Retrofit下载

最新推荐文章于 2023-12-07 10:51:32 发布

原创最新推荐文章于 2023-12-07 10:51:32 发布 · 342 阅读

0 ·

CC 4.0 BY-SA版权

本文介绍了一种使用Retrofit实现多线程文件下载的方法。通过定义接口获取文件总长度及各线程负责的数据范围，并利用OkHttp进行网络请求配置。通过创建线程类分配下载任务，并实时更新下载进度。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

一：Retrofit的接口

public interface ReqestApi {
//获得每个线程长度
    @Streaming
    @GET("{fileName}")
    Observable<ResponseBody> downloadFile(@Path("fileName") String fileName, @Header("Range") String range);
    //获得文件总长
    @Streaming
    @GET("{fileName}")
    Observable<ResponseBody> getFilelength(@Path("fileName") String fileName);
}

二：Retrofit的封装

public class RetrofitUtils {

    public static ReqestApi download(String basaUrl){
        OkHttpClient client=new OkHttpClient.Builder()
                .connectTimeout(5, TimeUnit.SECONDS)
                .readTimeout(5, TimeUnit.SECONDS)
                .build();
        //Retrofit的配置
        Retrofit retrofit=new Retrofit.Builder()
                .client(client)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .baseUrl(basaUrl)
                .build();
        ReqestApi reqestApi = retrofit.create(ReqestApi.class);
        return reqestApi;
    }


}

三：线程类

public class DownloadThread extends Thread{
    private String downloadUrl="";
    private String path;
    private int threadNum=5;
    long length;
    public static final String Url = "http://gdown.baidu.com/data/wisegame/d2fbbc8e64990454/";

    public DownloadThread(String downloadUrl, String path) {
        this.downloadUrl = downloadUrl;
        this.path = path;
    }
    public void show(){
//获得文件的总长  RetrofitUtils.download(Url).getFilelength(downloadUrl).observeOn(Schedulers.io()).subscribeOn(Schedulers.io()).subscribe(new Observer<ResponseBody>() {
            @Override
            public void onCompleted() {

            }

            @Override
            public void onError(Throwable throwable) {
                Log.i("-----onError-------", "onError: "+throwable.getMessage());
            }

            @Override
            public void onNext(ResponseBody responseBody) {
                length=responseBody.contentLength();
                downoadTask(length);
            }
        });
    }

//下载的任务，闯入总长用来分配
    public void downoadTask(Long length){
    //创建下载文件
        final File file=new File(path);
        if(!file.exists()){
            try {
                file.createNewFile();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        DialogUtils.MAX_SIZE=length;
        Log.i("------length-------", "downoadTask: "+length);
        long blockSize=length/threadNum;
        for (int i = 0; i < threadNum; i++) {
            final long startposition=blockSize*i;
            if(i==threadNum-1){
                blockSize=length-blockSize*(threadNum-1);
            }
            String range="bytes="+startposition+"-"+(startposition+blockSize-1);
            Log.i("------range-------", "downoadTask: "+range);
            RetrofitUtils.download(Url).downloadFile(downloadUrl,range).subscribeOn(Schedulers.io()).observeOn(Schedulers.io()).subscribe(new Observer<ResponseBody>() {
                @Override
                public void onCompleted() {

                }

                @Override
                public void onError(Throwable throwable) {
                    Log.i("-----error-----", "onResponse: "+throwable.getMessage());
                }

                @Override
                public void onNext(ResponseBody responseBody) {
                    try {
                        Log.i("-----error-----", "onResponse: "+"进来了");
                        BufferedInputStream bis=new BufferedInputStream(responseBody.byteStream());
                        RandomAccessFile raf=new RandomAccessFile(file,"rwd");
                        raf.seek(startposition);
                        byte[] buff=new byte[1024*8];
                        int len=0;
                        //读写操作
                        while ((len=bis.read(buff))!=-1){
                            raf.write(buff,0,len);
                            if(DialogUtils.PROGRESS<0){
                                DialogUtils.PROGRESS=0;
                            }
                            DialogUtils.PROGRESS+=len;
                            Log.i(Thread.currentThread() + "-----len-----", "onResponse: "+ startposition + len);
                        }

                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            });
        }

    }
}

五：dialog类

class DialogUtils {
    public static long MAX_SIZE=0;
    public static long PROGRESS=-2;
    public static void showUpdateDialog(final Context context){
        new AlertDialog.Builder(context)
                .setTitle("更新吧，二逼")
                .setNegativeButton("就不",null)
                .setPositiveButton("好吧，你赢了", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        //// TODO: 2017/11/22  
                        DownloadThread downloadThread=new DownloadThread("wangyiyunyinle_87.apk",context.getCacheDir()+"/hahah.apk");
                        downloadThread.show();
                        showProgress(context);
                    }
                })
                .show();
    }
    public static void showProgress(Context context){
        final ProgressDialog pd=new ProgressDialog(context);
        pd.setTitle("正在下载");
        pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
        pd.setMax(100);
        pd.show();
        new AsyncTask<String,Integer,String>(){

            @Override
            protected String doInBackground(String... params) {
                while (PROGRESS+1<MAX_SIZE){
                    SystemClock.sleep(10);
                    if(MAX_SIZE>0){
                        publishProgress((int)(PROGRESS*100/MAX_SIZE));
                    }
                }
                return null;
            }

            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                pd.dismiss();
            }

            @Override
            protected void onProgressUpdate(Integer... values) {
                super.onProgressUpdate(values);
                pd.setProgress(values[0]);
            }
        }.execute();
    }
}

mainactivity调用dialogutil