StringUtils { public static String[] split(String src, String separator) { if (isEmpty(separator)) { return new String[] { src }; } if (isEmpty(src)) { return StringUtils.EMPTY_STRING_ARRAY; } return src.split(separator, -1); }  static boolean isEmpty(CharSequence cs); static boolean isNotEmpty(CharSequence cs); static boolean isBlank(CharSequence cs); static boolean isNotBlank(CharSequence cs); static String trim(String str); static String trimToNull(String str); static String trimToEmpty(String str); static String toString(byte[] bytes, String charsetName); static String defaultString(final Object str); static String toString(Object o, String defaultVal); static String toString(Object o); static String objectsToString(Object[] args); static boolean equals(CharSequence s1, CharSequence s2); static String[] split(String src, String separator); static String[] splitWithCommaOrSemicolon(String src); static String join(String[] strings, String separator); static String joinWithComma(String... strings); static String substringAfter(String str, String separator); static String substringBefore(String str, String separator); static final String EMPTY; static final String CONTEXT_SEP; static final String ALL; static final String DEFAULT; static final String TRUE; static final String FALSE; static final String NULL; static final String[] EMPTY_STRING_ARRAY; }
@Test public void testSplit() throws Exception { String[] array = StringUtils.split(null, ","); Assert.assertTrue(CommonUtils.isEmpty(array)); array = StringUtils.split("", ","); Assert.assertTrue(CommonUtils.isEmpty(array)); String src = "1;2;3"; array = StringUtils.split(src, null); Assert.assertTrue(array.length == 1); array = StringUtils.split(src, ","); Assert.assertTrue(array.length == 1); src = "1;2;3"; array = StringUtils.split(src, ";"); Assert.assertTrue(array.length == 3); Assert.assertArrayEquals(array, new String[] { "1", "2", "3" }); src = ";1;2;3;"; array = StringUtils.split(src, ";"); Assert.assertTrue(array.length == 5); Assert.assertArrayEquals(array, new String[] { "", "1", "2", "3", "" }); src = "; 1;2 ; 3 ;"; array = StringUtils.split(src, ";"); Assert.assertTrue(array.length == 5); Assert.assertArrayEquals(array, new String[] { "", " 1", "2 ", " 3 ", "" }); }