public static void main(String[] args) {
String regex="^(?!.*(abc)).*$";//用到了前瞻
System.out.println("cba123abcsfd".matches(regex));//false不通过
System.out.println("cba123abscsfd".matches(regex));//true通过
System.out.println("cba123abscabc".matches(regex));//fals不通过
System.out.println("abc123abscabc".matches(regex));//false不通过
}
^(abc)?