Difference between String.getBytes() and IOUtils.toByteArray()?

java junit bytearray apache-commons
Falci picture Falci · Nov 23, 2012 · Viewed 14.1k times · Source

I'm testing the IOUtils. I have problems to convert an InputStream into a byte array:

private static final String LOREM_IPSUM = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";

@Test
public void testInputStreamToByteArray() throws IOException {

    byte[] expecteds = LOREM_IPSUM.getBytes();
    byte[] actuals = org.apache.commons.io.IOUtils.toByteArray(new StringInputStream(LOREM_IPSUM));

    assertArrayEquals(expecteds, actuals);
}

Stacktrace:

java.lang.AssertionError: array lengths differed, expected.length=56 actual.length=112
    at org.junit.Assert.fail(Assert.java:91)
    at org.junit.internal.ComparisonCriteria.assertArraysAreSameLength(ComparisonCriteria.java:72)
    at org.junit.internal.ComparisonCriteria.arrayEquals(ComparisonCriteria.java:36)
    at org.junit.Assert.internalArrayEquals(Assert.java:414)
    at org.junit.Assert.assertArrayEquals(Assert.java:200)
    at org.junit.Assert.assertArrayEquals(Assert.java:213)
    at [...].testInputStreamToByteArray(HttpsTest.java:20)[...]

I do not see why not pass the test. What is wrong?

Answer

Phil K picture Phil K · Nov 23, 2012

Specifying the encoding is important.

You haven't provided any encoding for the libraries to work with, and as a result the "default" encoding will be used instead. I'm guessing that since one of your byte arrays is twice the size of the other, one encoding used is UTF-16 and the other UTF-8/ASCII.

Try this:

public void testInputStreamToByteArray() throws IOException {

    byte[] expecteds = LOREM_IPSUM.getBytes("UTF-8");
    byte[] actuals = org.apache.commons.io.IOUtils.toByteArray(new StringReader(LOREM_IPSUM), "UTF-8");

    assertArrayEquals(expecteds, actuals);
}

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