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[] http://stackoverflow.com/questions/2163644/in-java-how-can-i-convert-an-inputstream-into-a-byte-array-byte http://stackoverflow.com/questions/1264709/convert-inputstream-to-byte-in-java — h3xStream, Aug 16 '10 at 18:22
What exactly are you doing with images where you wouldn't be using the `javax.imageio` classes? — Powerlord, Aug 16 '10 at 18:59
Uploading to Amazon S3... The Java library I'm using required ByteArrayInputStream for all non-string based data — user398371, Aug 17 '10 at 15:45

naikus · Accepted Answer · 2010-08-16T18:34:05.567

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());
       }
}

I was almost there! Thanks for the example tho. A true master of IO! — user398371, Aug 16 '10 at 18:35

score 16 · Answer 2 · answered Oct 17 '19 at 10:42

16

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 '19 at 10:42

Jaroslav

737
10
19

1

why `IOUtils.toByteArray(is)` instead of `is.readAllBytes()` ? – mathiasfk Feb 05 '20 at 19:01
1

@mathiasfk no specific reason, just force of habit (never tried the other) – Jaroslav Feb 06 '20 at 14:37

score 4 · Answer 3 · answered Nov 07 '12 at 12:55

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);

Convert InputStream(Image) to ByteArrayInputStream

3 Answers3

Linked