eg_2

2. 编写一个程序，输出在一个字符串中，指定的字符串出现的次数

第一种方法：

public class Test {
	public static void main(String[] args) {
		String s = "sunjava786$$%^*()Javajsdgkjavakh457-=javaqw213%%!!";
		String s0 = "java";
		int count = 0;
		int index = -1;
		while((index = s.indexOf(s0))!=-1){
			s = s.substring(index + s0.length());
			count++;
		}
		System.out.println("count: "+count);
	}
}// count: 3

 第二种方法：

public class Test {
	public static void main(String[] args) {
		String ss = "sunjava786$$%^*()Javajsdgkjavakh457-=javaqw213%%!!";
		String s0 = "java";
		int count = 0;
		int index = 0;
		int startPos = 0;
		while(index != -1){
			index = ss.indexOf(s0,startPos);
			startPos = index + s0.length(); // 或者 index = ss.indexOf(s0,index + s0.length())
			if(index != -1){
				count = count + 1;
			}
		}
		System.out.println("count:"+count);
	}
}// 3