正則表達式的理解

正則表達式;
1.徹底匹配,直接輸入字母數字
2.. 佔位通配
3.多箇中的的任意一個[" "]







import java.util.Scanner;

public class RegularExpression {

    public static void main(String[] args) {
        
        System.out.print("請輸入:");
        Scanner scanner =new Scanner(System.in);
        String []q={scanner.next()};
        regular(q);
    }
    public static void regular(String []q){
        if(q.length>0){
            for (String x:q){
                if(x.matches("[0-9]")){            
                    System.out.println("is ok");
                }else{
                    System.out.println("is NG");
                }
            }
        }else{
            System.out.println(" no data"); }
    }
    }