internet file size?

[Marco Schmidt]

Disintegration:

Is there a way to know a file size through a java internet program? Such as
first reading the size of an image over the internet on a web page given
that image link.

Some webservers return a content-length HTTP header. But you can't
count on it being there.

Regards,
Marco

 

[Disintegration]

Is there a way to know a file size through a java internet program? Such as
first reading the size of an image over the internet on a web page given
that image link.

thanks
ray

 

[Jon A. Cruz]

Is there a way to know a file size through a java internet program? Such as
first reading the size of an image over the internet on a web page given
that image link.

You mean "over HTTP"?

Nope.

Servers are supposed to send the size in the header, but for 1.0 that
was purely advisory (aka "don't count on this being real").

However...

If you have a nice, well behaved server, you could send it an HTTP HEAD
request to see what it wants to tell you the size is. It's not 'know'
with the certancy of java.io.File.length(), but is usable as long as you
don't trust it 100% (i.e. don't statically allocate an array to that
size and trust you can shove in without checking)

 

[Miguel De Anda]

Is there a way to know a file size through a java internet program? Such as
first reading the size of an image over the internet on a web page given
that image link.

thanks
ray

I guess you can have the java program download the image then see how big it
was.

 

[Jon A. Cruz]

int length = con.getContentLength();
System.out.println("Image file size is " + length + " bytes");
}
}

You could fine tune this by opening a socket directly, issuing an HTTP
HEAD command, then scanning the response headers for
"Content-Length:".

Remember, especially for HTTP 1.0, that this lenght could be only "advisory"

 

[Roedy Green]

If you want to know the width and height, you can read the first few
bytes and use some logic such is in the ImageInfo class.

See http://mindprod.com/products.html#BUS