public class Main { public static void main(String[] args) { System.out.println(decode("a2bc10d1")); } public static String decode(String str){ if (str==null||str.length()==0) { return null; } String[] strstr = str.split("\\d+"); String[] strnum = str.split("[a-zA-Z]+"); StringBuilder stringBuilder = new StringBuilder(); int i=0;//统计strstr int j=0;//统计strnum while (i<strstr.length&&j<strnum.length) { if (strnum[j]!=null&&!strnum[j].equals("")) { int num = Integer.parseInt(strnum[j]); for (int k = 0; k < num; k++) { stringBuilder.append(strstr[i]); } i++; } j++; } return new String(stringBuilder); } }