HTTP breakpoint download Client and server

Client
Import Java.io.BufferedInputStream;
Import Java.io.File;
Import Java.io.RandomAccessFile;
Import java.net.HttpURLConnection;
Import Java.net.URL;

public class Arcsynchttpclient {
public static void Main (string[] args) throws Exception {


String strURL = "Http://localhost:8080/ArcSyncHttpDownload/httpServlet";
URL downurl = new URL (strurl);
HttpURLConnection cn = (httpurlconnection) downurl.openconnection ();
if (cn.getresponsecode () = = 200) {
InputStream is = Cn.getinputstream ();
int part_count = 10;

int contentlength = Cn.getcontentlength ();
System.out.println ("Cn.getcontentlength ():" +cn.getcontentlength ());
int firstlength = Contentlength/part_count;
System.out.println ("Firstlength ():" + firstlength);
Cn.disconnect ();
Part_count = 1;
for (int i = 1; i < part_count+1; i++) {
if (I==part_count) {
int lastlength = contentlength-firstlength* (part_count-1);
File SaveFile = new file ("E:/test/123", String.Format ("123_0%d.mp3", I));
Testdownload.download (Savefile.getname (), Savefile.getparent (),
strURL, (i-1) *firstlength, contentlength);
}else {
File SaveFile = new file ("E:/test/123", String.Format ("123_0%d.mp3", I));
Testdownload.download (Savefile.getname (), Savefile.getparent (),
strURL, (i-1) *firstlength, firstlength*i);
}

}
}
}

public static void Download (string fileName, String filepath,string remoteurl, long start, long end) {
byte[] buf = new byte[10240];
HttpURLConnection httpurlconnection;
URL url;
Bufferedinputstream bis;
int size;
Randomaccessfile Rndfile;
Download file
try {
url = new URL (remoteurl);
HttpURLConnection = (httpurlconnection) url.openconnection ();
Set User-agent
Httpurlconnection.setrequestproperty ("User-agent", "Net");
Set Resume Start
Httpurlconnection.setrequestproperty ("Range", "bytes=" + Start + "-" + end);
Get input stream
bis = new Bufferedinputstream (Httpurlconnection.getinputstream ());
Rndfile = new Randomaccessfile (filePath + "\ \" + FileName, "RW");
Rndfile.seek (0);
int i = 0;
while (size = Bis.read (BUF))! =-1) {
if (i >) break;
Rndfile.write (buf, 0, size);

i++;
}
System.out.println ("i=" + i);
Httpurlconnection.disconnect ();
Bis.close ();
Rndfile.close ();
} catch (Exception e) {
Todo:handle exception
E.printstacktrace ();
}
}

public static long Getremotefileszie (String URL) {
Long size = 0;
try {
HttpURLConnection Httpurl = (httpurlconnection) (new URL (URL)). OpenConnection ();
Size = Httpurl.getcontentlength ();
Httpurl.disconnect ();
} catch (Exception e) {
Todo:handle exception
E.printstacktrace ();
}
return size;
}

public static void Mergefiles (String outFile, list<string> files) {
FileChannel outchannel = null;
System.out.println ("Merge" + Files + "into" + outFile);
try {
Outchannel = new FileOutputStream (outFile). Getchannel ();
for (String f:files) {
FileChannel fc = new FileInputStream (f). Getchannel ();
Bytebuffer BB = bytebuffer.allocate (BUFSIZE);
while (Fc.read (BB)! =-1) {
Bb.flip ();
Outchannel.write (BB);
Bb.clear ();
}
Fc.close ();
}
System.out.println ("merged!!");
} catch (IOException IoE) {
Ioe.printstacktrace ();
} finally {
try {
if (Outchannel! = null) {
Outchannel.close ();
}
} catch (IOException ignore) {
}
}
}

}

Service side

Package Com.defonds.cds.common;


Import Java.io.BufferedOutputStream;
Import Java.io.File;
Import java.io.IOException;
Import Java.io.OutputStream;
Import Java.io.RandomAccessFile;

Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;

HTTP Breakpoint Continuation Demo (Client Test tool: Express, Thunderbolt)
public class Arcsynchttpdownloadservlet extends HttpServlet {
Private static final long serialversionuid = 1L;
Final static log log = Logfactory.getlog (Arcsynchttpdownloadservlet.class);

@Override
protected void Doget (HttpServletRequest req, HttpServletResponse resp)
Throws Servletexception, IOException {
This.dopost (req, resp);
}

@Override
protected void DoPost (HttpServletRequest request, httpservletresponse response) {
File DownloadFile = new ("E:/test/123.mp3");//Files to download
Long filelength = Downloadfile.length ();//Record file size
System.out.println ("Filelength:" +filelength);
Long pastlength = 0;//record downloaded file size
int rangeswitch = 0;//0: full-text download from scratch; 1: Download starting from a byte (bytes=27000-); 2: Download from start of a byte to end of a byte (bytes=27000-39000)
Long tolength = 0;//records the last byte offset of the byte segment that the client needs to download (for example, bytes=27000-39000, this value is 39000)
Long ContentLength = 0;//The total number of bytes requested by the client
String rangebytes = "";//record the contents of the client's form such as "bytes=27000-" or "bytes=27000-39000"
Randomaccessfile RAF = null;//is responsible for reading the data
OutputStream OS = null;//Write Data
OutputStream out = null;//buffer
byte b[] = new byte[1024];//staging container

if (Request.getheader ("Range") = null) {//client requests the start byte of the downloaded file block
Response.setstatus (Javax.servlet.http.HttpServletResponse.SC_PARTIAL_CONTENT);
System.out.println ("Request.getheader (\" range\ ") =" + Request.getheader ("Range");
Rangebytes = Request.getheader ("Range"). ReplaceAll ("bytes=", "" ");
int index = rangebytes.indexof ('-');
int length = Rangebytes.length ()-1;
if (index = = 1) {//bytes=969998336-
Rangeswitch = 1;
rangebytes = rangebytes.substring (0, Rangebytes.indexof ('-'));
String temp0 = rangebytes.substring (0,rangebytes.indexof ('-'));
String Temp2 = rangebytes.substring (Rangebytes.indexof ('-') + 1, rangebytes.length ());
Pastlength = Long.parselong (Temp0.trim ());
if ("". Equals (Temp2)) {
ContentLength = filelength-pastlength + 1;//The client is requesting bytes after 969998336
}else {
Tolength = Long.parselong (TEMP2);//bytes=1275856879-1275877358, to the end of the 1,275,877,358th byte
ContentLength = tolength-pastlength + 1;//The client requested a byte between 1275856879-1275877358
}
} else {//bytes=1275856879-1275877358
Rangeswitch = 2;
String temp0 = rangebytes.substring (0,rangebytes.indexof ('-'));
String Temp2 = rangebytes.substring (Rangebytes.indexof ('-') + 1, rangebytes.length ());
Pastlength = Long.parselong (Temp0.trim ())//bytes=1275856879-1275877358, download starting from 1,275,856,879th byte
Tolength = Long.parselong (TEMP2);//bytes=1275856879-1275877358, to the end of the 1,275,877,358th byte
ContentLength = tolength-pastlength + 1;//The client requested a byte between 1275856879-1275877358
}
} else {//download from start
ContentLength = filelength;//Client requires full-text download
}

/**
* If Content-length is set, the client will automatically download multi-threaded. If you do not want to support multi-threading, do not set this parameter.
* The format of the response is:
* Content-length: [total file Size]-[Start byte of the downloaded file block of the client request]
* Servletactioncontext.getresponse (). SetHeader ("Content-length",
* New Long (File.length ()-P). toString ());
*/
Response.reset ();//tells the client to allow a breakpoint to continue multiple lines thread attached download, the format of the response is: accept-ranges:bytes
Response.setheader ("accept-ranges", "bytes");//If it is the first time, there is no continuation of the breakpoint, the state is the default of 200, no need to explicitly set; the format of the response is: http/1.1-OK
if (pastlength! = 0) {
Not downloaded from the very beginning,
The format of the response is:
content-range:bytes [The total size of the file block's start byte]-[file-The total size of the 1]/[file]
System.out.println ("----------------------------not download from the beginning! The server is about to start the breakpoint continues to pass ... ");
Switch (rangeswitch) {
Case 1: {//Request for bytes=27000-
String Contentrange = new StringBuffer ("bytes"). Append (New Long (pastlength). toString ()). Append ("-"). Append (New Long ( fileLength-1). ToString ()). Append ("/"). Append (new Long (Filelength). ToString ()). ToString ();
Response.setheader ("Content-range", Contentrange);
Break
}
Case 2: {//Request for bytes=27000-39000
String Contentrange = rangebytes + "/" + new Long (filelength). toString ();
Response.setheader ("Content-range", Contentrange);
Break
}
Default: {
Break
}
}
} else {
is from the beginning to download
System.out.println ("----------------------------is downloaded from the beginning! ");
}

try {
Response.AddHeader ("Content-disposition", "attachment; Filename=\ "" + downloadfile.getname () + "\" ");
Response.setcontenttype (Commonutil.setcontenttype (Downloadfile.getname ()));//Set the MIME type.
Response.AddHeader ("Content-length", String.valueof (ContentLength));
OS = Response.getoutputstream ();
out = new Bufferedoutputstream (OS);
RAF = new Randomaccessfile (DownloadFile, "R");
try {
Switch (rangeswitch) {
Case 0: {//normal download, or download from the beginning
Same 1
}
Case 1: {//Request for bytes=27000-
Raf.seek (pastlength);//A client request that is shaped like bytes=969998336-, skipping 969,998,336 bytes
int n = 0;
while ((n = raf.read (b, 0, 1024))! =-1) {
Out.write (b, 0, N);
}
Break
}
Case 2: {//Request for bytes=27000-39000
Raf.seek (pastLength-1);//A client request that is shaped like bytes=1275856879-1275877358, finds the 1,275,856,879th byte
int n = 0;
Long readlength = 0;//The number of read bytes recorded
while (Readlength <= contentLength-1024) {///most bytes read here
n = raf.read (b, 0, 1024);
Readlength + = 1024;
Out.write (b, 0, N);
}
if (readlength <= contentlength) {//The remaining less than 1024 bytes are read here
n = raf.read (b, 0, (int) (contentlength-readlength));
Out.write (b, 0, N);
}
//
Raf.seek (pastlength);//A client request that is shaped like bytes=1275856879-1275877358, finds the 1,275,856,879th byte
while (Raf.getfilepointer () < Tolength) {
Out.write (Raf.read ());
// }
Break
}
Default: {
Break
}
}
Out.flush ();
} catch (IOException IE) {
/**
* At the time of writing the data,
* For exceptions such as Clientabortexception,
* Because the client canceled the download, and the server continues to write data to the browser,
* Throw this exception, this is normal.
* Especially for thunder this blood-sucking client software,
* Obviously there is a thread reading the bytes=1275856879-1275877358,
* If not read in a short time, the Thunderbolt will restart the second, the third ... Threads to read the same byte segments,
* Until one thread has finished reading, the Thunderbolt will kill other threads that are downloading the same byte segment,
* Forcibly abort byte readout, causing the server to throw clientabortexception.
* So, we ignore this exception
*/
Ignore
}
} catch (Exception e) {
System.err.println (e);
} finally {
if (out! = null) {
try {
Out.close ();
} catch (IOException e) {
System.err.println (e);
}
}
if (RAF! = NULL) {
try {
Raf.close ();
} catch (IOException e) {
System.err.println (e);
}
}
}
}
}

Package Com.defonds.cds.common;
public class Commonutil {

public static string setContentType (String returnfilename) {
String ContentType = "Application/octet-stream";
if (Returnfilename.lastindexof (".") < 0)
return contentType;
Returnfilename = Returnfilename.tolowercase ();
Returnfilename = returnfilename.substring (returnfilename
. LastIndexOf (".") + 1);

if (returnfilename.equals ("html") | | | returnfilename.equals ("htm")
|| Returnfilename.equals ("shtml")) {
ContentType = "text/html";
} else if (Returnfilename.equals ("CSS")) {
ContentType = "Text/css";
} else if (returnfilename.equals ("xml")) {
ContentType = "Text/xml";
} else if (Returnfilename.equals ("gif")) {
ContentType = "Image/gif";
} else if (Returnfilename.equals ("JPEG")
|| Returnfilename.equals ("jpg")) {
ContentType = "Image/jpeg";
} else if (Returnfilename.equals ("JS")) {
ContentType = "Application/x-javascript";
} else if (Returnfilename.equals ("atom")) {
ContentType = "Application/atom+xml";
} else if (Returnfilename.equals ("RSS")) {
ContentType = "Application/rss+xml";
} else if (Returnfilename.equals ("MML")) {
ContentType = "Text/mathml";
} else if (returnfilename.equals ("TXT")) {
ContentType = "Text/plain";
} else if (Returnfilename.equals ("Jad")) {
ContentType = "Text/vnd.sun.j2me.app-descriptor";
} else if (Returnfilename.equals ("WML")) {
ContentType = "TEXT/VND.WAP.WML";
} else if (Returnfilename.equals ("HTC")) {
ContentType = "Text/x-component";
} else if (Returnfilename.equals ("png")) {
ContentType = "Image/png";
} else if (Returnfilename.equals ("TIF")
|| Returnfilename.equals ("TIFF")) {
ContentType = "Image/tiff";
} else if (Returnfilename.equals ("Wbmp")) {
ContentType = "Image/vnd.wap.wbmp";
} else if (Returnfilename.equals ("ico")) {
ContentType = "Image/x-icon";
} else if (Returnfilename.equals ("Jng")) {
ContentType = "Image/x-jng";
} else if (Returnfilename.equals ("BMP")) {
ContentType = "Image/x-ms-bmp";
} else if (Returnfilename.equals ("svg")) {
ContentType = "Image/svg+xml";
} else if (Returnfilename.equals ("Jar") | | | returnfilename.equals ("var")
|| Returnfilename.equals ("ear")) {
ContentType = "Application/java-archive";
} else if (Returnfilename.equals ("Doc")) {
ContentType = "Application/msword";
} else if (Returnfilename.equals ("PDF")) {
ContentType = "Application/pdf";
} else if (Returnfilename.equals ("RTF")) {
ContentType = "Application/rtf";
} else if (Returnfilename.equals ("xls")) {
ContentType = "application/vnd.ms-excel";
} else if (Returnfilename.equals ("ppt")) {
ContentType = "Application/vnd.ms-powerpoint";
} else if (Returnfilename.equals ("7z")) {
ContentType = "application/x-7z-compressed";
} else if (Returnfilename.equals ("rar")) {
ContentType = "application/x-rar-compressed";
} else if (Returnfilename.equals ("swf")) {
ContentType = "Application/x-shockwave-flash";
} else if (Returnfilename.equals ("RPM")) {
ContentType = "Application/x-redhat-package-manager";
} else if (Returnfilename.equals ("der") | | | returnfilename.equals ("PEM")
|| Returnfilename.equals ("CRT")) {
ContentType = "Application/x-x509-ca-cert";
} else if (Returnfilename.equals ("xhtml")) {
ContentType = "Application/xhtml+xml";
} else if (Returnfilename.equals ("Zip")) {
ContentType = "Application/zip";
} else if (Returnfilename.equals ("mid")
|| Returnfilename.equals ("MIDI")
|| Returnfilename.equals ("Kar")) {
ContentType = "Audio/midi";
} else if (Returnfilename.equals ("MP3")) {
ContentType = "Audio/mpeg";
} else if (Returnfilename.equals ("Ogg")) {
ContentType = "Audio/ogg";
} else if (Returnfilename.equals ("M4A")) {
ContentType = "AUDIO/X-M4A";
} else if (Returnfilename.equals ("RA")) {
ContentType = "Audio/x-realaudio";
} else if (Returnfilename.equals ("3GPP")
|| Returnfilename.equals ("3gp")) {
ContentType = "VIDEO/3GPP";
} else if (Returnfilename.equals ("mp4")) {
ContentType = "Video/mp4";
} else if (Returnfilename.equals ("MPEG")
|| Returnfilename.equals ("mpg")) {
ContentType = "Video/mpeg";
} else if (Returnfilename.equals ("mov")) {
ContentType = "Video/quicktime";
} else if (Returnfilename.equals ("flv")) {
ContentType = "video/x-flv";
} else if (Returnfilename.equals ("M4V")) {
ContentType = "VIDEO/X-M4V";
} else if (Returnfilename.equals ("MNG")) {
ContentType = "VIDEO/X-MNG";
} else if (Returnfilename.equals ("ASX") | | | returnfilename.equals ("ASF")) {
ContentType = "VIDEO/X-MS-ASF";
} else if (Returnfilename.equals ("wmv")) {
ContentType = "video/x-ms-wmv";
} else if (Returnfilename.equals ("avi")) {
ContentType = "Video/x-msvideo";
}

return contentType;
}
}

HTTP breakpoint download Client and server