config.Filters.Add(new AuthorizeAttribute());

　　[Authorize]

　　public class HelloController : ApiController

    {

        public string GetTest()

        {

            return "hello,world";

        }

    }

    public class HelloController : ApiController

    {

        [Authorize]

        public string GetTest()

        {

            return "hello,world";

        }

    }

    [Authorize]

    public class HelloController : ApiController

    {

        [AllowAnonymous]

        public string GetTest()

        {

            return "hello,world1";

        }

        public string PostTest()

        {

            return "hello,world2";

        }

    }