Linux Crontab 定时任务 命令详解

package com.mutildownloader;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.tenone.androidtest.R;

public class MainActivity extends Activity {
protected static final int DOWN_LOAD_ERROR = 0;
public static final int DOWN_LOAD_FINISH = 1;
protected static final int SERVICE_ERROR = 2;
public static final int UPDATE_TEXT = 3;
public static int threadCount = 3;
public static int runningThread = 3;
private EditText et_path;
private ProgressBar pb;
private TextView tv_process;

public int currentPross;//当前的进度

private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg){
switch (msg.what){
case DOWN_LOAD_ERROR:
Toast.makeText(getApplicationContext(), "下载失败", 0).show();
break;
case DOWN_LOAD_FINISH:
Toast.makeText(getApplicationContext(), "下载完成", 0).show();
break;
case SERVICE_ERROR:
Toast.makeText(getApplicationContext(), "服务器出错", 0).show();
break;
case UPDATE_TEXT:
tv_process.setText("当前进度："+pb.getProgress()*100/pb.getMax());
break;
}
}
};

@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.loader_layout);

et_path = (EditText) findViewById(R.id.loader_text);
pb = (ProgressBar) findViewById(R.id.loader_pb);
tv_process = (TextView) findViewById(R.id.tv_process);
}

public void downLoad(View v){
final String path = et_path.getText().toString().trim();
if (TextUtils.isEmpty(path)){
Toast.makeText(this, "下载路径错误", 0).show();
return ;
}
new Thread(){
public void run(){
//1.连接服务器，获取一个文件并获取该文件的大小
//在本地创建一个大小跟服务器文件一样大的临时文件
try {
//String path = "http://w.x.baidu.com/alading/anquan_soft_down_normal/13478/npp.6.6.9.Installer.1410249599.exe";
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5000);
conn.setRequestMethod("GET");
int code = conn.getResponseCode();
System.out.println("codemain:"+code);
if (code == 200){
//服务器返回的数据长度，实际上是文件的长度
int length = conn.getContentLength();
pb.setMax(length);//设置进度条的最大值
System.out.println("文件总长度："+length);

//在客户端本地创建出一个和服务器端大小一样的文件
RandomAccessFile raf = new RandomAccessFile("/sdcard/setup.exe", "rwd");
//指定创建的这个文件的长度
raf.setLength(length);
raf.close();

//计算出每个线程下载的文件大小
int blockSize = length / threadCount;

for (int threadId=1; threadId<=threadCount; threadId++){
//线程下载的开始位子
int startIndex = (threadId - 1) * blockSize;
//线程下载的结束位子
int endIndex = threadId * blockSize - 1;
if (threadId == threadCount){
endIndex = length;
}
System.out.println("线程"+threadId+"下载："+startIndex+"--->"+endIndex);
new DownloadThread(threadId, startIndex, endIndex, path).start();
}
}else{
Message msg = new Message();
msg.what = SERVICE_ERROR;
handler.sendMessage(msg);
System.out.println("服务器错误");
}
} catch (Exception e) {

e.printStackTrace();

Message msg = new Message();
msg.what = DOWN_LOAD_ERROR;
handler.sendMessage(msg);
}
}
}.start();
}

public class DownloadThread extends Thread{
private int threadId;
private int startIndex;
private int endIndex;
private String path;

public DownloadThread(int threadId, int startIndex, int endIndex,
String path) {
super();
this.threadId = threadId;
this.startIndex = startIndex;
this.endIndex = endIndex;
this.path = path;
}

@Override
public void run(){
try {
//检查是否存在记录下载长度的文件，如果存在读取这个文件的数据
File tempFile = new File("/sdcard/"+threadId+".txt");
if (tempFile.exists() && tempFile.length()>0){
FileInputStream fis = new FileInputStream(tempFile);
byte[] temp = new byte[1024];
//读取长度为temp长度的数据到temp中，返回的是读取数据的长度，读到文件末尾返回-1
int leng = fis.read(temp);
String downloadLen = new String(temp, 0, leng);
int downloadlenInt = Integer.parseInt(downloadLen);
int alreadyDownloadint = downloadlenInt - startIndex;
currentPross+=alreadyDownloadint;//获取已经下载的进度
startIndex = downloadlenInt;//修改下载的真实的开始位置
System.out.println("线程"+threadId+"真实下载位置："+startIndex+"--->"+endIndex);
fis.close();
}

URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
//请求服务器下载部分文件指定文件的位置
conn.setRequestProperty("Range","bytes="+startIndex+"-"+endIndex);
conn.setReadTimeout(5000);
/*
* 从服务器请求全部资源200 ok
* 如果从服务器请求部分资源206 ok
* */
int code = conn.getResponseCode();
System.out.println("code:"+code);
//已经设置了请求的位置，返回的是当前位置对应的文件输入流
InputStream is = conn.getInputStream();

RandomAccessFile raf = new RandomAccessFile("/sdcard/setup.exe", "rwd");
//随机写文件的时候从哪个位置开始写
raf.seek(startIndex);

int len = 0;
byte[] buffer = new byte[1024];
//已经下载的数据
int total = 0;

//记录当前线程下载数据的长度(方法一)
//File file = new File(threadId+".text");
while ((len = is.read(buffer)) != -1){
//FileOutputStream fos = new FileOutputStream(file);
//方法二
RandomAccessFile info = new RandomAccessFile("/sdcard/"+threadId+".txt", "rwd");
raf.write(buffer, 0, len);
total+=len;
info.write(String.valueOf(total+startIndex).getBytes());
info.close();

synchronized (MainActivity.this){
currentPross+=len;//获取当前的总进度
pb.setProgress(currentPross);//更改界面上progressbar进度条的进度
//特殊情况progressbar progressdialog进度条对话框可以直接在子线程里
//更新ui  内部代码特殊处理
//复用旧的消息避免过多的创建消息
Message msg =Message.obtain();
msg.what = UPDATE_TEXT;
handler.sendMessage(msg);
}
//fos.write(String.valueOf(total).getBytes());
//fos.close();
}
is.close();
raf.close();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
threadFinish();
}
}

private synchronized void threadFinish() {
runningThread--;
if (runningThread == 0){//所有线程下载完成
for (int i=1; i<=3; i++){
File file = new File("/sdcard/"+i+".txt");
file.delete();
}
System.out.println("文件下载完毕，删除所有的下载记录");
Message msg = new Message();
msg.what = DOWN_LOAD_FINISH;
handler.sendMessage(msg);
}
}
}

}