duoxancheng.txt

次JAVA程序支持多线程下载

{
private long startPos;//下载起点
private long endPos;//下载结束点
private boolean done = false;
private boolean stop=false;
private String address;//下载地址
private DownloadStat stat;//统计线程 
private RandomAccessFile file=null;

public DownThread(String address,String localFilePath,long startPos, long endPos,DownloadStat stat) throws IOException
{
   this.address = address;
   this.startPos = startPos;
   this.endPos = endPos;
   this.address=address;
   file=new RandomAccessFile(localFilePath, "rw");
   file.seek(startPos);//设置启动位置
   this.stat=stat; 
}

public void run()
{
   InputStream input =null;
   HttpURLConnection httpConnection=null;
   try
   {
    httpConnection = (HttpURLConnection) new URL(address).openConnection();
    if(httpConnection==null)
    {
     return;
    }
    String sProperty = new StringBuffer("bytes=").append(startPos).append("-").append(endPos).toString();
    httpConnection.setRequestProperty("RANGE", sProperty);//设置下载范围
    input =httpConnection.getInputStream();
    byte[] buf=new byte[1024];
    int offset;
    while(!stop&&(offset=input.read(buf,0,buf.length))!=-1)
    {
     file.write(buf, 0,offset);
     stat.updateDownloadSize(getName(),startPos,endPos,offset);//将下载的数据量进行累加
    }
   }
   catch (Exception ex)
   {
    ex.printStackTrace();
   }
   finally
   {
    try
    {
     file.close();
     if(input!=null)
     {
      input.close();
     }
    }
    catch (IOException e)
    {
     e.printStackTrace();
    }
    done = true;
    if(httpConnection!=null)
    {
     httpConnection.disconnect();
    }
   }
}
/**
* 判断是否完成
* @return
*/
public boolean isDone()
{
   return done;
}
/**
* 终止下载
*/
public void stopDown()
{
   this.stop=true;
}
}
/**
* 下载统计类
* 包括已经下载的数据量、下载平均速度、已经下载时间、完成百分比等等
* @author zean
* @create date 2008-06-30
*/
public class DownloadStat extends Thread
{
private long beginTime;//本次下载开始时间
private BigDecimal downloadedSize;//本次下载量累计
private long fileLength;//文件长度
private BigDecimal initSpeed;
private boolean stopStat=false;
private DownloadHis downloadHis;
private String fileName;
/**
* @param fileLength 文件长度
* @param downloadHis 下载历史信息
*/
public void init(long fileLength,String fileName)
{
   this.beginTime=System.currentTimeMillis();
   this.downloadedSize=new BigDecimal(0);
   this.fileLength=fileLength;
   this.initSpeed=new BigDecimal(0);
   this.fileName=fileName;
   if(downloadHis==null)
   {
    downloadHis=new DownloadHis(fileName);
   }
   else
   {
    downloadHis.initDownloadedInfo(fileName);
   }
}
public boolean isDownloaded()
{
   if((int)downloadHis.getHisPercent()==10000)
   {
    return true;
   }
   return false;
}

/**
* 定时将下载信息写入磁盘,由于文件下载完毕后也有写入操作，所以写入方法加了同步锁
*/
public void run()
{
   while(!stopStat)
   {
    try
    {
     sleep(30000);//隔30秒自动写入一次
    }
    catch (InterruptedException e)
    {
     e.printStackTrace();
    }
    /**
    * 下载完成一个文件后暂停自动写入操作
    */
    if(isDownloaded()||getPercent().intValue()==100)
    {
     try
     {
      synchronized(this)
      {
       wait();
      }
     }
     catch (InterruptedException e)
     {
      e.printStackTrace();
     }
    }
    if(getSpeed().doubleValue()>0)
    {
     writeDownInfoToFile();
    }
   }
}
public void stopStat()
{
   this.stopStat=true;
}
/**
* 更新下载数据量(单位:字节)以及下载起始位置
* 由于可能同时有多个线程进行操作，所以加同步锁
* @param signalDownSize
*/
public synchronized void updateDownloadSize(String threadId,long startPos,long endPos,long size)
{
   downloadedSize=downloadedSize.add(new BigDecimal(size));
   downloadHis.updateDownInfo(threadId,startPos,endPos,size);
}
public void initDownInfo(String threadId,long startPos,long endPos)
{
   downloadHis.updateDownInfo(threadId,startPos,endPos,0);
}
/**
* 获取已经下载的数据量(单位:M)
* @return
*/
public BigDecimal getDownloadedSize()
{
   return (downloadedSize.add(downloadHis.getHisDownloadedSize())).divide(new BigDecimal(1048576),2,BigDecimal.ROUND_HALF_UP);
}

/**
* 已经下载时间(时-分-秒)
*/
public String getPassedTime()
{
   return parseTime(new BigDecimal(System.currentTimeMillis()-beginTime));
}
/**
* 获取下载百分比
* @return
*/
public BigDecimal getPercent()
{
   return (downloadedSize.add(downloadHis.getHisDownloadedSize())).multiply(new BigDecimal(100)).divide(new BigDecimal(fileLength), 2, BigDecimal.ROUND_HALF_UP);
}
/**
* 下载平均速度(K/秒)
* @return
*/
public BigDecimal getDownSpeed()
{
   return getSpeed().multiply(new BigDecimal(1000)).divide(new BigDecimal(1024), 1, BigDecimal.ROUND_HALF_UP);
}
/**
* 下载平均速度(字节/毫秒)
* @return
*/
private BigDecimal getSpeed()
{
   BigDecimal timeOffset=new BigDecimal(System.currentTimeMillis()-beginTime);
   if(timeOffset.longValue()==0)
   {
    return initSpeed;
   }
   return downloadedSize.divide(timeOffset,1,BigDecimal.ROUND_HALF_UP);
}
/**
* 估计剩余时间(时-分-秒)
* @param timespace
* @return
*/
public String getLeaveTime()
{
   if(getSpeed().intValue()<1)
   {
    return "0";
   }
   BigDecimal leaveTime=(new BigDecimal(fileLength).subtract(downloadedSize).subtract(this.downloadHis.getHisDownloadedSize())).divide(getSpeed(), 2, BigDecimal.ROUND_HALF_UP);
   return parseTime(leaveTime);
}
/**
* 将下载信息写入磁盘
*/
public synchronized void writeDownInfoToFile()
{
   downloadHis.writeDownInfoToFile(fileLength, downloadedSize,getPercent().doubleValue());
}
/**
* 获取历史下载信息
* @return
*/
public List getDownloadedInfo()
{
   return this.downloadHis.getDownloadedInfo();
}
/**
* 判断服务器文件是否发生变化
* @return
*/
public boolean isChange()
{
   return (downloadHis.getHisFileLength()!=0&&fileLength!=downloadHis.getHisFileLength());
}
public String getFileName()
{
   return this.fileName;
}
/**
* 获取历史下载百分比
* @return
*/
public int getHisPercent()
{
   return downloadHis.getHisPercent();
}
/**
* 解析时间成 时-分-秒的形式
* @param timeOffset
* @return
*/
private String parseTime(BigDecimal timeOffset)
{
   BigDecimal times=timeOffset.divide(new BigDecimal(1000), 1, BigDecimal.ROUND_HALF_UP);
   BigDecimal hours = times.divide(new BigDecimal(3600), 0, BigDecimal.ROUND_DOWN);
   BigDecimal mimutes = times.subtract(hours.multiply(new BigDecimal(3600))).divide(new BigDecimal(60), 0, BigDecimal.ROUND_DOWN);
   BigDecimal second = times.subtract(hours.multiply(new BigDecimal(3600))).subtract(mimutes.multiply(new BigDecimal(60)));
   return hours.longValue() + "时," + mimutes.longValue() + "分," + second.doubleValue() + "秒";
}
}
/**
* 下载历史记录
* 用于记录下载量，各线程下载情况，以及将下载信息写入到本地磁盘
* @author zean
* @crate date 2008-07-01
*/
public class DownloadHis
{
private List downloadedInfo;// 历史线程下载记录
private BigDecimal hisDownloadedSize;//历史下载量
private long hisFileLength=0;//历史文件大小，由于源文件大小有可能发生变化，一旦文件大小与当前大小不一致，则需要重新下载
private Map infoMap=null;//
private String fileName=null;
private int hisPercent=0;//历史下载百分比
public DownloadHis()
{
   infoMap=new HashMap();
}
public DownloadHis(String fileName)
{
   this.fileName=fileName;
   infoMap=new HashMap();
   initDownloadedInfo(fileName);
}

/**
* 初始化历史下载信息
*/
public void initDownloadedInfo(String fileName)
{
   downloadedInfo=null;
   hisDownloadedSize=new BigDecimal(0);
   infoMap.clear();
   hisFileLength=0;
   hisPercent=0;
   this.fileName=fileName;
   SAXReader reader=new SAXReader();
   File file=new File(getFilePath(fileName));
   if(!file.exists())
   {
    return;
   }
   Document doc=null;
   try
   {
    doc = reader.read(file);
   }
   catch (DocumentException e)
   {
    e.printStackTrace();
   }
   Element root=doc.getRootElement();
   List elements=root.elements();
   if(elements==null||elements.size()<1)
   {
    return;
   }
   List list=new ArrayList();
   Element element=null;
   setHisPercent(root.attributeValue("percent"));
   setHisDownloadedSize(root.attributeValue("downloadedSize"));
   setHisFileLength(root.attributeValue("totalSize"));
   for(int i=0;i<elements.size();i++)
   {
    element=(Element)elements.get(i);
    long startPos=Long.parseLong(element.attributeValue("startPos"));
    long endPos=Long.parseLong(element.attributeValue("endPos"));
    if(startPos<=endPos)
    {
     list.add(new DownInfo(element.attributeValue("threadId"),startPos,endPos));
    }
   }
   setDownloadedInfo(list);
}

/**
* 将下载信息写入磁盘
*/
protected void writeDownInfoToFile(long fileLength,BigDecimal downloadedSize,double downPercent)
{
   if(!new File(UpdateService.getTempFolder()+fileName).exists())
   {
    return;
   }
   StringBuffer buf=new StringBuffer();
   buf.append("<?xml version=\"1.0\" encoding=\"GB2312\"?>").append("\n<threads totalSize=\""+fileLength+"\" downloadedSize=\""+downloadedSize.add(getHisDownloadedSize()).longValue()+"\" percent=\""+downPercent+"\">\n");
   Set set=infoMap.entrySet();
   Iterator it=set.iterator();
   Map.Entry entry;
   DownInfo downInfo;
   while(it.hasNext())
   {
    entry=(Map.Entry)it.next();
    downInfo=(DownInfo)entry.getValue();
    buf.append("<thread threadId=\""+entry.getKey()+"\" startPos=\""+downInfo.getStartPos()+"\" endPos=\""+downInfo.getEndPos()+"\"></thread>\n");
   }
   buf.append("</threads>");
   FileWriter fw = null;
   try
   {
    fw = new FileWriter(getFilePath(fileName));
    fw.write(buf.toString(), 0, buf.length());
    fw.close();
   }
   catch (IOException e1)
   {
    e1.printStackTrace();
   }
}
/**
* 更新线程下载信息
* @param infoMap 封装了各个线程的下载情况
* @param threadId 线程名
* @param startPos 起点位置
* @param endPos 终点位置
* @param size 即时下载量
*/
public void updateDownInfo(String threadId,long startPos,long endPos,long size)
{
   DownInfo downInfo=(DownInfo)infoMap.get(threadId);
   if(downInfo==null)
   {
    downInfo=new DownInfo(threadId,startPos,endPos);
   }
   else
   {
    downInfo.updateStartPos(size);
   }
   infoMap.put(threadId,downInfo);
}

private void setDownloadedInfo(List downloadedInfo)
{
   this.downloadedInfo = downloadedInfo;
}
/**
* 读取上次下载的信息作为断点续传的基础
* @return
* @throws DocumentException
*/
public List getDownloadedInfo()
{
   return downloadedInfo;
}
/**
* 获取历史下载百分比
* @return
*/
public int getHisPercent()
{
   return this.hisPercent;
}
private void setHisPercent(String percent)
{
   if(percent!=null)
   {
    this.hisPercent=new BigDecimal(percent).multiply(new BigDecimal(100)).intValue();
   }
}
/**
* 获取历史下载量
* @return
*/
public BigDecimal getHisDownloadedSize()
{
   return hisDownloadedSize;
}
private void setHisDownloadedSize(String hisDownloadedSize)
{
   if(hisDownloadedSize!=null)
   {
    this.hisDownloadedSize = new BigDecimal(hisDownloadedSize);
   }
}
/**
* 获取历史文件长度(用于下载前与当前下载文件进行比较)
* @return
*/
public long getHisFileLength()
{
   return hisFileLength;
}
private void setHisFileLength(String hisFileLength)
{
   if(hisFileLength!=null)
   {
    this.hisFileLength = Long.parseLong(hisFileLength);
   }
}
/**
* 获取历史记录信息文件地址
* @param fileName
* @return
*/
private String getFilePath(String fileName)
{
   return UpdateService.getTempFolder()+fileName+".xml";
}
/**
* 获取下载文件名
* @return
*/
public String getFileName()
{
   return this.fileName;
}
}