子串问题

//需求：求子串在主串中第一次出现的位置问题

class  StringGetIndex
{

	public static int index(String str,String tes,int pos)
	{
		if(pos>0)
		{
			int n = str.length();
			int m = tes.length();
			int i = pos;

			while(i<=n-m+1)
			{
				String subString = str.substring(i,i+m);
				if(subString.compareTo(tes)==0)
				{
					return i;
				}
				else 
					i++;

			}
			
		}
		return 0;
	}
	public static void main(String[] args) 
	{
		String str = "fghijklmnoabcdeabcdepqrstuvwxyz";
		String tes = "abcde";
		int  pos=1;
		int i = index(str,tes,pos);
		System.out.println(str.length()+"  "+tes.length()+"\n"+i);
	}
}