public class Demo3{
     public static void main(String [] args){
            int num = 0;
		int t = 0;
		Scanner sc = new Scanner(System.in);
		System.out.println("請輸入一個字符串:");
		//存儲鍵盤錄入的字符串
		String n = sc.next();
		System.out.println("請輸入需要查找的字符:");
		String s = sc.next();
		String [] Str = n.split(s);
		System.out.println(Str.length-1);
    }
}        

public class Demo3 {

	public static void main(String[] args) {
                 int num = 0;
		int t = 0;
		Scanner sc = new Scanner(System.in);
		System.out.println("請輸入一個字符串:");
		//存儲鍵盤錄入的字符串
		String n = sc.next();
		System.out.println("請輸入需要查找的字符:");
		String s = sc.next();
		for(int i=0;i<n.length();i++){
			 t = n.indexOf(s,i);
			if(t!=-1){
				num++;
				i=t;
			}
		}	
		System.out.println(num);
    }
}                

.從鍵盤錄入一個字符串並統計指定字符串出現的次數