public static String join(String[] array) {
        if (ArrayUtils.isEmpty(array)) {
            return EMPTY_STRING;
        }
        StringBuilder sb = new StringBuilder();
        for (String s : array) {
            sb.append(s);
        }
        return sb.toString();
    }
@Test
    void testJoinCollectionString() throws Exception {
        List<String> list = new ArrayList<String>();
        assertEquals("", StringUtils.join(list, ","));

        list.add("v1");
        assertEquals("v1", StringUtils.join(list, "-"));

        list.add("v2");
        list.add("v3");
        String out = StringUtils.join(list, ":");
        assertEquals("v1:v2:v3", out);
    }