[Java] UUIDをBase64に変換 (URLSafe)

UUIDBase64URLSafeTest.java

public class UUIDBase64URLSafeTest {

  String toBase64Url(UUID uuid) {
    return toBase64Url(uuid.getMostSignificantBits())
        + toBase64Url(uuid.getLeastSignificantBits());
  }

  String toBase64Url(long src) {
    byte[] binaryData = toBinaryData(src);
    return Base64.encodeBase64URLSafeString(binaryData);
  }

  private byte[] toBinaryData(long src) {
    final int longBits = 64, byteBits = 8;
    final int dataBytes = longBits / byteBits;
    byte[] res = new byte[dataBytes];
    for (int i = 0; i < dataBytes; i++) {
      res[i] = (byte) (src >>> byteBits * (dataBytes - i - 1));
    }
    return res;
  }

  @Test
  public void testToBase64UrlLong() {
    assertEquals(StringUtils.repeat('A', 11), toBase64Url(0L));
    assertEquals("AAAAAAAAAAE", toBase64Url(1L));
    assertEquals("AAAAAAAAAD8", toBase64Url(63L));
    assertEquals("AAAAAAAAAEA", toBase64Url(64L));
    assertEquals("f_________8", toBase64Url(Long.MAX_VALUE));
    assertEquals("__________8", toBase64Url(-1L));
    assertEquals("gAAAAAAAAAA", toBase64Url(Long.MIN_VALUE));
  }

  @Test
  public void testToBase64Url() {
    String res = toBase64Url(new UUID(1L, 2L));
    assertEquals("AAAAAAAAAAEAAAAAAAAAAI", res);
  }

  @Test
  public void testToBase64UrlRandom() {
    String res = toBase64Url(UUID.randomUUID());
    assertTrue(res, res.matches("[a-zA-Z0-9_-]{22}"));
  }
}