第一个比较傻的做法 public static void main(String[] args) { // TODO Auto-generated method stub Scanner sc = new Scanner(System.in); // String string = sc.next(); String string = "abcd12345ed125ss123058789"; int start = 0; int end = 0; int length = 0; int maxLegth = 0; int maxStart = 0; int maxEnd = 0; boolean last = false; for (int i = 0; i < string.length(); i++) { char c = string.charAt(i); if ((c >= '0' && c <= '9')) {// 当前是数字 length++; if (last) {// 如果上一个也是数字 长度+1 if (i == string.length() - 1) { if (length >= maxLegth) { maxStart = start; maxEnd = string.length(); maxLegth = length; } } } else {// 如果不是 last = true; start = i; } } else { if (last) { if (length >= maxLegth) { maxStart = start; maxEnd = i; maxLegth = length; } } last = false; start = 0; end = 0; length = 0; } } if (maxLegth == 0) { System.out.println(0); } else { System.out.println(string.substring(maxStart, maxEnd)); System.out.println(maxLegth); } }