ツールクラス:文字列の数字列を抽出します(隣接する数字はそれぞれ開いています)

/**
 * @author Atimynyc
 * @version 1.0
 * @title        
 * @since 2019/1/30
 */
public class StringUtils {

    //        
    public static List getFullNumFromString(String str){
        List resultList = new ArrayList<>();
        StringBuilder numBuilder = new StringBuilder();
        str = str.replaceAll(" ","");
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (ch >= 48 && ch <= 57) {
                numBuilder.append(ch);
                if ( i == str.length() -1) {
                    resultList.add(numBuilder.toString());
                }
            } else {
                if (!numBuilder.toString().equals("") && numBuilder.length() > 0) {
                    resultList.add(numBuilder.toString());
                    numBuilder = new StringBuilder();
                }
            }
        }
        return resultList;
    }
}

List resultList = StringUtils.getFullNumFromString("500000>=[@amount@]>200000");