Convert InputStream(Image) to ByteArrayInputStream

Question

Not sure about how I am supposed to do this. Any help would be appreciated

Since ByteArrayInputStream are construct from byte[] stackoverflow.com/questions/2163644/… stackoverflow.com/questions/1264709/… — h3xStream
– h3xStream, Commented Aug 16, 2010 at 18:22
What exactly are you doing with images where you wouldn't be using the javax.imageio classes? — Powerlord
– Powerlord, Commented Aug 16, 2010 at 18:59
Uploading to Amazon S3... The Java library I'm using required ByteArrayInputStream for all non-string based data — user398371
– user398371, Commented Aug 17, 2010 at 15:45

naikus · Accepted Answer · 2010-08-16 18:34:05Z

31

Read from input stream and write to a ByteArrayOutputStream, then call its toByteArray() to obtain the byte array.

Create a ByteArrayInputStream around the byte array to read from it.

Here's a quick test:

import java.io.*;

public class Test {


       public static void main(String[] arg) throws Throwable {
          File f = new File(arg[0]);
          InputStream in = new FileInputStream(f);

          byte[] buff = new byte[8000];

          int bytesRead = 0;

          ByteArrayOutputStream bao = new ByteArrayOutputStream();

          while((bytesRead = in.read(buff)) != -1) {
             bao.write(buff, 0, bytesRead);
          }

          byte[] data = bao.toByteArray();

          ByteArrayInputStream bin = new ByteArrayInputStream(data);
          System.out.println(bin.available());
       }
}

edited Aug 16, 2010 at 18:34

answered Aug 16, 2010 at 18:17

naikus

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2 Comments

user398371 Over a year ago

I was almost there! Thanks for the example tho. A true master of IO!

F.O.O Over a year ago

large buffer size though

Jaroslav · Accepted Answer · 2019-10-17 10:42:30Z

19

You can use org.apache.commons.io.IOUtils#toByteArray(java.io.InputStream)

InputStream is = getMyInputStream();
ByteArrayInputStream bais = new ByteArrayInputStream(IOUtils.toByteArray(is));

answered Oct 17, 2019 at 10:42

Jaroslav

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3 Comments

mathiasfk Over a year ago

why IOUtils.toByteArray(is) instead of is.readAllBytes() ?

Jaroslav Over a year ago

@mathiasfk no specific reason, just force of habit (never tried the other)

Jaroslav Over a year ago

EDIT: because it is available only since Java 9, and I was using 7 / 8 (tutorialspoint.com/… )

anvarik · Accepted Answer · 2012-11-07 12:55:54Z

4

Or first convert it to a byte array, then to a bytearrayinputstream.

File f = new File(arg[0]);
InputStream in = new FileInputStream(f);
// convert the inpustream to a byte array
byte[] buf = null;
try {
    buf = new byte[in.available()];
    while (in.read(buf) != -1) {
    }
} catch (Exception e) {
    System.out.println("Got exception while is -> bytearr conversion: " + e);
}
// now convert it to a bytearrayinputstream
ByteArrayInputStream bin = new ByteArrayInputStream(buf);

answered Nov 7, 2012 at 12:55

anvarik

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Comments

Cleverson Sacramento · Accepted Answer · 2023-05-27 14:42:30Z

0

Using Kotlin and org.apache.commons.io.IOUtils v2 is simple like that:

IOUtils.toByteArray(is).inputStream()

I guess is the same way in Java too.

answered May 27, 2023 at 14:42

Cleverson Sacramento

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