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Data over TCP/IP socket

Posted on 2004-07-30
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Last Modified: 2012-08-13
I'm looking out how to get data back and forth over TCP/IP.
I can see how to do char (see snippet below), but I don't know how to do other primitives (int, float) or how I would xfer an Object.
I guess I have to use something other than InputStreamReader/OutputStreamWriter.
What would I use?

InputStreamReader isr = null;
OutputStreamWriter osw = null;
isr = new InputStreamReader(socket.getInputStream());
osw = new OutputStreamWriter(socket.getOutputStream());

// read
char[] cbuf=null; // character buffer to get chars from stream
isr.read(cbuf,  0, 100);
valid = true;
string = cbuf.toString();

// write
osw.write(string, 0, string.length());
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Question by:omom
5 Comments
 
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Accepted Solution

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objects earned 50 total points
ID: 11682069
Use DataInputStream/DataOutputStream to handle passing various primitives.
ObjectInputStrea.ObjectOutputStream for passing objects.
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Expert Comment

by:JugglerW
ID: 11683235
ObjectInputStream and ObjectOutputStream are ok if you have Java on both sides of your communication line otherwise you have to do the marshalling yourself. e.g. to send a String you may use:

String toSend = "ABC";
OutputStream out;

byte[] bytes = toSend.getBytes();
out.write( out );

but you also must send the length of the string or null terminate or send a special delimiter character (which must be escaped if in contained in the string) to know it on the other side how many bytes to fetch from line.


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LVL 30

Expert Comment

by:Mayank S
ID: 11687618
If you use a buffered stream or writer, then make sure you also call flush (). BTW, don't use readers/ writers for primitives (you can use them for Strings). Stick to some InputStream/ OutputStream like suggested.
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Author Comment

by:omom
ID: 11728784
thanks for responses
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LVL 92

Expert Comment

by:objects
ID: 11731404
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