File Transfer-Error

[Roshini Sridharan]

Problem in File Read/Write using DatagramSocket/Packet.
How to use Datagram Socket to transmit binary data. Following contains a piece of code that i use to transmit text data and the code works fine for (textual data) and doesn't work fine for (.zip/.jpg) file format.
-----------------------------------------------------------
Client Code
FileOutputStream fos = new FileOutputStream(".\\temp\\"+filename,false);
boolean read = true;
int loop = 1;
DatagramPacket dp =null;
while(read)
{
byte buffer[] = new byte[size];
dp = new DatagramPacket(buffer,0,buffer.length);
System.out.println("Inside Receive " + loop);
Thread.sleep(10);
ds.receive(dp);
String str = new String(dp.getData());
buffer = str.getBytes();
int len = dp.getLength();
int offset = dp.getOffset();
System.out.println("Size " + len + "\tOffset " + offset);
fos.write(buffer, offset, len);
fos.flush();
if(len<size){
read = false; break;
}
loop++;
}
fos.close();
-----------------------------------------------------------
Server Code
for(int i =1;i<=loop;i++)
{
byte buffer[] = new byte[size];
int read = fis.read(buffer,0,buffer.length);
System.out.println(i + " Read : " + read + " B " + buffer.length);
dp = new DatagramPacket(buffer,0,read,InetAddress.getByName(clientip),clientport);
int offset = dp.getOffset();
int len = dp.getLength();
System.out.println("Size " + len + "\tOffset " + offset);
dp.setLength(len);
ds.send(dp);
Thread.sleep(50);
}
-----------------------------------------------------------
Can anybody suggest, how to change the code to support both ascii and binary data read/write.

Thanx in Advance
Regards
S.Roshini

[Ernest Friedman-Hill]

Well, it's these two lines:

 String str = new String(dp.getData());
 buffer = str.getBytes();

that are going to corrupt binary data when it's received. Many raw byte values will have special meanings when interpreted as characters -- 0 is going to be especially troublesome.
Replace these two lines with a simple "buffer = dp.getData()", and you should be in reasonable shape.

[Roshini Sridharan]

Hello Sir,
Thanx a lot for ur timely and valuable reply.
I got it working fine.
Regards
Roshini.S