public static boolean isEmpty(CharSequence cs) {
        return cs == null || cs.length() == 0;
    }
<p>Checks if a CharSequence is empty ("") or null.</p>
<pre>
StringUtils.isEmpty(null)      = true
StringUtils.isEmpty("")        = true
StringUtils.isEmpty(" ")       = false
StringUtils.isEmpty("bob")     = false
StringUtils.isEmpty("  bob  ") = false
</pre>

@param cs the CharSequence to check, may be null
@return {@code true} if the CharSequence is empty or null
pay-java-common/src/main/java/com/egzosn/pay/common/util/str/StringUtils.java