public static void main(String[] args) {

            String s1 = "adcdcjncdfbcdcdcd";

            String s2 = "cd";

            count(s1, s2);

        }

        public static void count(String str1, String str2) {

            int count = 0;

            if (str1.equals("") || str2.equals("")) {

                System.out.println("你没有输入字符串或子串，无法比较！");

                //System.exit(0);

            } else {

                for (int i = 0; i <= str1.length() - str2.length(); i++) {

                    if (str2.equals(str1.substring(i, str2.length() + i)))

                        count++;

                }

                System.out.println("子串" + str2 + "在字符串" + str1 + "中出现了: " + count

                        + " 次。");

            }

        }