody是需要去创建每个文件对应的ReqeustBody，但我们这边需要监听到文件上传成功、失败和进度的状态，所以需要去自定义：

/**

• 上传文件请求body.

• @author devilwwj

• @since 2017/7/12

*/

public class UploadFileRequestBody extends RequestBody {

private RequestBody mRequestBody;

private FileUploadObserver fileUploadObserver;

public UploadFileRequestBody(File file, FileUploadObserver fileUploadObserver) {

this.mRequestBody = RequestBody.create(MediaType.parse(“application/octet-stream”), file);

this.fileUploadObserver = fileUploadObserver;

}

@Override

public MediaType contentType() {

return mRequestBody.contentType();

}

@Override

public long contentLength() throws IOException {

return mRequestBody.contentLength();

}

@Override

public void writeTo(BufferedSink sink) throws IOException {

CountingSink countingSink = new CountingSink(sink);

BufferedSink bufferedSink = Okio.buffer(countingSink);

// 写入

mRequestBody.writeTo(bufferedSink);

// 刷新

// 必须调用flush，否则最后一部分数据可能不会被写入

bufferedSink.flush();

}

/**

• CountingSink.

*/

protected final class CountingSink extends ForwardingSink {

private long bytesWritten = 0;

public CountingSink(Sink delegate) {

super(delegate);

}

@Override

public void write(Buffer source, long byteCount) throws IOException {

super.write(source, byteCount);

bytesWritten += byteCount;

if (fileUploadObserver != null) {

fileUploadObserver.onProgressChange(bytesWritten, contentLength());

}

}

}

}

这里有个RxJava2的Observer的抽象类，主要是用来收到Rxjava2的事件：

/**

• 上传文件的RxJava2回调.

• @author devilwwj

• @since 2017/7/12

• @param 模板类

*/

public abstract class FileUploadObserver extends DefaultObserver {

@Override

public void onNext(T t) {

onUploadSuccess(t);

}

@Override

public void onError(Throwable e) {

onUploadFail(e);

}

@Override

public void onComplete() {

}

// 上传成功的回调

public abstract void onUploadSuccess(T t);

// 上传失败回调

public abstract void onUploadFail(Throwable e);

// 上传进度回调

public abstract void onProgress(int progress);

// 监听进度的改变

public void onProgressChange(long bytesWritten, long contentLength) {

onProgress((int) (bytesWritten * 100 / contentLength));

}

}

ok，到现在完整的代码实现已经说完。

具体使用方法

---

RetrofitClient.getInstance().upLoadFiles(UploadFileApi.UPLOAD_FILE_URL, files,

new FileUploadObserver() {

@Override

public void onUploadSuccess(ResponseBody responseBody) {

if (responseBody == null) {

LogUtil.e(“responseBody null”);

return;

}

try {

JSONObject jsonObject = new JSONObject(responseBody.string());

ArrayList fileIds = new ArrayList();

fileIds.add(jsonObject.getString(“fileId”));

} catch (IOException e) {

e.printStackTrace();

} catch (JSONException e) {

e.printStackTrace();

}

}