sitefilefetch.java

用java实现的断点续传源代码

 /*   
  **SiteFileFetch.java   
  */   
  package   NetFox;   
  import   java.io.*;   
  import   java.net.*;   
    
    
  public   class   SiteFileFetch   extends   Thread   {   
    
    
  SiteInfoBean   siteInfoBean   =   null;   //文件信息Bean   
  long[]   nStartPos;   //开始位置   
  long[]   nEndPos;   //结束位置   
  FileSplitterFetch[]   fileSplitterFetch;   //子线程对象   
  long   nFileLength;   //文件长度   
  boolean   bFirst   =   true;   //是否第一次取文件   
  boolean   bStop   =   false;   //停止标志   
  File   tmpFile;   //文件下载的临时信息   
  DataOutputStream   output;   //输出到文件的输出流   
    
    
  public   SiteFileFetch(SiteInfoBean   bean)   throws   IOException   
  {   
  siteInfoBean   =   bean;   
  //tmpFile   =   File.createTempFile   ("zhong","1111",new   File(bean.getSFilePath()));   
  tmpFile   =   new   File(bean.getSFilePath()+File.separator   +   bean.getSFileName()+".info");   
  if(tmpFile.exists   ())   
  {   
  bFirst   =   false;   
  read_nPos();   
  }   
  else   
  {   
  nStartPos   =   new   long[bean.getNSplitter()];   
  nEndPos   =   new   long[bean.getNSplitter()];   
  }   
    
    
    
  }   
    
    
  public   void   run()   
  {   
  //获得文件长度   
  //分割文件   
  //实例FileSplitterFetch   
  //启动FileSplitterFetch线程   
  //等待子线程返回   
  try{   
  if(bFirst)   
  {   
  nFileLength   =   getFileSize();   
  if(nFileLength   ==   -1)   
  {   
  System.err.println("File   Length   is   not   known!");   
  }   
  else   if(nFileLength   ==   -2)   
  {   
  System.err.println("File   is   not   access!");   
  }   
  else   
  {   
  for(int   i=0;i<nStartPos.length;i++)   
  {   
  nStartPos[i]   =   (long)(i*(nFileLength/nStartPos.length));   
  }   
  for(int   i=0;i<nEndPos.length-1;i++)   
  {   
  nEndPos[i]   =   nStartPos[i+1];   
  }   
  nEndPos[nEndPos.length-1]   =   nFileLength;   
  }   
  }   
    
    
  //启动子线程   
  fileSplitterFetch   =   new   FileSplitterFetch[nStartPos.length];   
  for(int   i=0;i<nStartPos.length;i++)   
  {   
  fileSplitterFetch[i]   =   new   FileSplitterFetch(siteInfoBean.getSSiteURL(),   
  siteInfoBean.getSFilePath()   +   File.separator   +   siteInfoBean.getSFileName(),   
  nStartPos[i],nEndPos[i],i);   
  Utility.log("Thread   "   +   i   +   "   ,   nStartPos   =   "   +   nStartPos[i]   +   ",   nEndPos   =   "   +   nEndPos[i]);   
  fileSplitterFetch[i].start();   
  }   
  //   fileSplitterFetch[nPos.length-1]   =   new   FileSplitterFetch(siteInfoBean.getSSiteURL(),   
  siteInfoBean.getSFilePath()   +   File.separator   +   siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);   
  //   Utility.log("Thread   "   +   (nPos.length-1)   +   "   ,   nStartPos   =   "   +   nPos[nPos.length-1]   +   ",   
  nEndPos   =   "   +   nFileLength);   
  //   fileSplitterFetch[nPos.length-1].start();   
    
    
  //等待子线程结束   
  //int   count   =   0;   
  //是否结束while循环   
  boolean   breakWhile   =   false;   
    
    
  while(!bStop)   
  {   
  write_nPos();   
  Utility.sleep(500);   
  breakWhile   =   true;   
    
    
  for(int   i=0;i<nStartPos.length;i++)   
  {   
  if(!fileSplitterFetch[i].bDownOver)   
  {   
  breakWhile   =   false;   
  break;   
  }   
  }   
  if(breakWhile)   
  break;   
    
    
  //count++;   
  //if(count>4)   
  //   siteStop();   
  }   
    
    
  System.err.println("文件下载结束！");   
  }   
  catch(Exception   e){e.printStackTrace   ();}   
  }   
    
    
  //获得文件长度   
  public   long   getFileSize()   
  {   
  int   nFileLength   =   -1;   
  try{   
  URL   url   =   new   URL(siteInfoBean.getSSiteURL());   
  HttpURLConnection   httpConnection   =   (HttpURLConnection)url.openConnection   ();   
  httpConnection.setRequestProperty("User-Agent","NetFox");   
    
    
  int   responseCode=httpConnection.getResponseCode();   
  if(responseCode>=400)   
  {   
  processErrorCode(responseCode);   
  return   -2;   //-2   represent   access   is   error   
  }   
    
    
  String   sHeader;   
    
    
  for(int   i=1;;i++)   
  {   
  //DataInputStream   in   =   new   DataInputStream(httpConnection.getInputStream   ());   
  //Utility.log(in.readLine());   
  sHeader=httpConnection.getHeaderFieldKey(i);   
  if(sHeader!=null)   
  {   
  if(sHeader.equals("Content-Length"))   
  {   
  nFileLength   =   Integer.parseInt(httpConnection.getHeaderField(sHeader));   
  break;   
  }   
  }   
  else   
  break;   
  }   
  }   
  catch(IOException   e){e.printStackTrace   ();}   
  catch(Exception   e){e.printStackTrace   ();}   
    
    
  Utility.log(nFileLength);   
    
    
  return   nFileLength;   
  }   
    
    
  //保存下载信息（文件指针位置）   
  private   void   write_nPos()   
  {   
  try{   
  output   =   new   DataOutputStream(new   FileOutputStream(tmpFile));   
  output.writeInt(nStartPos.length);   
  for(int   i=0;i<nStartPos.length;i++)   
  {   
  //   output.writeLong(nPos[i]);   
  output.writeLong(fileSplitterFetch[i].nStartPos);   
  output.writeLong(fileSplitterFetch[i].nEndPos);   
  }   
  output.close();   
  }   
  catch(IOException   e){e.printStackTrace   ();}   
  catch(Exception   e){e.printStackTrace   ();}   
  }   
    
    
  //读取保存的下载信息（文件指针位置）   
  private   void   read_nPos()   
  {   
  try{   
  DataInputStream   input   =   new   DataInputStream(new   FileInputStream(tmpFile));   
  int   nCount   =   input.readInt();   
  nStartPos   =   new   long[nCount];   
  nEndPos   =   new   long[nCount];   
  for(int   i=0;i<nStartPos.length;i++)   
  {   
  nStartPos[i]   =   input.readLong();   
  nEndPos[i]   =   input.readLong();   
  }   
  input.close();   
  }   
  catch(IOException   e){e.printStackTrace   ();}   
  catch(Exception   e){e.printStackTrace   ();}   
  }   
    
    
  private   void   processErrorCode(int   nErrorCode)   
  {   
  System.err.println("Error   Code   :   "   +   nErrorCode);   
  }   
    
    
  //停止文件下载   
  public   void   siteStop()   
  {   
  bStop   =   true;   
  for(int   i=0;i<nStartPos.length;i++)   
  fileSplitterFetch[i].splitterStop();   
    
    
  }   
  }