简单结构

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

func (u User) Say() {
	fmt.Println("hello, world!")
}

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

	if kind := t.Kind(); kind != reflect.Struct {
		fmt.Println("Not reflect struct!!!")
		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("%s\t: %v = %v\n", f.Name, f.Type, val)
	}

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

func ModifyName(o interface{}, newName string) {
	v := reflect.ValueOf(o)
	if v.Kind() != reflect.Ptr {
		fmt.Println("is not pointer")
		return
	}

	if !v.Elem().CanSet() {
		fmt.Println("cannot set")
		return
	}

	v = v.Elem()
	f := v.FieldByName("Name")
	if !f.IsValid() {
		fmt.Println("name not found")
		return
	}

	if f.Kind() != reflect.String {
		fmt.Println("name is not string")
		return
	}

	f.SetString(newName)
}

func main() {
	user := User{123, "god", 33}
	PrintInfo(user)
	ModifyName(&user, "kelly")
	fmt.Println("new user info:", user)
}

输出：

Type: User
Fields:
Id	: int = 123
Name	: string = god
Age	: int = 33
Method:
Say	: func(main.User)
execute function: hello, world!
new user info: {123 kelly 33}

复杂结构

package main

import (
	"fmt"
	"reflect"
)

type User struct {
	Id   int
	Name string
	Age  int
}

func (u User) Say() {
	fmt.Println("hello, world!")
}

type Student struct {
	User
	Score int
}

func main() {
	user := User{123, "god", 15}
	student := Student{User: user, Score: 100}
	fmt.Println("student info:", student)

	t := reflect.TypeOf(student)
	fmt.Println("user name type:", t.FieldByIndex([]int{0, 1}))

	v := reflect.ValueOf(student)
	fmt.Println("user name value:", v.FieldByIndex([]int{0, 1}).Interface())
}

输出：

student info: {{123 god 15} 100}
user name type: {Name  string  8 [1] false}
user name value: god

[]int{0, 1}表示Student第0个元素是user，user的第1个元素是Name

修改变量

	i := 100
	v := reflect.ValueOf(&i)
	v.Elem().SetInt(99)
	fmt.Println(i)

输出：99