判断email格式正确与否

public static boolean isEmail (String input) {
        if(input == null){
            return false;
        }
        String regEx = "([//w[_-][//.]]+@+[//w[_-]]+//.+[A-Za-z]{2,3})|([//"
            + "w[_-][//.]]+@+[//w[_-]]+//.+[//w[_-]]+//.+[A-Za-z]{2,3})|"
            + "([//w[_-][//.]]+@+[//w[_-]]+//.+[//w[_-]]+//.+[//w[_-]]+"
            + "//.+[A-Za-z]{2,3})";
        Pattern p = Pattern.compile(regEx);
        Matcher matcher = p.matcher(input);
        return matcher.matches();
    }