GoLang 上的反射错误 - 参数太少

Question

我有这个控制器：

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package web\n\nimport (\n    "net/http"\n)\n\nfunc init() {\n\n}\n\nfunc (controller *Controller) Index(r *http.Request) (string, int) {\n    return "Testing", http.StatusOK\n}\n

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使用此处理程序：

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type Application struct {\n}\n\nfunc (application *Application) Route(controller interface{}, route string) http.HandlerFunc {\n    return func(w http.ResponseWriter, r *http.Request) {\n\n        var ptr reflect.Value\n        var value reflect.Value\n        var finalMethod reflect.Value\n\n        value = reflect.ValueOf(controller)\n\n        // if we start with a pointer, we need to get value pointed to\n        // if we start with a value, we need to get a pointer to that value\n        if value.Type().Kind() == reflect.Ptr {\n            ptr = value\n            value = ptr.Elem()\n        } else {\n            ptr = reflect.New(reflect.TypeOf(controller))\n            temp := ptr.Elem()\n            temp.Set(value)\n        }\n\n        // check for method on value\n        method := value.MethodByName(route)\n        if method.IsValid() {\n            finalMethod = method\n        }\n        // check for method on pointer\n        method = ptr.MethodByName(route)\n        if method.IsValid() {\n            finalMethod = method\n        }\n\n        methodInterface := finalMethod.Call([]reflect.Value{})[0].Interface()\n        method_route := methodInterface.(func(r *http.Request) (string, int))\n        body, code := method_route(r)\n        switch code {\n        case http.StatusOK:\n            io.WriteString(w, body)\n        case http.StatusSeeOther, http.StatusFound:\n            http.Redirect(w, r, body, code)\n        default:\n            w.WriteHeader(code)\n            io.WriteString(w, body)\n        }\n    }\n}\n

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它是这样执行的：

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controller := &web.Controller{}\napplication := &system.Application{}\n\nhttp.HandleFunc("/", application.Route(controller, "Index"))\n

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问题是编译没问题。它没有显示任何错误，但是当我访问该网站时，只需指向 localhost，它就会显示：

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2014/12/27 22:38:16 http: panic serving 127.0.0.1:58304: reflect: Call with too few input arguments\ngoroutine 20 [running]:\nnet/http.func\xc2\xb7011()\n    /usr/local/Cellar/go/1.3.3/libexec/src/pkg/net/http/server.go:1100 +0xb7\n

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我找不到任何错误，更奇怪的是它编译正常...我是 Go 新手，所以我不知道发生了什么...

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Answer 1

我通过阅读这篇文章找到了答案：

/sf/answers/1450054721/

因此，不要尝试调用该方法：

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

我只是获得我需要的接口，然后将其转换为函数并这样调用它。

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

事实上，这就是我已经在做的事情，但方式错误。