Add the file downloader.

rest/bean.go

@@ -1,8 +1,11 @@
 package rest
 
+import "net/http"
+
 type IBean interface {
 	Init(context *Context)
 	PanicError(err error);
+	PanicWebError(msg string, code int);
 }
 
 type Bean struct {
@@ -16,6 +19,11 @@ func (this *Bean) Init(context *Context) {
 //处理错误的统一方法
 func (this *Bean) PanicError(err error) {
 	if err != nil {
-		panic(err)
+		panic(&WebError{Msg: err.Error(), Code: http.StatusInternalServerError})
 	}
 }
+
+//处理错误的统一方法
+func (this *Bean) PanicWebError(msg string, httpStatusCode int) {
+	panic(&WebError{Msg: msg, Code: httpStatusCode})
+}