/**
 * 统计字符串中“-”的数量
 * @param str 要统计的字符
 * @return
 */
public int levelCount(String str){
    int count = 0;
    int start = 0;
    while (str.indexOf("-", start) >= 0 && start < str.length()) {
      count++;
      start = str.indexOf("-", start) + "-".length();
    }
    return count;
}