public static boolean isNumber(String value) {
        try {
            Double.parseDouble(value);
        } catch (NumberFormatException nfe) {
            return false;
        }
        return true;
    }
@Test
    public void testIsNumber() {
        Assert.assertTrue(StringKit.isNumber("20"));
        Assert.assertTrue(StringKit.isNumber("20.1"));
        Assert.assertFalse(StringKit.isNumber("abc"));
        Assert.assertFalse(StringKit.isNumber("21w"));
    }