diff --git a/web/fasthttp/server-handler.go b/web/fasthttp/server-handler.go
index 8cbc74b..aee1f42 100644
--- a/web/fasthttp/server-handler.go
+++ b/web/fasthttp/server-handler.go
@@ -99,7 +99,7 @@ func (sh *ServerHandlers) RegisterServlet(contextPath string, servlet Servlet) {
 	if nil == sh.servlets {
 		sh.servlets = make(map[string]Servlet)
 	}
-	servlet.(*Servlets).ContextPath = contextPath
+	servlet.setContextPath(contextPath)
 	sh.servlets[contextPath] = servlet
 }
 
diff --git a/web/fasthttp/servlet.go b/web/fasthttp/servlet.go
index 15ff414..d227edf 100644
--- a/web/fasthttp/servlet.go
+++ b/web/fasthttp/servlet.go
@@ -13,6 +13,7 @@ type Servlet interface {
 
 	Handle(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx) *web.Error
 	RequestPath(ctx *fasthttp.RequestCtx) string
+	setContextPath(contextPath string)
 }
 
 type Servlets struct {
@@ -45,6 +46,10 @@ func (s *Servlets) Handle(servletCtx server.ServletCtx, ctx *fasthttp.RequestCtx
 	return nil
 }
 
+func (s *Servlets) setContextPath(contextPath string) {
+	s.ContextPath = contextPath
+}
+
 func (s *Servlets) RequestPath(ctx *fasthttp.RequestCtx) string {
 	return strings.Replace(string(ctx.Path()), s.ContextPath, "", -1)
 }