RxJava2.x+ReTrofit2.x多线程下载文件的示例代码

时间:2021-12-09 10:04:09

写在前面:

接到公司需求:要做一个apk升级的功能,原理其实很简单,百度也一大堆例子,可大部分都是用框架,要么就是HttpURLConnection,实在是不想这么干。正好看了两天的RxJava2.x+ReTrofit2.x,据说这俩框架是目前最火的异步请求框架了。固本文使用RxJava2.x+ReTrofit2.x实现多线程下载文件的功能。
如果对RxJava2.x+ReTrofit2.x不太了解的请先去看相关的文档。
大神至此请无视。

思路分析:

思路及其简洁明了,主要分为以下四步

1.获取服务器文件大小.
2.根据文件大小规划线程数量.
3.根据下载内容合并为完整文件.
4.调用安装,安装apk.
功能实现

来,接下来是你们最喜欢的撸代码环节

1.首先看引用

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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'

2.构造一个下载接口DownloadService.class

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public interface DownloadService {
  @Streaming
  @GET
  //downParam下载参数,传下载区间使用
  //url 下载链接
  Observable<ResponseBody> download(@Header("RANGE") String downParam,@Url String url);
}

3.为了使用方便封装了一个RetrofitHelper.class,主要用于:

a)实例化OkHttpClient和Retrofit.

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public RetrofitHelper(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();
}

b)封装下载方法,本次下载我使用的是三个下载线程,并没有动态分配,各位可以根据自己的需求去动态分配线程个数

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public Observable download(@NonNull final long start, @NonNull final long end, @NonNull final String url, final File file, final Subscriber subscriber) {
   String str = "";
   if (end == -1) {
     str = "";
   } else {
     str = end + "";
   }
   return retrofit.create(DownloadService.class).download("bytes=" + start + "-" + str, url).subscribeOn(Schedulers.io()).unsubscribeOn(Schedulers.io()).map(new Func1<ResponseBody, ResponseBody>() {
     @Override
     public ResponseBody call(ResponseBody responseBody) {
       return responseBody;
     }
   }).observeOn(Schedulers.computation()).doOnNext(new Action1<ResponseBody>() {
     @Override
     public void call(ResponseBody responseBody) {
       //第一次请求全部文件长度
       if (end == -1) {
         try {
           RandomAccessFile randomFile = new RandomAccessFile(file, "rw");
           randomFile.setLength(responseBody.contentLength());
           long one = responseBody.contentLength() / 3;
           download(0, one, url, file, subscriber).mergeWith(download(one, one * 2, url, file, subscriber)).mergeWith(download(one * 2, responseBody.contentLength(), url, file, subscriber)).subscribe(subscriber);
 
         } catch (IOException e) {
           e.printStackTrace();
         }
       } else {
         FileUtils fileUtils = new FileUtils();
         fileUtils.writeFile(start, end, responseBody.byteStream(), file);
       }
 
     }
   }).subscribeOn(AndroidSchedulers.mainThread());
 }

 4.调用下载

注:调用下载在MainAcitivity中进行,为了直观我们封装了进度拦截器以方便实现进度显示,但是本篇不在叙述进度拦截器的实现过程,如有需要可以留言。

a)实现监听对象

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subscriber = new Subscriber() {
      @Override
      public void onCompleted() {
        Log.e("MainActivity", "onCompleted下下载完成");
//        Toast.makeText(MainActivity.this, "onCompleted下下载完成", Toast.LENGTH_LONG).show();
        installAPK("mnt/sdcard/aaaaaaaaa.apk");
      }
 
      @Override
      public void onError(Throwable e) {
        e.printStackTrace();
        Log.e("MainActivity", "onError: " + e.getMessage());
      }
 
      @Override
      public void onNext(Object o) {
 
      }
    };

 b)调用封装的RetrofitHelper实现下载

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RetrofitHelper RetrofitHelper = new RetrofitHelper("http://gdown.baidu.com/data/wisegame/0904344dee4a2d92/", new DownloadProgressListener() {
     @Override
     public void update(long bytesRead, long contentLength, boolean done) {
 
       SharedPF.getSharder().setLong("update", bytesRead);
       pro.setProgress((int) ((double) bytesRead / contentLength * 100));
       temp++;
       if (temp <= 1) {
         Log.e("MainActivity", "update" + bytesRead + "");
       }
     }
   });
   RetrofitHelper.download(0, -1, "QQ_718.apk", new File("mnt/sdcard/", "aaaaaaaaa.apk"), subscriber).subscribe(new Subscriber() {
     @Override
     public void onCompleted() {
 
     }
 
     @Override
     public void onError(Throwable e) {
 
     }
 
     @Override
     public void onNext(Object o) {
 
     }
   });
 
 }

 注:最后贴一个apk安装的方法

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// 安装APK
public void installAPK(String filePath) {
  Intent intent = new Intent();
  intent.setAction("android.intent.action.VIEW");
  intent.addCategory("android.intent.category.DEFAULT");
  intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);// 广播里面操作需要加上这句,存在于一个独立的栈里
  intent.setDataAndType(Uri.fromFile(new File(filePath)), "application/vnd.android.package-archive");
  mainActivity.startActivity(intent);
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:http://blog.csdn.net/w525721508/article/details/77992988