Java multi-threaded download file and breakpoint download

ImportJava.io.BufferedReader;ImportJava.io.File;ImportJava.io.FileInputStream;ImportJava.io.FileOutputStream;Importjava.io.IOException;ImportJava.io.InputStream;ImportJava.io.InputStreamReader;ImportJava.io.RandomAccessFile;Importjava.net.HttpURLConnection;ImportJava.net.URL;Importjavax.print.attribute.standard.Finishings; Public classMultidownload {Static intThreadCount = 3;//represents 3 Processes    Static intFinishedthread = 0;//record the number of files that are finished//Determine    StaticString Path = "Http://192.168.13.13:8080/QQPlayer.exe";  Public Static voidMain (string[] args) {//send a GET request to request resources for this address        Try{URL URL=NewURL (path); HttpURLConnection Conn=(HttpURLConnection) url.openconnection (); Conn.setrequestmethod ("GET"); Conn.setconnecttimeout (5000); Conn.setreadtimeout (5000); if(Conn.getresponsecode () = = 200){                //get the length of the requested resource file                intLength =conn.getcontentlength (); File File=NewFile ("QQPlayer.exe"); //Generate temporary FilesRandomaccessfile RAF =NewRandomaccessfile (file, "RWD"); //set the size of a temporary fileraf.setlength (length);                Raf.close (); //calculate how many bytes each thread should download                intSize = length/ThreadCount;  for(inti = 0; i < ThreadCount; i++) {                    //calculate start and end locations for thread downloads                    intStartIndex = i *size; intEndIndex = (i + 1) * size-1; //if it is the last thread, then the end position is written dead                    if(i = = ThreadCount-1) {EndIndex= Length-1; }//System.out.println ("thread" + i + "Download interval is:" + StartIndex + "---" + endIndex);                    NewDownloadthread (StartIndex, EndIndex, i). Start (); }            }        } Catch(Exception e) {//TODO auto-generated Catch blockE.printstacktrace (); }    }        }classDownloadthreadextendsthread{intStartIndex; intEndIndex; intthreadId;  PublicDownloadthread (intStartIndex,intEndIndex,intthreadId) {        Super();  This. StartIndex =StartIndex;  This. EndIndex =EndIndex;  This. ThreadId =threadId; } @Override Public voidrun () {//send HTTP request again, download original file        Try{File Progressfile=NewFile (threadId + ". txt"); //determine if the progress temp file exists            if(Progressfile.exists ()) {FileInputStream fis=NewFileInputStream (Progressfile); BufferedReader BR=NewBufferedReader (NewInputStreamReader (FIS)); //read the total progress of the last download from the progress temp file and add it to the original starting position to get a new start positionStartIndex + =Integer.parseint (Br.readline ());            Fis.close (); } System.out.println (The download interval for "thread" + ThreadId + "is:" + StartIndex + "---" +EndIndex);            HttpURLConnection Conn; URL URL=NewURL (Multidownload.path); Conn=(HttpURLConnection) url.openconnection (); Conn.setrequestmethod ("GET"); Conn.setconnecttimeout (5000); Conn.setreadtimeout (5000); //sets the interval of data requested by this HTTP requestConn.setrequestproperty ("Range", "bytes=" + StartIndex + "-" +EndIndex); //request part of the data, the corresponding code is 206            if(Conn.getresponsecode () = = 206){                //There's only 1/3 data in the stream at this time.InputStream is =Conn.getinputstream (); byte[] B =New byte[1024]; intLen = 0; intTotal = 0; //get the output stream for the temp fileFile File =NewFile ("QQPlayer.exe"); Randomaccessfile RAF=NewRandomaccessfile (file, "RWD"); //move the file's write location to startindexRaf.seek (StartIndex);  while(len = Is.read (b))! =-1){                    //synchronously writes data to a temporary file after each reading of the data in the streamRaf.write (b, 0, Len); Total+=Len;//System.out.println ("Threads" + threadId + "downloaded" + total); //generate a temporary file dedicated to recording the download progressRandomaccessfile Progressraf =NewRandomaccessfile (Progressfile, "RWD"); //synchronously writes the total progress of the current thread download to the progress temp file after each reading of the data in the streamProgressraf.write (Total + ""). GetBytes ());                Progressraf.close (); } System.out.println ("Thread" + threadId + "Download-------------------the little volunteers! ");                                Raf.close (); //Delete the file of the recording process must all 3 processes download complete before you can deletemultidownload.finishedthread++; synchronized(Multidownload.path) {//thread security issues, static variables are unique                    if(Multidownload.finishedthread = =Multidownload.threadcount) {                         for(inti = 0; i < Multidownload.threadcount; i++) {File F=NewFile (i + ". txt");                        F.delete (); } multidownload.finishedthread= 0; }                }                            }        } Catch(Exception e) {//TODO auto-generated Catch blockE.printstacktrace (); }    }}

Java multi-threaded download file and breakpoint download