Java multi-threaded file download

The following code is a bit of a problem, there will be blocking, do not know what the problem:

 packagecom.test.service;Importjava.io.File;Importjava.io.InputStream;Importjava.io.RandomAccessFile;Importjava.net.HttpURLConnection;Importjava.net.URL;Importjava.util.concurrent.CountDownLatch;Importorg.slf4j.Logger;Importorg.slf4j.LoggerFactory;Importorg.springframework.beans.factory.annotation.Value;Importorg.springframework.stereotype.Component;/*** <p> * multi-threaded file download, improve the download speed of large files (not used) * <p> **/@Component public classMulitthreaddownload {Private StaticLogger Logger = Loggerfactory.getlogger (mulitthreaddownload.class); @Value ("${onair.download.threadsize:5}")    Private intThreadsize = 5; @Value ("${onair.download.timeout:5000}")    Private intdownloadtimeout; Static BooleanFlag =true; //message    Private FinalCountdownlatch Msgdownlatch =NewCountdownlatch (1); //Worker Threads    Private FinalCountdownlatch Workdownlatch =NewCountdownlatch (threadsize); Privatedowloadrunnable[] Dowloadrunnables =Newdowloadrunnable[threadsize];  public Static voidmain (string[] Args) {NewMulitthreaddownload (). downloadFile ("", "g:\\123.mp4"); }         public BooleandownloadFile (String url,string filePath) {logger.debug (": {}, destination file path: {}", url,filepath); Try{URL URLPath=NewURL (url); HttpURLConnection Conn=(httpurlconnection) urlpath.openconnection ();            Conn.setconnecttimeout (downloadtimeout); Conn.setrequestmethod ("GET"); intStatus =Conn.getresponsecode (); if(status = = 200) {//200 return all, 206 return part//file Length                intLength =Conn.getcontentlength (); Logger.info ("get file Size: {}", length); //Create download file specify sizeRandomaccessfile RAF =NewRandomaccessfile (NewFile (filePath), "rwd");                Raf.setlength (length); Raf.close (); //Freeing Resources//chunking size                intBlockSize = length/threadsize; //Create worker Threads                 for(inti = 1; I <= threadsize; i++) {                    intStartIndex = blocksize* (i-1); intEndIndex = blockSize * i-1; if(i = =Threadsize) {endIndex=length; } logger.info ("thread: {} Download file start point: {} end Point: {}", i,startindex,endindex); Dowloadrunnables[i-1] =Newdowloadrunnable (url,filepath,msgdownlatch, workdownlatch, i,startindex,endindex); Thread Thread=NewThread (dowloadrunnables[i-1]);                    Thread.Start (); Thread.setuncaughtexceptionhandler (NewThread.uncaughtexceptionhandler () {@Override public voiduncaughtexception (Thread t, throwable e) {logger.debug ("catch to exception", e); Flag=false;                                    }                    }); }                //notify worker thread to start, start workingMsgdownlatch.countdown (); Logger.debug ("main thread blocked, waiting for worker threads to complete task"); //start a thread to monitor the download progress//Moniterlength (length); //block the main thread, waiting for the worker thread to finishworkdownlatch.await (); Logger.debug ("worker threads complete task, main thread continues"); returnflag; }                    } Catch(throwable e) {logger.error ("file Download failed:" +e.getmessage (), e); File File=NewFile (filePath); if(file.exists ()) {file.delete ();//Download failed to delete temp file            }        }        return false; }    //Output Download Progress    Private voidMoniterlength (intLength) {        NewThread (NewRunnable () {@Override public voidRun () { while(getdownloadlength () <Length) {logger.debug ("file size: {}, Current Download size: {}, progress {}", length,getdownloadlength (), getdownloadlength () * 1.0/(Long) length); Try{thread.sleep (10000); } Catch(interruptedexception E) {//TODO auto-generated Catch blockE.printstacktrace ();    }}}). Start (); }    //Monitor Download Progress     public intgetdownloadlength () {intLength = 0;  for(inti = 0; I < dowloadrunnables.length; i++) {length+=dowloadrunnables[i].downloadlength; }        returnlength; }    }//Download ThreadclassDowloadrunnableImplementsrunnable{Private StaticLogger Logger = Loggerfactory.getlogger (dowloadrunnable.class); PrivateCountdownlatch msgdownlatch; PrivateCountdownlatch workdownlatch; Private intthreadindex; Private intstartIndex; Private intendIndex; PrivateString url; PrivateString filePath;  public intdownloadlength;//Downloaded size         publicdowloadrunnable (string url, string filePath, countdownlatch msgdownlatch, countdownlatch workdownlatch, intthreadindex,intstartIndex,intEndIndex) {         this. url =url;  this. FilePath =filePath;  this. Msgdownlatch =msgdownlatch;  this. Workdownlatch =workdownlatch;  this. Threadindex =threadindex;  this. StartIndex =startIndex;  this. EndIndex =endIndex; } @Override public voidRun () {Try {                //block this thread, waiting for the main thread to give the startup message (msgdownlatch.countdown ());msgdownlatch.await (); //Specific WorkLogger.info ("thread {} Task start", threadindex); URL URLPath=NewURL (url); HttpURLConnection Conn=(httpurlconnection) urlpath.openconnection (); Conn.setconnecttimeout (5000); Conn.setrequestproperty ("Range", "bytes=" + startIndex + "-" +endIndex); Conn.setrequestmethod ("GET"); intStatus =Conn.getresponsecode (); Logger.debug ("thread {} Request returned responsecode:{}", threadindex,status); if(status==206) {inputstream in=Conn.getinputstream (); Randomaccessfile RAF=NewRandomaccessfile (filePath, "rwd");                                        Raf.seek (startIndex); byte[] buffer =New byte[2048]; intLength = 0; Logger.debug ("thread {} start writing data, start point {}", threadindex,startindex);  while(length = In.read (buffer))! =-1){                        //logger.debug ("thread {} read size: {}", threadindex,length);Raf.write (buffer, 0, length); //Downloadlength + = length;} raf.close ();                In.close (); }Else{logger.error ("file Download failed, Status code:" +status); Throw NewException ("file Download failed, status code:" +status); } logger.info ("thread {} Task complete", threadindex); //work doneWorkdownlatch.countdown (); } Catch(throwable e) {logger.error (e.getmessage (), e);            E.printstacktrace (); }    }}

Mulitthreaddownload.java

Don't see what the problem, first write it down!

Java multi-threaded file download