In this quick tutorial we’re going to take a look at converting an InputStream to a Reader using Java, then Guava and finally Apache Commons IO.
This article is part of the “Java – Back to Basic” series here on Baeldung.
1. With Java
First, let’s look at the simple Java solution – using the readily available InputStreamReader:
@Test
public void givenUsingPlainJava_whenConvertingInputStreamIntoReader_thenCorrect()
throws IOException {
InputStream initialStream = new ByteArrayInputStream("With Java".getBytes());
Reader targetReader = new InputStreamReader(initialStream);
targetReader.close();
}2. With Guava
Next – let’s take a look at the Guava solution – using an intermediary byte array and String:
@Test
public void givenUsingGuava_whenConvertingInputStreamIntoReader_thenCorrect()
throws IOException {
InputStream initialStream = ByteSource.wrap("With Guava".getBytes()).openStream();
byte[] buffer = ByteStreams.toByteArray(initialStream);
Reader targetReader = CharSource.wrap(new String(buffer)).openStream();
targetReader.close();
}Note that the Java solution is simpler than this approach.
3. With Commons IO
Finally – the solution using Apache Commons IO – also using an intermediary String:
@Test
public void givenUsingCommonsIO_whenConvertingInputStreamIntoReader_thenCorrect()
throws IOException {
InputStream initialStream = IOUtils.toInputStream("With Commons IO");
byte[] buffer = IOUtils.toByteArray(initialStream);
Reader targetReader = new CharSequenceReader(new String(buffer));
targetReader.close();
}And there you have it – 3 quick ways to convert the input stream to a Java Reader.
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