求一個字符串的最大連續遞增數子串

public class FindLongestAccend {

	String findLongestAccendSubString(String src){
		if(src==null) return null;
		int len = src.length();
		if(len<=1) return src;
		int longest = 0;		
		String ret = "";
		int p1 = 0;
		while(p1<len){
			if(p1+1<len&&src.charAt(p1)+1==src.charAt(p1+1)){
				int count = 2;
				int p2 = p1+1;
				while(p2+1<len&&src.charAt(p2)+1==src.charAt(p2+1)){
					count++;
					p2++;
				}
				if(count > longest){
					longest = count;
					ret = src.substring(p1,p2+1);
					System.out.println(ret);
					p1 = p2;
				}
			}else {
				int count = 1;
				if(count > longest){
					longest = count;
					ret = String.valueOf(src.charAt(p1));
					System.out.println(ret);
				}
				p1++;
			}
		}
		return ret;
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		System.out.println(new FindLongestAccend().findLongestAccendSubString("abcdebcdefghi123456789"));
	}
}