假設我有一個結構用戶type User struct { Name string `owm:"newNameFromAPI"`}下面的代碼初始化結構并將其傳遞給函數func main() { dest := User{ Name: "Sebastien", } deepUpdate(dest, "owm")}該函數使用反射來迭代結構的所有字段并相應地更新它們（為清楚起見，刪除了幾個代碼塊）func deepUpdate(destinationInterface interface{}, selector string) { // Here I'm not supposed to know that the type is `User` // And if I just use dest := destinationInterface, the value won't update dest := destinationInterface.(User) // Pointer to struct - addressable destVal := reflect.ValueOf(&dest) destType := reflect.TypeOf(&dest) // psindirect := reflect.Indirect(destVal) // ? ValueOf(<Ptr Value>) Requires to be adressed via reflect.Indirect() to access Field - https://stackoverflow.com/a/50098755/9077800 // Struct destValElem := destVal.Elem() destTypeElem := destType.Elem() // Iterate over all fields of the struct for i := 0; i < destValElem.NumField(); i++ { // // for i := 0; i < destTypeElem.NumField(); i++ { destValField := destValElem.Field(i) destTypeField := destTypeElem.Field(i) switch destValField.Kind() { // Field is a struct case reflect.Struct: // Recursion fmt.Println("IS A STRUCT") default: // Get the complete tag tag := destTypeField.Tag if len(tag) == 0 { continue } // Get the value of our custom tag key tagVal := tag.Get(selector) if len(tagVal) == 0 { continue } }問題是以下行，因為我不應該知道要將 轉換為 .destinationInterfaceUser如何將接口動態轉換為在運行時定義的某個未知類型，或者以任何其他方式獲取更新的“John”而不是“Sebastien”的相同輸出？Namedest := destinationInterface.(User)這是在戈朗游戲狗上運行的完整代碼https://play.golang.org/p/sYvz-Fwp97P
1 回答
至尊寶的傳說
TA貢獻1789條經驗 獲得超10個贊
您不必知道 .該示例不是遞歸的，但可以輕松升級。dest
package main
import (
"fmt"
"reflect"
)
type User struct {
Name string `owm:"newNameFromAPI"`
}
func main() {
dest := User{
Name: "Sebastien",
}
fmt.Println("Before:", dest.Name)
deepUpdate(&dest, "owm")
fmt.Println("After:", dest.Name)
}
func deepUpdate(dest interface{}, selector string) {
//Get the reflect value of dest
rv := reflect.ValueOf(dest)
//Dereference every pointers
for rv.Kind() == reflect.Ptr {
rv = reflect.Indirect(rv)
}
//Check if its a struct, should use panic or return error
if reflect.TypeOf(rv.Interface()).Kind() != reflect.Struct {
fmt.Println("NOT A STRUCT")
return
}
//Loop over the fields
for i := 0; i < rv.NumField(); i++ {
//Get the tag value
tag := rv.Type().Field(i).Tag.Get(selector)
if tag == "" {
continue
}
//Get the source
sourceValue := "John"
//Assign the source to the dest's corresponding field
if rv.Field(i).CanSet() {
rv.Field(i).Set(reflect.ValueOf(sourceValue))
}
}
}
唯一的問題是，您必須使用與相應字段相同的類型。sourceValue
工作示例：https://goplay.space/#D0CmTaS5AiP
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