go 反射

反射

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

func (u User) Hello() {
	fmt.Println("Hello World")
}

func main() {
	u := User{1, "ok", 12}
	Info(u)
}

func Info(o interface{}) {
	t := reflect.TypeOf(o)
	fmt.Println("Type:", t.Name())

	if k := t.Kind(); k != reflect.Struct {
		fmt.Println("xxxx")
		return
	}

	v := reflect.ValueOf(o)
	fmt.Println("Fields:")

	for i := 0; i < t.NumField(); i++ {
		f := t.Field(i)
		val := v.Field(i).Interface()
		fmt.Printf("%6s: %v = %v\n", f.Name, f.Type, val)
	}

	for i := 0; i < t.NumMethod(); i++ {
		m := t.Method(i)
		fmt.Printf("%6s: %v\n", m.Name, m.Type)
	}

}

获取字段内容

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

type Manager struct {
	User
	title string
}

func main() {
	m := Manager{User: User{1, "ok", 12}, title: "123"}
	t := reflect.TypeOf(m)

	fmt.Printf("%#v\n", t.FieldByIndex([]int{0, 0}))
}

通过反射修改基本类型

package main

import (
	"fmt"
	"reflect"
)

func main() {
	x := 123
	v := reflect.ValueOf(&x)
	v.Elem().SetInt(999)
	fmt.Println(x)
}

通过反射对接口中的对象的值进行修改

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

func main() {
	u := User{1, "ok", 12}
	Set(&u)
	fmt.Println(u)
}

func Set(o interface{}) {
	v := reflect.ValueOf(o)
	if v.Kind() == reflect.Ptr && !v.Elem().CanSet() {
		fmt.Println("xx")
		return
	}

	v = v.Elem()
	f := v.FieldByName("Name")
	if !f.IsValid() {
		fmt.Println("BAD")
		return
	}
	if f.Kind() == reflect.String {
		f.SetString("BYEBYE")
	}
}

通过反射进行方法调用

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

func (u User) Hello(name string) {
	fmt.Println("Hello", name, ", my name is", u.Name)
}

func main() {
	u := User{1, "ok", 12}
	u.Hello("wang")

	v := reflect.ValueOf(u)
	mv := v.MethodByName("Hello")
	args := []reflect.Value{reflect.ValueOf("wang")}

	mv.Call(args)
}