0913Android基礎網絡技術之下載（AsyncTask）

下載

　　通過urlconnection以及線程實現下載
　　下載之前要添加權限，以及在主線程中註冊

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

　　註冊

        <activity android:name=".MyDownloadActivity"></activity>

單線程下載

　　通過繼承AsyncTask新開一個線程，將下載過程中的數據用來設置progressbar

 class MyAsynvTask extends AsyncTask<String,Integer,String>{
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            super.onProgressUpdate(values);
            int all=values[1];
            int current=values[0];
            int progress= (int) (current*100.0/all);
            mProgressBar.setProgress(progress);
        }

        @Override
        protected String doInBackground(String... params) {
            try {
                URL url=new URL("http://192.168.0.44:8080/MyServiceTest/music/aa.mp3");
                URLConnection connection=url.openConnection();
                int length=connection.getContentLength();
                InputStream is=connection.getInputStream();
                File file=new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC),"ee.mp3");
                if(!file.exists()){
                    file.createNewFile();
                }
                FileOutputStream os=new FileOutputStream(file);
                byte[] array=new byte[1024];
                int sum=0;
                int index=is.read(array);
                while (index!=-1){
                    os.write(array,0,index);
                    sum+=index;
                    publishProgress(sum,length);
                    index=is.read(array);
                }
                os.flush();
                os.close();
                is.close();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    }

　　啓動線程

new MyAsynvTask().execute();

多線程下載

　　新建線程類

package com.example.laowang.myinternet;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * Created by Administrator on 2015/9/13.
 */
public class MultiThread extends Thread {

    private int sum=0;
    private long start;
    private long end;
    private String urlPath;
    private String filePath;

    public MultiThread(long start, long end, String url, String filePath) {
        this.start = start;
        this.end = end;
        this.urlPath = url;
        this.filePath = filePath;
    }


    public int getSum() {
        return sum;
    }

    @Override
    public void run() {
        try {
            URL url=new URL(urlPath);
            URLConnection connection=url.openConnection();
//            如果爲true，則允許進行用戶交互（即下載前訪問是否下載）
            connection.setAllowUserInteraction(true);

            connection.setRequestProperty("Range", "bytes=" + start + "-"
                    + end);
            InputStream is= connection.getInputStream();
            byte [] array=new byte[1024];
//            is.read(array);
            File file=new File(filePath);
//            RandomAccessFile是用來訪問那些保存數據記錄的文件的，你就可以用seek( )方法來訪問記錄，並進行讀寫了。
//              這些記錄的大小不必相同；但是其大小和位置必須是可知的。但是該類僅限於操作文件。
            RandomAccessFile randomAccessFileile=new RandomAccessFile(file,"rw");
//            只有RandomAccessFile纔有seek搜尋方法，而這個方法也只適用於文件
            randomAccessFileile.seek(start);
            int index=is.read(array);
            while (index!=-1){
                randomAccessFileile.write(array,0,index);
                sum+=index;
                index=is.read(array);
            }
            randomAccessFileile.close();
            is.close();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

　　在活動中運行線程

  new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            String urlPath="http://192.168.0.44:8080/MyServiceTest/music/aa.mp3";
                            URL  url = new URL(urlPath);
                            URLConnection connection=url.openConnection();
//                            獲得文件的長度
                            length=connection.getContentLength();
//                            新建存放下載內容的文件。
                            File file=new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC),"dd.mp3");
                            if(!file.exists()){
                                file.createNewFile();
                            }


//                            新建多線程對象，打開五個線程同時進行下載。
                            MultiThread[] threads=new MultiThread[5];
                            for (int i=0;i<5;i++){
                                MultiThread thread=null;
//                                最後一部分，由於極大的可能沒有正處，所有這邊設置結束長度爲文件的長度。
                                if(i==4){
                                    thread = new MultiThread(length / 5*4, length , urlPath, file.getAbsolutePath());
                                }else {
//                                 傳入起始位置，結束位置，下載路徑，下載文件存放路徑。因爲包前包後所以減一
                                    thread = new MultiThread(length / 5 * i, length / 5 * (i + 1)-1, urlPath, file.getAbsolutePath());
                                }
                                thread.start();
                                threads[i]=thread;
                            }

//                          設置進度條
                            boolean isFinish=true;
                            while(isFinish){
                                int sum=0;
//                                獲得五個線程的實時長度的和
                                for (MultiThread thread:threads){
                                    sum+= thread.getSum();
                                }
                                Message msg=  handler.obtainMessage();
                                msg.what=0x23;
                                msg.arg1=sum;
                                handler.sendMessage(msg);
//
                                if(sum+10>=length){
                                    isFinish=false;
                                }
                                Thread.sleep(1000);
                            }

                        } catch (MalformedURLException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                    }
                }).start();

單線程以及多線程下載運行gif

　　達到的效果

全部代碼

　　活動
　　

package com.example.laowang.myinternet;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.ProgressBar;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * Created by Administrator on 2015/9/11.
 */
public class MyDownloadActivity extends Activity implements View.OnClickListener {
    private Button mBtnSingelDownload;
    private Button mBtnMulThreadDownload;
    private ProgressBar mProgressBar;
    int length;
    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case 0x23:
//                    將進度條最大值設爲文件最大值。
                    mProgressBar.setMax(length);
                    mProgressBar.setProgress(msg.arg1);
//                    mProgressBar.setProgress((int) (msg.arg1*100.0/length));
                    break;
            }
        }
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_download);

        mBtnSingelDownload = (Button) findViewById(R.id.button_signal_thread_download);
        mBtnMulThreadDownload = (Button) findViewById(R.id.button_mul_thread_download);
        mProgressBar= (ProgressBar) findViewById(R.id.progressBar);

        mBtnSingelDownload.setOnClickListener(this);
        mBtnMulThreadDownload.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.button_signal_thread_download:
                new MyAsynvTask().execute();
                break;
            case R.id.button_mul_thread_download:
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            String urlPath="http://192.168.0.44:8080/MyServiceTest/music/aa.mp3";
                            URL  url = new URL(urlPath);
                            URLConnection connection=url.openConnection();
//                            獲得文件的長度
                            length=connection.getContentLength();
//                            新建存放下載內容的文件。
                            File file=new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC),"dd.mp3");
                            if(!file.exists()){
                                file.createNewFile();
                            }


//                            新建多線程對象，打開五個線程同時進行下載。
                            MultiThread[] threads=new MultiThread[5];
                            for (int i=0;i<5;i++){
                                MultiThread thread=null;
//                                最後一部分，由於極大的可能沒有正處，所有這邊設置結束長度爲文件的長度。
                                if(i==4){
                                    thread = new MultiThread(length / 5*4, length , urlPath, file.getAbsolutePath());
                                }else {
//                                 傳入起始位置，結束位置，下載路徑，下載文件存放路徑。因爲包前包後所以減一
                                    thread = new MultiThread(length / 5 * i, length / 5 * (i + 1)-1, urlPath, file.getAbsolutePath());
                                }
                                thread.start();
                                threads[i]=thread;
                            }

//                          設置進度條
                            boolean isFinish=true;
                            while(isFinish){
                                int sum=0;
//                                獲得五個線程的實時長度的和
                                for (MultiThread thread:threads){
                                    sum+= thread.getSum();
                                }
                                Message msg=  handler.obtainMessage();
                                msg.what=0x23;
                                msg.arg1=sum;
                                handler.sendMessage(msg);
//
                                if(sum+10>=length){
                                    isFinish=false;
                                }
                                Thread.sleep(1000);
                            }

                        } catch (MalformedURLException e) {
                            e.printStackTrace();
                        } catch (IOException e) {
                            e.printStackTrace();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }

                    }
                }).start();
                break;
            default:
                break;
        }
    }

    class MyAsynvTask extends AsyncTask<String,Integer,String>{
        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
        }

        @Override
        protected void onProgressUpdate(Integer... values) {
            super.onProgressUpdate(values);
            int all=values[1];
            int current=values[0];
            int progress= (int) (current*100.0/all);
            mProgressBar.setProgress(progress);
        }

        @Override
        protected String doInBackground(String... params) {
            try {
                URL url=new URL("http://192.168.0.44:8080/MyServiceTest/music/aa.mp3");
                URLConnection connection=url.openConnection();
                int length=connection.getContentLength();
                InputStream is=connection.getInputStream();
                File file=new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_MUSIC),"ee.mp3");
                if(!file.exists()){
                    file.createNewFile();
                }
                FileOutputStream os=new FileOutputStream(file);
                byte[] array=new byte[1024];
                int sum=0;
                int index=is.read(array);
                while (index!=-1){
                    os.write(array,0,index);
                    sum+=index;
                    publishProgress(sum,length);
                    index=is.read(array);
                }
                os.flush();
                os.close();
                is.close();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    }
}

　　多線程下載新開的線程類

package com.example.laowang.myinternet;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

/**
 * Created by Administrator on 2015/9/13.
 */
public class MultiThread extends Thread {

    private int sum=0;
    private long start;
    private long end;
    private String urlPath;
    private String filePath;

    public MultiThread(long start, long end, String url, String filePath) {
        this.start = start;
        this.end = end;
        this.urlPath = url;
        this.filePath = filePath;
    }


    public int getSum() {
        return sum;
    }

    @Override
    public void run() {
        try {
            URL url=new URL(urlPath);
            URLConnection connection=url.openConnection();
//            如果爲true，則允許進行用戶交互（即下載前訪問是否下載）
            connection.setAllowUserInteraction(true);

            connection.setRequestProperty("Range", "bytes=" + start + "-"
                    + end);
            InputStream is= connection.getInputStream();
            byte [] array=new byte[1024];
//            is.read(array);
            File file=new File(filePath);
//            RandomAccessFile是用來訪問那些保存數據記錄的文件的，你就可以用seek( )方法來訪問記錄，並進行讀寫了。
//              這些記錄的大小不必相同；但是其大小和位置必須是可知的。但是該類僅限於操作文件。
            RandomAccessFile randomAccessFileile=new RandomAccessFile(file,"rw");
//            只有RandomAccessFile纔有seek搜尋方法，而這個方法也只適用於文件
            randomAccessFileile.seek(start);
            int index=is.read(array);
            while (index!=-1){
                randomAccessFileile.write(array,0,index);
                sum+=index;
                index=is.read(array);
            }
            randomAccessFileile.close();
            is.close();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

　　佈局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:gravity="center"
    android:orientation="vertical">

    <Button
        android:id="@+id/button_mul_thread_download"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="多線程下載" />
    <Button
        android:id="@+id/button_signal_thread_download"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="單線程下載" />

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_margin="5dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

0913Android基礎網絡技術之下載（AsyncTask）

下載

單線程下載

多線程下載

單線程以及多線程下載運行gif

全部代碼

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0913Android基礎網絡技術之下載（AsyncTask）

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