public static String getClusterName(final String originalFilename) {
    checkThreePart(originalFilename);
    return getThreePart(originalFilename)[1];
  }
@Test
  public void getClusterName() {
    final String cluster = ConfigFileUtils.getClusterName("application+default+application.properties");
    assertEquals("default", cluster);

    final String Beijing = ConfigFileUtils.getClusterName("abc+Beijing+application.yml");
    assertEquals("Beijing", Beijing);
  }