Android网络连接----使用URLConnection实现从服务器上下载

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单线程下载

package com.test.shiweiwe.networkapp;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 com.test.shiweiwe.networkapp.mutildownloadthread.MultiDownload;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 DownLoadDemo extends Activity implements View.OnClickListener{    private Button mButtonSingle;    private ProgressBar mProgressBar;    private int length;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_download);        mProgressBar= (ProgressBar) findViewById(R.id.progressbar);        mButtonSingle= (Button) findViewById(R.id.single_download);        mButtonSingle.setOnClickListener(this);    }    @Override    public void onClick(View v) {        switch (v.getId()){            case R.id.single_download:                myDownload down= new myDownload();                down.execute();                break;        }    }class myDownload extends AsyncTask<String,Integer,String>{    @Override    protected void onProgressUpdate(Integer... values) {        super.onProgressUpdate(values);        mProgressBar.setProgress((int) (values[0]/values[1]*100.0));    }    @Override    protected void onPostExecute(String s) {        super.onPostExecute(s);    }    @Override    protected String doInBackground(String... params) {        try {            URL url = new URL("http://192.168.0.30:8080/MyWebTest/music/aa.mp3");            URLConnection connection = url.openConnection();            int length = connection.getContentLength();            InputStream inputStream = connection.getInputStream();            File file = new File(Environment.getExternalStorageDirectory(),"aa.mp3");            if(!file.exists()){                file.createNewFile();            }            FileOutputStream outputStream = new FileOutputStream(file);            byte[] bytes = new byte[1024];            int sum = 0;            int index = inputStream.read(bytes);            while(index!=-1){                outputStream.write(bytes,0,index);                sum+=index;                publishProgress(sum,length);                index=inputStream.read(bytes);            }            outputStream.flush();            outputStream.close();            inputStream.close();        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }        return null;    }}}

多线程下载

package com.test.shiweiwe.networkapp.mutildownloadthread;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 MultiDownload extends Thread{    private int sum=0;    private long start;    private long end;    private String urlPath;    private String filePath;    public MultiDownload(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();            connection.setAllowUserInteraction(true);//允许用户交互            connection.setRequestProperty("Range", "bytes=" + start + "-"                    + end);//            InputStream is= connection.getInputStream();            byte [] array=new byte[1024];//            is.read(array);            File file=new File(filePath);            RandomAccessFile randomAccessFileile=new RandomAccessFile(file,"rw");//允许随机读写            randomAccessFileile.seek(start);//找到文件的头            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();        }    }}

package com.test.shiweiwe.networkapp;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 com.test.shiweiwe.networkapp.mutildownloadthread.MultiDownload;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 DownLoadDemo extends Activity implements View.OnClickListener {    private Button mButtonSingle;    private Button mButtonMul;    private ProgressBar mProgressBar;    private int length;    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            switch (msg.what) {                case 0x23:                    mProgressBar.setProgress(msg.arg1 * 100 / length);                    break;            }        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_download);        mProgressBar = (ProgressBar) findViewById(R.id.progressbar);        mButtonMul = (Button) findViewById(R.id.mul_download);        mButtonMul.setOnClickListener(this);    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.mul_download:                new Thread(new Runnable() {                    @Override                    public void run() {                        try {//                            String urlPath="http://192.168.0.30:8080/MyWebTest/music/aa.mp3";                            String urlPath = "http://192.168.0.55:8088/WebTest/hello.jpg";                            URL url = new URL(urlPath);                            URLConnection connection = url.openConnection();                            length = connection.getContentLength();                            File file = new File(Environment.getExternalStorageDirectory(), "dd.jpg");                            if (!file.exists()) {                                file.createNewFile();                            }                            MultiDownload[] threads = new MultiDownload[5];                            for (int i = 0; i < 5; i++) {//包前包后                                MultiDownload thread = null;                                if (i == 4) {                                    thread = new MultiDownload(length / 5 * 4, length, urlPath, file.getAbsolutePath());                                } else {                                    thread = new MultiDownload(length / 5 * i, length / 5 * (i + 1) - 1, urlPath, file.getAbsolutePath());                                }                                thread.start();                                threads[i] = thread;                            }                            boolean isFinish = true;                            while (isFinish) {                                int sum = 0;                                for (MultiDownload 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;        }    }}

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