ByteArrayOutputStream from OutputStream

Question

How to create OutputStream from ByteArrayOutputStream in Java

From your comments, you appear to want to create a ByteArrayOutputStream from a OutputStream. "I get OutputStream" and "This is reverse!" Is that what you really mean? — Peter Lawrey, May 04 '11 at 07:30

score 6 · Accepted Answer · answered May 04 '11 at 04:45

6

Following runs without error:

ByteArrayOutputStream stream = new ByteArrayOutputStream();
OutputStream outStream = stream;

If you see the docs for ByteArrayOutputStream you will find that it extends OutputStream.

answered May 04 '11 at 04:45

Harry Joy

1

The cast to `OutputStream` is unnecessary. – WhiteFang34 May 04 '11 at 04:47
@WhiteFang34: I was just removing that. – Harry Joy May 04 '11 at 04:48
you don't even need the intermediate stream variable. `OutputStream outStream = new ByteArrayOutputStream();` – рüффп Jul 09 '22 at 00:17

score 4 · Answer 2 · edited Jul 23 '12 at 13:51

4

ByteArrayOutputStream is a subclass of OutputStream.

ByteArrayOutputStream bos = ...;
OutputStream os = bos;

edited Jul 23 '12 at 13:51

Oak Bytes

answered May 04 '11 at 04:45

Im getting class cast exception in android when I do this :D – Taranfx May 04 '11 at 05:40
You shouldn't be. In fact assume you have control of the object, you should be doing OutputStream os=new ByteArrayOutputStream() to begin with.... – MJB May 04 '11 at 05:56
I get OutputStream from a ContentProvider, its not actually in my control. – Taranfx May 04 '11 at 06:31
@taranfx There will only be a ClassCastException if a cast is done. There is no cast in my example code. As MJB says, there is likely no need to deal with a ByteArrayOutputStream type directly as OutputStream contains all the relevant nominative type information. – May 05 '11 at 00:38

score 2 · Answer 3 · answered May 04 '11 at 04:44

2

A ByteArrayOutputStream is an OutputStream. I.e. you can just assign it like this:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
OutputStream out = baos;

answered May 04 '11 at 04:44

WhiteFang34

Reverse? What are you talking about? – WhiteFang34 May 04 '11 at 06:35
1

I imagine that he wants a BAOS from an OutputStream ( which has been obtained from something like HttpUrlConnection.getOutputStream() ) which is also the situation i am in! – Dori Jun 24 '11 at 09:54

score -3 · Answer 4 · answered May 05 '11 at 14:17

-3

You can create a helper method like follows:

public OutputStream convert(ByteArrayOutputStream arrayOutputStreamParam){
        return arrayOutputStreamParam;
    }

answered May 05 '11 at 14:17

Koekiebox

It's useless as the ByteArrayOutputStream is an implementation of the OutputStream Interface, see the accepted answer. – рüффп Jul 09 '22 at 00:19

4 Answers4