字符串匹配算法--BF算法

class BF
{
String total_string;
String sub_string;
public BF(String a,String b)
{
total_string=a;
sub_string=b;

}
public int find()
{
int i;
for(i=0;i<=total_string.length()-sub_string.length();i++)
{
int j=0;
int q=i;
while(total_string.substring(q,q+1).equals(sub_string.substring(j,j+1)))
{
j++;
q++;
if(j==sub_string.length()-1)
return i;
}
}
return -1;
}
public static void main(String[] args)
{
BF b=new BF("ABCDEF","DEF");
System.out.println(b.find());
}
}