GoLang上的反射错误-参数太少

Question

我有这个控制器：

package web

import (
    "net/http"
)

func init() {

}

func (controller *Controller) Index(r *http.Request) (string, int) {
    return "Testing", http.StatusOK
}

使用此处理程序：

type Application struct {
}

func (application *Application) Route(controller interface{}, route string) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {

        var ptr reflect.Value
        var value reflect.Value
        var finalMethod reflect.Value

        value = reflect.ValueOf(controller)

        // if we start with a pointer, we need to get value pointed to
        // if we start with a value, we need to get a pointer to that value
        if value.Type().Kind() == reflect.Ptr {
            ptr = value
            value = ptr.Elem()
        } else {
            ptr = reflect.New(reflect.TypeOf(controller))
            temp := ptr.Elem()
            temp.Set(value)
        }

        // check for method on value
        method := value.MethodByName(route)
        if method.IsValid() {
            finalMethod = method
        }
        // check for method on pointer
        method = ptr.MethodByName(route)
        if method.IsValid() {
            finalMethod = method
        }

        methodInterface := finalMethod.Call([]reflect.Value{})[0].Interface()
        method_route := methodInterface.(func(r *http.Request) (string, int))
        body, code := method_route(r)
        switch code {
        case http.StatusOK:
            io.WriteString(w, body)
        case http.StatusSeeOther, http.StatusFound:
            http.Redirect(w, r, body, code)
        default:
            w.WriteHeader(code)
            io.WriteString(w, body)
        }
    }
}

并以这种方式执行：

controller := &web.Controller{}
application := &system.Application{}

http.HandleFunc("/", application.Route(controller, "Index"))

问题是编译好了。它没有显示任何错误，但是当我转到网站时，仅指向localhost，它显示：

2014/12/27 22:38:16 http: panic serving 127.0.0.1:58304: reflect: Call with too few input arguments
goroutine 20 [running]:
net/http.func·011()
    /usr/local/Cellar/go/1.3.3/libexec/src/pkg/net/http/server.go:1100 +0xb7

我找不到任何错误，而且编译还可以，这很奇怪…我是Go语言的新手，所以我不知道发生了什么…

Answer 1

我通过阅读以下内容找到了答案：

http://codingdict.com/questions/63176

因此，与其尝试调用该方法，不如：

    methodInterface := finalMethod.Call([]reflect.Value{})[0].Interface()
    method_route := methodInterface.(func(r *http.Request) (string, int))
    body, code := method_route(r)

我只是获得所需的接口，然后将其转换为函数并如此调用它。

    methodInterface := finalMethod.Interface()
    method_route := methodInterface.(func(r *http.Request) (string, int))
    body, code := method_route(r)

实际上，这就是我已经在做的事情，但是方式错误。