Multi-threaded breakpoint continuation of the demo

import java.io.bufferedreader;import java.io.file;import java.io.fileinputstream;import  java.io.inputstream;import java.io.inputstreamreader;import java.io.randomaccessfile;import  The principle of java.net.httpurlconnection;import java.net.url;/** *     multi-threaded breakpoint continuation transmission  * 1 , when the multi-threaded abrupt interruption, in the cache file to save the location of the interrupt,  * 2, when the continuation of the time, read the location in the cache file, and then as the beginning of the location to download.  *  @author  Sheamus * */public class MutilHttpDownload {     //the number of threads completed downloading     static int finishedThread = 0;     static String path =  "Http://10.31.2.6:8080/demo/QQ.exe";     static int processnum = 3;        public  static void main (String[] args)  {        // Request the size of the file and create a cache file of the same size         try {            url url =  new url (path);             // Create a QQ.exe file in the project directory             file file  = new file ("QQ.exe");             Randomaccessfile raf = new randomaccessfile (file,  "RWD");                          HttpURLConnection conn =  (HttpURLConnection)  url.openconnection ();             conn.setrequestmethod ("GET");             conn.setreadtimeout (;     )       &nbsP;conn.setreadtimeout (;             )            if (Conn.getresponsecode ()  == 200)  {                int  length = conn.getcontentlength ();                 //setting the size of the cache file                  raf.setlength (length);                 raf.close ();                 //calculate the size that each thread should download                  int size = length / PROCESSNUM;                 //calculates where each thread starts and ends                  for (int i = 0; i  < processnum; i++)  {                                          int startindex = i * size ;                     int endIndex =  (i + 1)  * size - 1;                     // At the time of the last thread, the last position was the total length minus 1              .     &nBsp; if (i ==  (processnum - 1))  {                         endIndex  = length - 1;                     }                     //start thread execution Download                      new singledownloadthread ( startindex,endindex,i). Start ();                 }            }                     }  catch  (EXCEPTION&NBsp;e)  {            // TODO  auto-generated catch block             E.printstacktrace ();        }    }}class  singledownloadthread extends thread {    private int startindex;     private int endIndex;    private int  Currentthreadid;    public singledownloadthread (int startindex, int  Endindex, int currentthreadid)  {        super ();         this.startIndex = startIndex;         this.endIndex = endIndex;         This.currentthreadid = currentthreadid;    }     @Override     public string  tostring ()  {        return  "downloadthread [ startindex= " + startIndex + ",  endindex= "                 + endIndex +  ",  currentthreadid="  + currentThreadId +  "]";    }     @Override      public void run ()  {        int  total = 0;        //Download the part of the thread to download          try {            // Define the cache file to save the downloaded location             file tempfile  = new file ("Temp"   + currentthreadid + ". txt");             if (tempfile.exists ())  {                 //download, if there is a cache file, read the cached file, replace this number with the starting position                  fileinputstream fis = new fileinputstream ( Tempfile);                 Bufferedreader bis = new bufferedreader (New inputstreamreader (FIS));                 int tempstartindex  = integer.parseint (Bis.readline ());                 startIndex = tempStartIndex;             &nBsp;   fis.close ();             }             system.out.println ("The download interval is  :"  + startindex + " -- > "  + endindex + "------------------------- -------");            file file =  New file ("QQ.exe");             Randomaccessfile raf = new randomaccessfile (file,  "RWD");                          url url = new url (Mutilhttpdownload.path);                          httpurlconnection conn = (httpurlconnection)  url.openconnection ();             conn.setrequestmethod ("GET");             conn.setconnecttimeout (;            ) Conn.setreadtimeout (            //); Set the section to download             conn.setrequestproperty ("Range",  "Bytes="  + startIndex +  "-"  + endindex);             //will randomly read a pointer to the stream that reads the file to the beginning of the file to be read              raf.seek (StartIndex);             //partial file Gets the successful return code is 206&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;IF (Conn.getresponsecode ()  ==  206)  {                 Inputstream in = conn.getinputstream ();                 byte[] b = new byte[1024];                 int len = 0;                 while (len  = in.read (b))  != -1)  {                     raf.write (B, 0, len);                     total  += len;                     systeM.out.println ("Threads  "  + currentThreadId +  "downloaded  "  + total);                     // Create an output stream write out where you are currently reading                      randomaccessfile tempraf = new randomaccessfile (TempFile,   "RWD");                     tempraf.write ((total+ ""). GetBytes ());                     tempraf.close ();                 }                 system.out.println ("Threads  "  +  currentthreadid + "Download done!");                 raf.close ();                                   mutilhttpdownload.finishedthread++;                 synchronized  (Mutilhttpdownload.path)  {                     if ( Mutilhttpdownload.finishedthread == mutilhttpdownload.processnum)  {                          for (int i = 0; i < mutilhttpdownload.processnum; i++)  {           &nbsP;                 file  f = new file ("Temp"  + i +  ". txt");                              system.out.println ("delete"  + f.getname ()  + "file");                              f.delete ();                         }                          //only let one thread come in and delete the file, otherwise it will be abnormal                          mutilhttpdownload.finishedthread = 0;                     }                 }             }                     } catch  (exception e)  {             // TODO Auto-generated  Catch block            e.printstacktrace ();         }                     }}

Multi-threaded breakpoint continuation of the demo