Http多线程下载文件

package unit; import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.math.BigDecimal;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Collections;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors; /**
* 文件下载
*/
public class HttpUtils {
static long sumContent = 0;
static float useTime = 0;
ArrayList<Float> speed = new ArrayList<Float>();
public static void main(String[] args) {
String url ="http://xcy1.xiaoshikd.com/python3.zip\r\n";
String dirPath = "D:/111/downLoad/";
String dirPath2 = "D:/222/downLoad/";
String dirPath3 = "D:/333/downLoad/";
HttpUtils.download(url, dirPath, "============");
HttpUtils.download(url, dirPath2, "============================");
HttpUtils.download(url, dirPath3, "==============================================");
} public static void download(String url, String filePath, final String message) {
HttpUtils.getInstance().download(url, filePath, new HttpClientDownLoadProgress() {
@Override
public void onProgress(int progress) {
System.out.println("download progress "+message+ progress+"%");
}
});
} /**
* 最大线程池
*/
public static final int THREAD_POOL_SIZE = 4; public interface HttpClientDownLoadProgress {
public void onProgress(int progress);
} private static HttpUtils httpClientDownload; private ExecutorService downloadExcutorService; private HttpUtils() {
downloadExcutorService = Executors.newFixedThreadPool(THREAD_POOL_SIZE);
} public static HttpUtils getInstance() {
if (httpClientDownload == null) {
httpClientDownload = new HttpUtils();
}
return httpClientDownload;
} /**
* 下载文件
*
* @param url
* @param filePath
* @param progress
* 进度回调
*/
public void download(final String url, final String filePath, final HttpClientDownLoadProgress progress) {
downloadExcutorService.execute(new Runnable() {
@Override
public void run() {
httpDownloadFile(url, filePath, progress);
}
});
} /**
* 下载文件
* @param url
* @param filePath
*/
private void httpDownloadFile(String strUrl, String filePath, HttpClientDownLoadProgress progress) {
try {
long startTime = System.currentTimeMillis();
URL url = new URL(strUrl);
String file = url.getFile();
String fileName = file.substring(file.lastIndexOf('/')+1);
URLConnection conn = url.openConnection();
InputStream is = conn.getInputStream();
long contentLength = conn.getContentLength();
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[65536];
int r = 0;
long totalRead = 0;
while ((r = is.read(buffer)) > 0) {
output.write(buffer, 0, r);
totalRead += r;
sumContent+=r;
if (progress != null) {// 回调进度
progress.onProgress((int) (totalRead * 100 / contentLength));
}
} /**
* 将下载文件写入本地
*/
File f = new File(filePath);
if(!f.exists()) {
f.mkdirs();
}
filePath = filePath+fileName;
FileOutputStream fos = new FileOutputStream(filePath);
output.writeTo(fos);
output.flush(); Long endTime = System.currentTimeMillis();
useTime = (float)(endTime-startTime)/1000;
getDoloadResult(sumContent, useTime); output.close();
fos.close();
is.close();
downloadExcutorService.shutdown();
} catch (Exception e) {
e.printStackTrace();
downloadExcutorService.shutdown();
}
} public void getDoloadResult(long contentLength, float useTime) {
System.out.println("sumContentLength： "+contentLength);
System.out.println("useTime： "+useTime); float bySpead = contentLength/useTime/1024/1024;
BigDecimal b = new BigDecimal(bySpead);
bySpead = b.setScale(2, 4).floatValue();;
speed.add(bySpead);
System.out.println("avgSpeed: "+bySpead+" M/s");
System.out.println("maxSpeed: "+Collections.max(speed)+" M/s");
}
}