Getting SharePoint objects (spweb, splist, splistitem) from url string

You basically get anything in the object model with one full url:

 //here is the site for the url
 using (SPSite site = new SPSite("http://basesmcdev2/sites/tester1/tester4/A0805051340564172608.txt"))
 {
        //here is the web for the url
        using (SPWeb web = site.OpenWeb())
        {
               //here is the file for the url
               SPFile file = web.GetFile("http://basesmcdev2/sites/tester1/tester4/A0805051340564172608.txt");

               //here is the list for the url
               SPList list = file.Item.ListItems.List;

               //here is the list item for the url
               SPListItem item = file.Item;
        }
 }