多线程下载加载视频

 DialogUtlis

import android.content.DialogInterface;import android.content.Intent;import android.net.Uri;import android.os.AsyncTask;import android.os.SystemClock;import android.support.v7.app.AlertDialog;import com.example.samsung.zk.net.DownLoadThread;import java.io.File;import java.io.IOException;public class DialogUtils {    public static long MAX_SIZE = 0;    public static long PROGRESS = -2;    public static void showUpdataDialog(final Context context){        AlertDialog.Builder builder = new AlertDialog.Builder(context);        builder.setTitle("是否更新");        builder.setMessage("太旧了，更新吧");        builder.setNegativeButton("就不", null);        builder.setPositiveButton("可以", new DialogInterface.OnClickListener() {            @Override            public void onClick(DialogInterface dialogInterface, int i) {                new DownLoadThread("http://mirror.aarnet.edu.au/pub/TED-talks/911Mothers_2010W-480p.mp4", context.getCacheDir() + "911Mothers_2010W-480p.mp4").start();                showProgress(context);            }        });        builder.show();    }    public static void showProgress(final Context context){        final ProgressDialog pd = new ProgressDialog(context);        pd.setTitle("正在更新");        pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);        pd.setMax(100);        pd.show();        new AsyncTask<String, Integer, String>(){            @Override            protected String doInBackground(String... strings) {                while (PROGRESS+1 < MAX_SIZE){                    SystemClock.sleep(100);                    if(MAX_SIZE>0)                    {                        publishProgress((int)(PROGRESS * 100 / MAX_SIZE));                    }                }                return null;            }            @Override            protected void onPostExecute(String s) {                super.onPostExecute(s);                pd.dismiss();//                File file = new File(context.getCacheDir() + "/taobao_161.apk");//                String[] command = {"chmod", "777", file.getPath() };//                ProcessBuilder builder = new ProcessBuilder(command);//                try {//                    builder.start();//                } catch (IOException e) {//                    e.printStackTrace();//                }//////                Intent intent = new Intent(Intent.ACTION_VIEW);//// 由于没有在Activity环境下启动Activity,设置下面的标签//                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);//                intent.setDataAndType(Uri.fromFile(file)),//                        "application/vnd.android.package-archive"),//                context.startActivity(intent);                File file = new File(context.getCacheDir() + "/app-release.apk");                String command = "chmod " + "777" + " " + file.getPath();                Runtime runtime = Runtime.getRuntime();                try {                    runtime.exec(command);                } catch (IOException e) {                    e.printStackTrace();                }                Intent intent = new Intent(Intent.ACTION_VIEW);// 由于没有在Activity环境下启动Activity,设置下面的标签                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);                intent.setDataAndType(Uri.fromFile(file),                        "application/vnd.android.package-archive");context.startActivity(intent);            }            @Override            protected void onProgressUpdate(Integer... values) {                super.onProgressUpdate(values);                pd.setProgress(values[0]);            }        }.execute();    }}

             DowLoadTasK

package com.example.samsung.zk.net;/** * Created by jiajiajia on 2017/11/11. */public class DownLoadTask extends Thread{    String downLoadUrl;    String path;    int blockSize;    int startPosition;    public DownLoadTask(String downLoadUrl, String path, int blockSize, int startPosition) {        this.downLoadUrl = downLoadUrl;        this.path = path;        this.blockSize = blockSize;        this.startPosition = startPosition;    }    @Override    public void run() {        super.run();        NetUtils.downloadFile(downLoadUrl,path,blockSize,startPosition);    }}

       DownloadThread

package com.example.samsung.zk.net;import com.example.samsung.zk.utils.DialogUtils;/** * Created by jiajiajia on 2017/11/11. */public class DownLoadThread extends Thread{    private String downLoadUrl="";    private String path;    private int threadNum=5;    public DownLoadThread(String downLoadUrl, String path) {        this.downLoadUrl = downLoadUrl;        this.path = path;        this.threadNum = threadNum;    }    @Override    public void run() {        int len=NetUtils.getFileLength(downLoadUrl);        DialogUtils.MAX_SIZE=len;        int blockSize=len/threadNum;        for (int i = 0; i <threadNum ; i++) {            int startPosition=i*blockSize;            if(i==threadNum-1)            {                blockSize=len-blockSize*(threadNum-1);            }            new DownLoadTask(downLoadUrl,path,blockSize,startPosition).start();        }    }}

              NetUtlis

package com.example.samsung.zk.net;import android.util.Log;import com.example.samsung.zk.utils.DialogUtils;import java.io.BufferedInputStream;import java.io.File;import java.io.IOException;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.URL;public class NetUtils {    public static void downloadFile(String downloadUrl, String path, int blockSize, int startPosition){        BufferedInputStream bis = null;        RandomAccessFile raf = null;        try {            File f = new File(path);            if(!f.exists()){                f.createNewFile();            }            URL url = new URL(downloadUrl);            HttpURLConnection conn = (HttpURLConnection) url.openConnection();            conn.setReadTimeout(8000);            conn.setConnectTimeout(8000);//            long start = 0;            if(blockSize > 0){//                //使用线程id来计算 当前线程的开始位置和结束位置//                start = blockSize * threadId;                long end = blockSize + startPosition - 1;                //多线程下载  需要告诉服务器我要请求的是哪部分内容  需要写在请求头里面                conn.setRequestProperty("Range", "bytes=" + startPosition + "-" + end);                Log.i(Thread.currentThread() + "======", "bytes=" + startPosition + "-" + end);            }            int code = conn.getResponseCode();            if(code < 400){                bis = new BufferedInputStream(conn.getInputStream());                raf = new RandomAccessFile(f, "rwd");                //                raf.seek(startPosition);                //                int len = 0;                byte[] buff = new byte[1024 * 8];                while((len = bis.read(buff)) != -1){                    synchronized (NetUtils.class){                        raf.write(buff, 0, len);                        if(DialogUtils.PROGRESS<0)                        {                            DialogUtils.PROGRESS=0;                        }                        DialogUtils.PROGRESS += len;                    }                }            }        } catch (Exception e) {            e.printStackTrace();        }finally {            if(bis != null){                try {                    bis.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if(raf != null){                try {                    raf.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }    }    public static int getFileLength(String downloadUrl){        int len = 0;        try {            URL url = new URL(downloadUrl);            HttpURLConnection conn = (HttpURLConnection) url.openConnection();            conn.setReadTimeout(8000);            conn.setConnectTimeout(8000);            len = conn.getContentLength();        } catch (Exception e) {            e.printStackTrace();        }        return len;    }}

      MainActivity

package com.example.samsung.zk;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import com.example.samsung.zk.utils.DialogUtils;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        DialogUtils.showUpdataDialog(this);    }}