Java implementation multi-threaded download

1  PackageCn.test.DownLoad;2 3 ImportJava.io.File;4 ImportJava.io.InputStream;5 ImportJava.io.RandomAccessFile;6 Importjava.net.HttpURLConnection;7 ImportJava.net.URL;8 9  Public classMultiPart {Ten      Public voidDown ()throwsException One     { A         //1. Declaration URL -String filename= "A.rar"; -String path= "http://localhost:8080/day23_MultiThreadDownLoad/file/" +FileName; theURL url=NewURL (path); -         //2. Return to the Connection object -HttpURLConnection conn=(HttpURLConnection) url.openconnection (); -         //3. Set the request type +Conn.setrequestmethod ("GET"); -         //4. Set allow messages to be received +Conn.setdoinput (true); A         //5. Connection at Conn.connect (); -         //6. Status Code -         intCode=Conn.getresponsecode (); -         if(code==200) -         { -             intSum=conn.getcontentlength ();//Total length inString downfile= "d:\\" +FileName; -             //7. Create an empty file of the same size toRandomaccessfile file=NewRandomaccessfile (NewFile (Downfile), "RW"); + file.setlength (sum); - file.close (); the             //8. Declaring the number of threads *             intThreadcount=3; $             //9. Declare the download volume for each threadPanax Notoginseng             intthreadsize=sum/threadcount+ ((sum%threadcount==0)? 0:1); -              for(inti=0;i<threadcount;i++) the             { +                 intstart=i*threadsize; A                 intEnd=start+threadsize-1; theSystem.out.println ("Thread:" +i+ ":" +start+ ":" +end); +                 //10. Start Thread -                 NewMyThread (Start,end,downfile,url). Start (); $             }         $         } -         //11. Close the connection - Conn.disconnect (); the     } -     Wuyi      Public Static voidMain (string[] args) { the         Try { -             NewMultiPart (). Down (); Wu}Catch(Exception e) { - e.printstacktrace (); About         } $System.out.println ("OK"); -     } - } -  A classMyThreadextendsThread + { the     Private intstart; -     Private intend; $     PrivateString Downfile; the     PrivateURL url;  the      PublicMyThread (intStartintend, String downfile, url url) { the          This. Start =start; the          This. end =end; -          This. Downfile =Downfile; in          This. url =URL; the     } the  About      Public voidrun () { the         Try { theHttpURLConnection conn=(HttpURLConnection) url.openconnection (); theConn.setrequestmethod ("GET"); +Conn.setdoinput (true); -             //settings from where to download. Breakpoint theConn.setrequestproperty ("Range", "bytes=" +start+ "-" +end);Bayi Conn.connect (); the             intCode=Conn.getresponsecode (); the             if(code==206) -             { -                 intSize=conn.getcontentlength (); theInputStream in=Conn.getinputstream (); the                 //write the same file theRandomaccessfile file=NewRandomaccessfile (NewFile (Downfile), "RW"); the                 //set where to start writing from a file - File.seek (start); the                 byte[] b=New byte[1024]; the                 intLen=-1; the                  while((Len=in.read (b))!=-1)94                 { theFile.write (b, 0, Len); the                 } the file.close ();98             } About Conn.disconnect ();  -             101}Catch(Exception e) {102 e.printstacktrace ();103         }        104     }     the}

Java implementation multi-threaded download