https://www.tutorialspoint.com/Check-if-a-string-contains-a-number-using-Java

關鍵字：find number in string java
↑以上方法即可

提供一個正則表達式的寫法

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.ArrayList;

public class HelloWorld{

     public static void main(String []args){
        ArrayList<Integer> a = new ArrayList<Integer>();
        String REGEX = "[0-9]{1,}";
        String INPUT ="342jdfjls455m;lm;d03";
        
        Pattern p = Pattern.compile(REGEX);
        Matcher m = p.matcher(INPUT);
        
        while(m.find()){
            String digitstr = INPUT.substring(m.start(),m.end());
            a.add(Integer.parseInt(digitstr));
        }
        
        System.out.print(a);
     }
}