Easy way to write contents of a Java InputStream to an OutputStream

java io stream
Matt Sheppard picture Matt Sheppard · Sep 4, 2008 · Viewed 447.4k times · Source

I was surprised to find today that I couldn't track down any simple way to write the contents of an InputStream to an OutputStream in Java. Obviously, the byte buffer code isn't difficult to write, but I suspect I'm just missing something which would make my life easier (and the code clearer).

So, given an InputStream in and an OutputStream out, is there a simpler way to write the following?

byte[] buffer = new byte[1024];
int len = in.read(buffer);
while (len != -1) {
    out.write(buffer, 0, len);
    len = in.read(buffer);
}

Answer

Mikezx6r picture Mikezx6r · Sep 9, 2008

As WMR mentioned, org.apache.commons.io.IOUtils from Apache has a method called copy(InputStream,OutputStream) which does exactly what you're looking for.

So, you have:

InputStream in;
OutputStream out;
IOUtils.copy(in,out);
in.close();
out.close();

...in your code.

Is there a reason you're avoiding IOUtils?

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