Multithreading download files from the network

Main class:

1  Public classDownthreaddemo {2 3      Public Static voidMain (string[] args) {4         //TODO auto-generated Method Stub5         intThreadnum = 3;6         LongFileLen = 0;7         LongNumperthread = 0;8         Longleft = 0;9URL url =NULL;TenURLConnection connection =NULL; OneString fileName = "E:\\temp\\downlo.jpg"; ARandomaccessfile[] RAF =NewRandomaccessfile[threadnum]; -Inputstream[] is =NewInputstream[threadnum]; -         Try { theURL =NewURL ( -"Http://img.bizhi.sogou.com/images/2014/08/22/830201.jpg"); -             //Open Network Connection -Connection =url.openconnection (); +             //Calculate File Size -FileLen =Connection.getcontentlengthlong (); +             //file sizes processed per thread ANumperthread = FileLen/threadnum; at             //last piece -left = fileLen%threadnum; -             //openconnection (). getInputStream () -Is[0] =Url.openstream (); -Raf[0] =NewRandomaccessfile (FileName, "RW"); -Raf[0].setlength (fileLen); in             //Create a stream that reads from the network and writes to the file for each thread, respectively.  -              for(inti = 0; i < threadnum; i++) { to                 if(I! = 0) { +Is[i] =Url.openstream (); -Raf[i] =NewRandomaccessfile (FileName, "RW"); the                 } *                 if(i = = ThreadNum-1) { $                     NewMultydown (i * numperthread, (i + 1) *NumperthreadPanax Notoginseng+Left , Is[i], Raf[i]). Start (); -}Else { the                     NewMultydown (i * numperthread, (i + 1) *Numperthread, + Is[i], Raf[i]). Start (); A                 } the             } +}Catch(malformedurlexception e) { -             //TODO auto-generated Catch block $ e.printstacktrace (); $}Catch(IOException e) { -             //TODO auto-generated Catch block - e.printstacktrace (); the         } -SYSTEM.OUT.PRINTLN ("End------");Wuyi     } the  -}

Thread class:

1  Public classMultydownextendsThread {2     Private Longstart, end;3     PrivateInputStream is;4     PrivateRandomaccessfile RAF;5 6      PublicMultydown () {7         //TODO auto-generated Constructor stub8     }9 Ten      PublicMultydown (LongStartLongend, InputStream is, Randomaccessfile RAF) { One         //TODO auto-generated Constructor stub A          This. Start =start; -          This. end =end; -          This. is =is ; the          This. RAF =RAF; -     } -  - @Override +      Public voidrun () { -         //TODO auto-generated Method Stub +  A         intLen = 0; at         intSize = 0; -         byte[] B =New byte[24]; -         Try { -             //jump to file specified location - Is.skip (start); - Raf.seek (start); in              while(len = Is.read (b))! =-1 && size < (end-start)) { -Raf.write (b, 0, Len); toSize + =Len; +             } -}Catch(IOException e) { the             //TODO auto-generated Catch block * e.printstacktrace (); $}finally {Panax Notoginseng             if(Is! =NULL) { -                 Try { the is.close (); +}Catch(IOException e) { A                     //TODO auto-generated Catch block the e.printstacktrace (); +                 } -             } $             if(RAF! =NULL) { $                 Try { - raf.close (); -}Catch(IOException e) { the                     //TODO auto-generated Catch block - e.printstacktrace ();Wuyi                 } the             } -         } Wu     } -  About}

Multithreading download files from the network