indexOf substring

如下所示：

 public static void main(String[] args)
    {        
        String url = "http://bbs.zqh.com/user/login.html";
        System.out.println(url);
        int a = url.indexOf("/")+2;
        String surl1 = url.substring(a,url.length());
        System.out.println(surl1);
        int b = surl1.indexOf("/");
        String surl2 = surl1.substring(0,b);
        System.out.println(surl2);
        int c =surl2.indexOf(".");
        String url3 = surl2.substring(c,b);
        System.out.println(url3);
    }

substring截取从0开始，截取的字符串理解为：str 大于等于起始，小于末尾。
下面是api的demo:

"hamburger".substring(4, 8) returns "urge"
 "smiles".substring(1, 5) returns "mile"