0
我想使用反射來調用一個結構上的方法。但是,即使attachMethodValue
和args
都不爲零,我仍得到panic: runtime error: invalid memory address or nil pointer dereference
。任何想法可能是什麼?Go反映方法調用無效的內存地址或零指針解除引用
去遊樂場:http://play.golang.org/p/QSVTSkNKam
package main
import "fmt"
import "reflect"
type UserController struct {
UserModel *UserModel
}
type UserModel struct {
Model
}
type Model struct {
transactionService *TransactionService
}
func (m *Model) Attach(transactionService *TransactionService) {
m.transactionService = transactionService
}
type Transactioner interface {
Attach(transactionService *TransactionService)
}
type TransactionService struct {
}
func main() {
c := &UserController{}
transactionService := &TransactionService{}
valueField := reflect.ValueOf(c).Elem().Field(0) // Should be UserController.UserModel
// Trying to call this
attachMethodValue := valueField.MethodByName("Attach")
// Argument
args := []reflect.Value{reflect.ValueOf(transactionService)}
// They're both non-nil
fmt.Printf("%+v\n", attachMethodValue)
fmt.Println(args)
// PANIC!
attachMethodValue.Call(args)
fmt.Println("The end.")
}
哪條線是線29?代碼恐慌 – Topo 2015-02-24 20:47:11
我會認爲問題出現在'val:= reflect.ValueOf(c.AppController).Elem()' – Topo 2015-02-24 20:51:50
或者可能是在調用'attachMethodValue.Call(args)'時發生的事情。無論哪種方式,我們都需要錯誤的確切位置。 – 2015-02-24 21:15:39