6-20位字符；数字、字母、特殊字符（除空格），起码其中两种组合

- (NSString *)checkPassWord1:(NSString *)passWord1 WithPassWord2:(NSString *)passWord2 WithUsername:(NSString *)uesrname {
    if ([passWord1 isEqualToString:passWord2]) {
        NSRange range = [passWord1 rangeOfString:@" "];
        if (range.location != NSNotFound) {
            return @"不能有空格";
        }else {
            if (passWord1.length >=6 && passWord1.length <=20) {
                NSString *passWordRegex = @"^(?=.*[a-zA-Z0-9].*)(?=.*[a-zA-Z\\W].*)(?=.*[0-9\\W].*).{8,20}$";//至少使用两种字符组合
                NSPredicate *pred = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", passWordRegex];
                if ([pred evaluateWithObject:passWord1]) {
                    if ([passWord1 isEqualToString:uesrname]) {
                        return @"密码与用户名相同，有被盗风险" ;
                    }else {
                        return @"";
                    }
                }else {
                    return @"至少使用两种字符组合";
                }
            } else {
                return @"长度只能在8-20个字符之间";
            }
        }
    } else {
        return @"两次输入密码不一致，请重新输入";
    }
}