Java Byte Array to InputStream

1. Overview

In this quick tutorial we’re going to illustrate how to convert a simple byte[] to an InputStream, first using plain java and then the Guava library.

This article is part of the “Java – Back to Basic” series here on VietMX’s Blog.

2. Convert Using Java

First – let’s look at the Java solution:

@Test
public void givenUsingPlainJava_whenConvertingByteArrayToInputStream_thenCorrect() 
  throws IOException {
    byte[] initialArray = { 0, 1, 2 };
    InputStream targetStream = new ByteArrayInputStream(initialArray);
}

3. Convert Using Guava

Next – let’s use wrap the byte array into the Guava ByteSource – which then allows us to get the stream:

@Test
public void givenUsingGuava_whenConvertingByteArrayToInputStream_thenCorrect() 
  throws IOException {
    byte[] initialArray = { 0, 1, 2 };
    InputStream targetStream = ByteSource.wrap(initialArray).openStream();
}

And there you have it – a simple way of opening an InputStream from a byte array.