使用HttpURLConnection（实现单线程多线程下载）
2015-09-12 08:57
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HttpURLConnection继承URLConnection因此也可向指定网站发送POST，GET请求
【2】获取指定URL对象指向的资源的大小,getContentLength()方法实现；
【3】在本地磁盘创建与资源大小相当的文件
【4】计算每个线程应该下载资源的分配（从那个字节开始，到哪个字节结束）
【5】依次创建启动多个线程下载
单线程下载
class SingleDownloadTask extends AsyncTask<String, Integer, String> {
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
// int count= Integer.parseInt(values[1]*100.0/values[0]);
mProgressBar.setProgress((int) (values[0] * 100.0 / values[1]));
}
@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();
//publishProgress(length);
InputStream is = connection.getInputStream();
File file = new File(Environment.getExternalStorageDirectory(), "aa.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;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
}多线程下载步骤
【1】创建URL对象【2】获取指定URL对象指向的资源的大小,getContentLength()方法实现；
【3】在本地磁盘创建与资源大小相当的文件
【4】计算每个线程应该下载资源的分配（从那个字节开始，到哪个字节结束）
【5】依次创建启动多个线程下载
private void MultiThreadDownload() {
new Thread() {
@Override
public void run() {
String urlPath = "http://192.168.0.30:8080/MyWebTest/music/aa.mp3";
try {
URL url = new URL(urlPath);
URLConnection connection = url.openConnection();
length = connection.getContentLength();
File file = new File(Environment.getExternalStorageDirectory(), "cc.mp3");
if (!file.exists()) {
file.createNewFile();
}
MultiThread[] threads = new MultiThread[5];
for (int i = 0; i < 5; i++) {
MultiThread thread = null;
if (i == 4) {
thread = new MultiThread(length / 5 * 4, length, urlPath, file.getAbsolutePath());
} else {
thread = new MultiThread(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 (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();
}public class MultiThread extends Thread{
public MultiThread(long start, long end, String url, String filePath) {
this.start = start;
this.end = end;
this.urlPath = url;
this.filePath = filePath;
}
private int sum=0;
private long start;
private long end;
private String urlPath;
private String filePath;
public int getSum() {
return sum;
}
@Override
public void run() {
try {
URL url = new URL(urlPath);
URLConnection connection=url.openConnection();
connection.setAllowUserInteraction(true);
connection.setRequestProperty("Range","byte="+start+"-"+end);
InputStream is=connection.getInputStream();
byte[] array=new byte[1024];
is.read(array);
File file=new File(filePath);
RandomAccessFile randomAccessFile=new RandomAccessFile(file,"rw");
randomAccessFile.seek(start);
int index=is.read(array);
while(index!=-1){
randomAccessFile.write(array,0,index);
sum+=index;
index=is.read(array);
}
randomAccessFile.close();
is.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}public class DownloadActivity extends Activity implements View.OnClickListener {
private Button mButtonSingle;
private Button mButtonMilti;
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;
default:
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_download);
mButtonSingle = (Button) findViewById(R.id.button_download_single);
mButtonMilti = (Button) findViewById(R.id.button_download_milti);
mProgressBar = (ProgressBar) findViewById(R.id.progressbar);
mButtonMilti.setOnClickListener(this);
mButtonSingle.setOnClickListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button_download_single:
SingleDownloadTask task = new SingleDownloadTask();
task.execute();
break;
case R.id.button_download_milti:
MultiThreadDownload();
break;
default:
break;
}
}
private void MultiThreadDownload() {
new Thread() {
@Override
public void run() {
String urlPath = "http://192.168.0.30:8080/MyWebTest/music/aa.mp3";
try {
URL url = new URL(urlPath);
URLConnection connection = url.openConnection();
length = connection.getContentLength();
File file = new File(Environment.getExternalStorageDirectory(), "cc.mp3");
if (!file.exists()) {
file.createNewFile();
}
MultiThread[] threads = new MultiThread[5];
for (int i = 0; i < 5; i++) {
MultiThread thread = null;
if (i == 4) {
thread = new MultiThread(length / 5 * 4, length, urlPath, file.getAbsolutePath());
} else {
thread = new MultiThread(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 (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();
}
class SingleDownloadTask extends AsyncTask<String, Integer, String> {
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
// int count= Integer.parseInt(values[1]*100.0/values[0]);
mProgressBar.setProgress((int) (values[0] * 100.0 / values[1]));
}
@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();
//publishProgress(length);
InputStream is = connection.getInputStream();
File file = new File(Environment.getExternalStorageDirectory(), "aa.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;
}
@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
}
}
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