package main
import "fmt"
import "reflect"
// 用b的所有字段覆蓋a的
// 如果fields不為空, 表示用b的特定字段覆蓋a的
// a應(yīng)該為結(jié)構(gòu)體指針
func CopyFields(a interface{}, b interface{}, fields ...string) (err error) {
	at := reflect.TypeOf(a)
	av := reflect.ValueOf(a)
	bt := reflect.TypeOf(b)
	bv := reflect.ValueOf(b)
	// 簡單判斷下
	if at.Kind() != reflect.Ptr {
		err = fmt.Errorf("a must be a struct pointer")
		return
	}
	av = reflect.ValueOf(av.Interface())
	// 要復(fù)制哪些字段
	_fields := make([]string, 0)
	if len(fields) > 0 {
		_fields = fields
	} else {
		for i := 0; i < bv.NumField(); i++ {
			_fields = append(_fields, bt.Field(i).Name)
		}
	}
	if len(_fields) == 0 {
		fmt.Println("no fields to copy")
		return
	}
	// 復(fù)制
	for i := 0; i < len(_fields); i++ {
		name := _fields[i]
		f := av.Elem().FieldByName(name)
		bValue := bv.FieldByName(name)
		// a中有同名的字段并且類型一致才復(fù)制
		if f.IsValid() && f.Kind() == bValue.Kind() {
			f.Set(bValue)
		} else {
			fmt.Printf("no such field or different kind, fieldName: %s\n", name)
		}
	}
	return
}
type S1 struct {
    Name string
    Age int
}
type S2 struct {
    Name string
    Age int32
}
func main() {
    s1 := S1{"hello", 22}
    s2 := S2{"world", 33}
    fmt.Println(s1, s2)
    CopyFields(&s1, s2)
    fmt.Println(s1, s2)
}

package main
import (
	"fmt"
	"reflect"
)
type A struct {
	Name   string
	Gender string
	Age    int
}
type B struct {
	Name   string
	Gender string
}
//binding type interface 要修改的結(jié)構(gòu)體
//value type interace 有數(shù)據(jù)的結(jié)構(gòu)體
func structAssign(binding interface{}, value interface{}) {
	bVal := reflect.ValueOf(binding).Elem() //獲取reflect.Type類型
	vVal := reflect.ValueOf(value).Elem()   //獲取reflect.Type類型
	vTypeOfT := vVal.Type()
	for i := 0; i < vVal.NumField(); i++ {
		// 在要修改的結(jié)構(gòu)體中查詢有數(shù)據(jù)結(jié)構(gòu)體中相同屬性的字段，有則修改其值
		name := vTypeOfT.Field(i).Name
		if ok := bVal.FieldByName(name).IsValid(); ok {
			bVal.FieldByName(name).Set(reflect.ValueOf(vVal.Field(i).Interface()))
		}
	}
}
func main() {
	as := A{}
	bs := B{Name: "wfy", Gender: "男"}
	fmt.Println(as)
	structAssign(&as, &bs)
	fmt.Println(as)
}