大小写字母,数字,特殊字符中的至少3种.8位以上,正确返回tru

public static boolean rexCheckPassword(String input) {
        // 8-20 位，字母、数字、字符
        String regStr = "^(?![a-zA-Z]+$)(?![A-Z0-9]+$)(?![A-Z\\W_]+$)(?![a-z0-9]+$)(?![a-z\\W_]+$)(?![0-9\\W_]+$)[a-zA-Z0-9\\W_]{8,20}$";
        return input.matches(regStr);
}

    @Test
public static void main(String[] args){
        System.out.println(rexCheckPassword("abcd"));
        System.out.println(rexCheckPassword("abcd1234"));
        System.out.println(rexCheckPassword("abcd1234#"));
        System.out.println(rexCheckPassword("Abcd1234"));
        System.out.println(rexCheckPassword("Abcd#$%"));
}}