本文实例为大家分享了java语言的Retrofit Rxjava实现下载文件的具体代码，供大家参考，具体内容如下，希望对大家学习java语言有所帮助。

本文采用 :retrofit + rxjava

1.引入：

//rxJava
compile 'io.reactivex:rxjava:latest.release'
compile 'io.reactivex:rxandroid:latest.release'
//network - squareup
compile 'com.squareup.retrofit2:retrofit:latest.release'
compile 'com.squareup.retrofit2:adapter-rxjava:latest.release'
compile 'com.squareup.okhttp3:okhttp:latest.release'
compile 'com.squareup.okhttp3:logging-interceptor:latest.release'

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2.增加下载进度监听：

public interface DownloadProgressListener {
void update(long bytesRead, long contentLength, boolean done);
}
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public class DownloadProgressResponseBody extends ResponseBody {
private ResponseBody responseBody;
private DownloadProgressListener progressListener;
private BufferedSource bufferedSource;
public DownloadProgressResponseBody(ResponseBody responseBody,
DownloadProgressListener progressListener) {
this.responseBody = responseBody;
this.progressListener = progressListener;
}
@Override
public MediaType contentType() {
return responseBody.contentType();
}
@Override
public long contentLength() {
return responseBody.contentLength();
}
@Override
public BufferedSource source() {
if (bufferedSource == null) {
bufferedSource = Okio.buffer(source(responseBody.source()));
}
return bufferedSource;
}
private Source source(Source source) {
return new ForwardingSource(source) {
long totalBytesRead = 0L;
@Override
public long read(Buffer sink, long byteCount) throws IOException {
long bytesRead = super.read(sink, byteCount);
// read() returns the number of bytes read, or -1 if this source is exhausted.
totalBytesRead += bytesRead != -1 ? bytesRead : 0;
if (null != progressListener) {
progressListener.update(totalBytesRead, responseBody.contentLength(), bytesRead == -1);
}
return bytesRead;
}
};
}
}
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public class DownloadProgressInterceptor implements Interceptor {
private DownloadProgressListener listener;
public DownloadProgressInterceptor(DownloadProgressListener listener) {
this.listener = listener;
}
@Override
public Response intercept(Chain chain) throws IOException {
Response originalResponse = chain.proceed(chain.request());
return originalResponse.newBuilder()
.body(new DownloadProgressResponseBody(originalResponse.body(), listener))
.build();
}
}
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3.创建下载进度的元素类：

public class Download implements Parcelable {
private int progress;
private long currentFileSize;
private long totalFileSize;
public int getProgress() {
return progress;
}
public void setProgress(int progress) {
this.progress = progress;
}
public long getCurrentFileSize() {
return currentFileSize;
}
public void setCurrentFileSize(long currentFileSize) {
this.currentFileSize = currentFileSize;
}
public long getTotalFileSize() {
return totalFileSize;
}
public void setTotalFileSize(long totalFileSize) {
this.totalFileSize = totalFileSize;
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(this.progress);
dest.writeLong(this.currentFileSize);
dest.writeLong(this.totalFileSize);
}
public Download() {
}
protected Download(Parcel in) {
this.progress = in.readInt();
this.currentFileSize = in.readLong();
this.totalFileSize = in.readLong();
}
public static final Parcelable.CreatorCREATOR = new Parcelable.Creator() {
@Override
public Download createFromParcel(Parcel source) {
return new Download(source);
}
@Override
public Download[] newArray(int size) {
return new Download[size];
}
};
}
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4.下载文件网络类：

public interface DownloadService {
@Streaming
@GET
Observabledownload(@Url String url);
}
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注：这里@Url是传入完整的的下载URL；不用截取

public class DownloadAPI {
private static final String TAG = "DownloadAPI";
private static final int DEFAULT_TIMEOUT = 15;
public Retrofit retrofit;
public DownloadAPI(String url, DownloadProgressListener listener) {
DownloadProgressInterceptor interceptor = new DownloadProgressInterceptor(listener);
OkHttpClient client = new OkHttpClient.Builder()
.addInterceptor(interceptor)
.retryOnConnectionFailure(true)
.connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.build();
retrofit = new Retrofit.Builder()
.baseUrl(url)
.client(client)
.addCallAdapterFactory(RxJavaCallAdapterFactory.create())
.build();
}
public void downloadAPK(@NonNull String url, final File file, Subscriber subscriber) {
Log.d(TAG, "downloadAPK: " + url);
retrofit.create(DownloadService.class)
.download(url)
.subscribeOn(Schedulers.io())
.unsubscribeOn(Schedulers.io())
.map(new Func1() {
@Override
public InputStream call(ResponseBody responseBody) {
return responseBody.byteStream();
}
})
.observeOn(Schedulers.computation())
.doOnNext(new Action1() {
@Override
public void call(InputStream inputStream) {
try {
FileUtils.writeFile(inputStream, file);
} catch (IOException e) {
e.printStackTrace();
throw new CustomizeException(e.getMessage(), e);
}
}
})
.observeOn(AndroidSchedulers.mainThread())
.subscribe(subscriber);
}
}

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然后就是调用了： 

该网络是在service里完成的

public class DownloadService extends IntentService {
private static final String TAG = "DownloadService";
private NotificationCompat.Builder notificationBuilder;
private NotificationManager notificationManager;
private String apkUrl = "//download.fir.im/v2/app/install/595c5959959d6901ca0004ac?download_token=1a9dfa8f248b6e45ea46bc5ed96a0a9e&source=update";
public DownloadService() {
super("DownloadService");
}
@Override
protected void onHandleIntent(Intent intent) {
notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationBuilder = new NotificationCompat.Builder(this)
.setSmallIcon(R.mipmap.ic_download)
.setContentTitle("Download")
.setContentText("Downloading File")
.setAutoCancel(true);
notificationManager.notify(0, notificationBuilder.build());
download();
}
private void download() {
DownloadProgressListener listener = new DownloadProgressListener() {
@Override
public void update(long bytesRead, long contentLength, boolean done) {
Download download = new Download();
download.setTotalFileSize(contentLength);
download.setCurrentFileSize(bytesRead);
int progress = (int) ((bytesRead * 100) / contentLength);
download.setProgress(progress);
sendNotification(download);
}
};
File outputFile = new File(Environment.getExternalStoragePublicDirectory
(Environment.DIRECTORY_DOWNLOADS), "file.apk");
String baseUrl = StringUtils.getHostName(apkUrl);
new DownloadAPI(baseUrl, listener).downloadAPK(apkUrl, outputFile, new Subscriber() {
@Override
public void onCompleted() {
downloadCompleted();
}
@Override
public void onError(Throwable e) {
e.printStackTrace();
downloadCompleted();
Log.e(TAG, "onError: " + e.getMessage());
}
@Override
public void onNext(Object o) {
}
});
}
private void downloadCompleted() {
Download download = new Download();
download.setProgress(100);
sendIntent(download);
notificationManager.cancel(0);
notificationBuilder.setProgress(0, 0, false);
notificationBuilder.setContentText("File Downloaded");
notificationManager.notify(0, notificationBuilder.build());
}
private void sendNotification(Download download) {
sendIntent(download);
notificationBuilder.setProgress(100, download.getProgress(), false);
notificationBuilder.setContentText(
StringUtils.getDataSize(download.getCurrentFileSize()) + "/" +
StringUtils.getDataSize(download.getTotalFileSize()));
notificationManager.notify(0, notificationBuilder.build());
}
private void sendIntent(Download download) {
Intent intent = new Intent(MainActivity.MESSAGE_PROGRESS);
intent.putExtra("download", download);
LocalBroadcastManager.getInstance(DownloadService.this).sendBroadcast(intent);
}
@Override
public void onTaskRemoved(Intent rootIntent) {
notificationManager.cancel(0);
}
}
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MainActivity代码：
public class MainActivity extends AppCompatActivity {
public static final String MESSAGE_PROGRESS = "message_progress";
private AppCompatButton btn_download;
private ProgressBar progress;
private TextView progress_text;
private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(MESSAGE_PROGRESS)) {
Download download = intent.getParcelableExtra("download");
progress.setProgress(download.getProgress());
if (download.getProgress() == 100) {
progress_text.setText("File Download Complete");
} else {
progress_text.setText(StringUtils.getDataSize(download.getCurrentFileSize())
+"/"+
StringUtils.getDataSize(download.getTotalFileSize()));
}
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn_download = (AppCompatButton) findViewById(R.id.btn_download);
progress = (ProgressBar) findViewById(R.id.progress);
progress_text = (TextView) findViewById(R.id.progress_text);
registerReceiver();
btn_download.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, DownloadService.class);
startService(intent);
}
});
}
private void registerReceiver() {
LocalBroadcastManager bManager = LocalBroadcastManager.getInstance(this);
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(MESSAGE_PROGRESS);
bManager.registerReceiver(broadcastReceiver, intentFilter);
}
}
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