如何在字符串Java中查找特定数字

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

public class Main {
    public static void main(String[] args) {
        String str = "abc 123 def 456 ghi";
        String pattern = "\\d+"; // 匹配一个或多个数字

        Pattern p = Pattern.compile(pattern);
        Matcher m = p.matcher(str);

        while (m.find()) {
            System.out.println(m.group()); // 打印匹配到的数字
        }
    }
}

public class Main {
    public static void main(String[] args) {
        String str = "abc 123 def 456 ghi";

        for (int i = 0; i < str.length(); i++) {
            if (Character.isDigit(str.charAt(i))) {
                System.out.println(str.charAt(i)); // 打印数字字符
            }
        }
    }
}