DataOutputStream how make wirte dev/null

[Rafal\(sxat\)]

Hi

How create DataOutputStream for writing all data to NULL because I have make
simulate write because I have calc Content-Length for make POST to server

Rf

 

[Mark Space]

How create DataOutputStream for writing all data to NULL because I have make
simulate write because I have calc Content-Length for make POST to server

I'm not sure exactly what you mean by "write to NULL" but if you just
need a sink for data, this will do:


package fubar;

import java.io.DataOutputStream;
import java.io.IOException;
import java.iutputStream;

public class WriteSink extends OutputStream {


@Override
public void write(int b) {
}

@Override
public void write(byte[] b) {
}

@Override
public void write(byte[] b, int offset, int len ) {
}

public static void main(String[] args) throws IOException {
DataOutputStream dos = new DataOutputStream( new WriteSink() );

System.out.println("Start write sink...");
final int WRITES = 1*1000*1000;
for( int i =0; i < WRITES; i++ ) {
dos.write( i );
}
dos.flush();
dos.close();
System.out.println("Done.");
}
}

 

[Rafal\(sxat\)]

}

dos.flush();
dos.close();
System.out.println("Done.");
}

very thanks!!

Rf

 

[John B. Matthews]

I'm not sure exactly what you mean by "write to NULL" but if you just
need a sink for data, this will do:

This is a good approach, as it may save a round trip through the
operating system [1, 2]. Saving the length looks like a straightforward
addition, although it seems like the data model should already know it:

package fubar;

import java.io.DataOutputStream;
import java.io.IOException;
import java.iutputStream;

public class WriteSink extends OutputStream {

private int contentLength;

public int getContentLength() {
return contentLength;
}

@Override
public void write(int b) {
contentLength++;
}
// etc.
}

[Not tested.]
[1]<http://mindprod.com/jgloss/discardingoutput.html>
[2]<http://groups.google.com/group/comp.lang.java.help/browse_frm/thread/
9bb9c81384afc634/bba6a7b626b2e932>

 

[Mark Space]

public class WriteSink extends OutputStream {

private int contentLength;

public int getContentLength() {
return contentLength;
}

While I didn't show it in my example, DataOutputStream implements a
"size()" method that returns the bytes written, up to Integer.MAX_VALUE,
so there's no need to re-invent the wheel here.

 

[Arne Vajhøj]

How create DataOutputStream for writing all data to NULL because I have make
simulate write because I have calc Content-Length for make POST to server

Don't.

Wrap DataOutputStream around a ByteArrayOutputStream, write your stuff,
find length and then write the created bytes when you need to do the
actual write.

Arne

 

[Roedy Green]

Hi

How create DataOutputStream for writing all data to NULL because I have make
simulate write because I have calc Content-Length for make POST to server

see http://mindprod.com/jgloss/discardingoutput.html
--
Roedy Green Canadian Mind Products
http://mindprod.com

Never discourage anyone... who continually makes progress, no matter how slow.
~ Plato 428 BC died: 348 BC at age: 80

 

[Kevin McMurtrie]

Hi

How create DataOutputStream for writing all data to NULL because I have make
simulate write because I have calc Content-Length for make POST to server

Rf

HTTP 1.1 chunked encoding is an excellent substitute for Content-Length.
It's simple to implement and it eliminates potentially severe
performance problems with the Content-Length header.