多线程下载httpurlConnection

MainActivity中的代码
package com.weektwopractise;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.weektwopractise.MoreXCDownload.DialogUtils;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

DialogUtils.ShowUpdateProgress(this);

}
}

进度框的工具类代码

package com.weektwopractise.MoreXCDownload;

import android.annotation.SuppressLint;
import android.app.ProgressDialog;
import android.content.Context;
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 android.util.Log;

import java.io.File;
import java.io.IOException;

/**
* User: Moyuchen
* Date: 2017-11-11 09:23
* Description：
*/
public class DialogUtils {
public static int MAX=0;
public static int PROGRESS=-2;
public static void ShowUpdateProgress(final Context context){
AlertDialog builder=new AlertDialog.Builder(context)
.setTitle("版本有点低，请选择更新最新版本")
.setPositiveButton("更新", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {

new DownloadThread("http://169.254.35.159:8080/wyq/jinritoutiao_460.apk",context.getCacheDir()+"/d.apk",4).start();
showDownProgress(context,context.getCacheDir()+"/d.apk");
}
})
.setNegativeButton("不用了",null)
.show();

}

private static void showDownProgress(final Context context, final String fileurl) {

final ProgressDialog dialog=new ProgressDialog(context);
dialog.setTitle("正在更新");
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setMax(100);
dialog.show();
new AsyncTask<String, Integer, String>() {
@SuppressLint("LongLogTag")
@Override
protected String doInBackground(String... strings) {
Log.i("==========DialogUtils========", "doInBackground:+Progress: "+PROGRESS+"Max:"+MAX);
while (PROGRESS<MAX) {
Log.i("==========DialogUtils========", "doInBackground:+Progress: "+PROGRESS+"Max:"+MAX);
SystemClock.sleep(100);
if (MAX > 0) {

publishProgress((int) (PROGRESS * 100 / MAX));
} else {
publishProgress(0);
}

}
return null;
}

@Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
dialog.dismiss();
File file=new File(fileurl);
//重新给下载的文件设置权限
String[] command = {"chmod", "777", file.getPath() };
ProcessBuilder builder = new ProcessBuilder(command);
try {
builder.start();
} catch (IOException e) {
e.printStackTrace();
}
//设置跳转到系统安装页面
Intent intent = new Intent(Intent.ACTION_VIEW);

intent.addCategory(Intent.CATEGORY_DEFAULT);

intent.setDataAndType(Uri.parse("file://"+fileurl),"application/vnd.android.package-archive");
context.startActivity(intent);
}

@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
dialog.setProgress(values[0]);
}
}.execute();
}
}

package com.weektwopractise.MoreXCDownload;

import android.annotation.SuppressLint;
import android.util.Log;

/**
* User: Moyuchen
* Date: 2017-11-11 08:42
* Description：
*/
public class DownloadThread extends Thread{
private String downUrl="";
private int ThreadNum=5;
private String
c2e0
path;

public DownloadThread(String downUrl,String path,int threadNum){
this.downUrl=downUrl;
this.path=path;
this.ThreadNum=threadNum;
}
@SuppressLint("LongLogTag")
@Override
public void run() {
super.run();

//获取要下载文件的长度，即大小
int fileLength = NetUtils.getFileContentLength(downUrl);
DialogUtils.MAX=fileLength;
Log.i("=============DownLoadThread===============", "fileLength: "+fileLength);
int DownSize=fileLength/ThreadNum;
for (int i=0;i<ThreadNum;i++){
int startPosition=i*DownSize;
if (i==ThreadNum-1) {
DownSize=fileLength-DownSize*(ThreadNum-1);
}
new DownTask(DownSize,downUrl,startPosition,path).start();
}

}
}

package com.weektwopractise.MoreXCDownload;

/**
* User: Moyuchen
* Date: 2017-11-11 09:00
* Description：
*/
public class DownTask extends Thread {
private int DownSize;
private String DownUrl;
private int startPosition;
private String path;

public DownTask(int downSize, String downUrl, int startPosition, String path) {
DownSize = downSize;
DownUrl = downUrl;
this.startPosition = startPosition;
this.path = path;
}

@Override
public void run() {
super.run();
NetUtils.DownLoad(DownUrl,DownSize,path,startPosition);
}
}

package com.weektwopractise.MoreXCDownload;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;

/**
* User: Moyuchen
* Date: 2017-11-11 08:49
* Description：
*/
public class NetUtils {

/**
* 获取要下的文件的长度
* @param downloadUrl
* @return
*/
public static int getFileContentLength(String downloadUrl){
int contentLength=0;
try {
URL url=new URL(downloadUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setConnectTimeout(5000);
con.setConnectTimeout(5000);
//获取下载的长度
contentLength = con.getContentLength();
} catch (Exception e) {
e.printStackTrace();
}
return  contentLength;
}
public static void DownLoad(String downUrl,int DownSize,String path,int startPosition){
BufferedInputStream buffer = null;
RandomAccessFile raf = null;
try {
File file=new File(path);
if (!file.exists()) {
file.createNewFile();
}
URL url=new URL(downUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setConnectTimeout(5000);
con.setReadTimeout(5000);

if (DownSize>0) {
int endPosition=DownSize+startPosition-1;
con.setRequestProperty("Range","bytes="+startPosition+"-"+endPosition);
}
int responseCode = con.getResponseCode();//获取响应码
if (400>responseCode) {
buffer = new BufferedInputStream(con.getInputStream());
raf = new RandomAccessFile(file, "rwd");
raf.seek(startPosition);
int len=0;
byte[] bytes=new byte[1024*8];
while ((len=buffer.read(bytes))!=-1){
synchronized (NetUtils.class){
raf.write(bytes,0,len);
if (DialogUtils.PROGRESS<0) {
DialogUtils.PROGRESS=0;
}
DialogUtils.PROGRESS+=len;
}
}
}

} catch (Exception e) {
e.printStackTrace();
}finally {
if (buffer!=null) {
try {
buffer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (raf!=null) {
try {
raf.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

}
}

<uses-permission android:name="android.permission.INTERNET"/>//网络权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>//SD卡读写权限
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>