Question

Can we convert a byte array into an InputStream in Java? I have been looking on the internet but couldn t find it.

I have a method that has an InputStream as argument.

The InputStream cph I have is base64 encoded so I had to decode it using

BASE64Decoder decoder = new BASE64Decoder();
byte[] decodedBytes = decoder.decodeBuffer(cph);

Now how do I convert decodedBytes again to InputStream?

Answer 1

Use ByteArrayInputStream:

InputStream is = new ByteArrayInputStream(decodedBytes);

Answer 2

java.io.ByteArrayInputStream extends InputStream to do exactly this:

InputStream myInputStream = new ByteArrayInputStream(myBytes);

Answer 3

It is in the javadocs:

byte[] byteArr = new byte[] { 0xC, 0xA, 0xF, 0xE };
InputStream is = new ByteArrayInputStream(byteArr);

Answer 4

If you use Robert Harder s Base64 utility, then you can do:

InputStream is = new Base64.InputStream(cph);

Or with sun s JRE, you can do:

InputStream is = new
com.sun.xml.internal.messaging.saaj.packaging.mime.util.BASE64DecoderStream(cph)

However don t rely on that class continuing to be a part of the JRE, or even continuing to do what it seems to do today. Sun say not to use it.

There are other Stack Overflow questions about Base64 decoding, such as this one.

Answer 5

Its possible to convert byte[] to InputStream using Guava library as well.

     <dependency>
        <groupId>com.google.guava</groupId>
        <artifactId>guava</artifactId>
        <version>19.0</version>
    </dependency>



    public static void guavaConversion() throws IOException{
       byte[] bytesArray = {1, 2, 3};
       InputStream inputStream = ByteSource.wrap(bytesArray).openStream();

       System.out.println(inputStream.toString().getBytes().length); //just 
       //for testing
       inputStream.close();
    }

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