Add function to calculate SHA-256 has sum to StingUtils.

src/main/java/com/gitblit/utils/StringUtils.java

@@ -336,6 +336,28 @@ public class StringUtils {
 	{
 		return getDigest(bytes, "SHA-1");
 	}
+
+
+	/**
+	 * Calculates the SHA256 of the string.
+	 *
+	 * @param text
+	 * @return sha256 of the string
+	 */
+	public static String getSHA256(String text)
+	{
+		return getDigest(text, "SHA-256");
+	}
+
+	/**
+	 * Calculates the SHA256 of the byte array.
+	 *
+	 * @param bytes
+	 * @return sha256 of the byte array
+	 */
+	public static String getSHA256(byte[] bytes)
+	{
+		return getDigest(bytes, "SHA-256");
 	}
 
 	/**

src/test/java/com/gitblit/tests/StringUtilsTest.java

@@ -133,6 +133,12 @@ public class StringUtilsTest extends GitblitUnitTest {
 				StringUtils.getSHA1("blob 16\000what is up, doc?"));
 	}
 
+	@Test
+	public void testSHA256() throws Exception {
+		assertEquals("badf72532e259f2b67a40475486c7e71bf48bc71d7b0d43d8e99acfb3ac24e1b",
+					 StringUtils.getSHA256("margaret@london.uk"));
+	}
+
 	@Test
 	public void testMD5() throws Exception {
 		assertEquals("77fb8d95331f0d557472f6776d3aedf6",