golang 如何使用反射实现动态代理模式

type UserService struct{}

func (s *UserService) GetUser(id int) (*User, error) {
    // 获取用户数据
    return &User{}, nil
}

type ProxyUserService struct {
    targetUserService *UserService
    preHook           func()
    postHook          func()
}

func (p *ProxyUserService) GetUser(id int) (*User, error) {
    if p.preHook != nil {
        p.preHook()
    }

    result, err := p.targetUserService.GetUser(id)

    if p.postHook != nil {
        p.postHook()
    }

    return result, err
}

func main() {
    userService := &UserService{}
    proxyService := &ProxyUserService{
        targetUserService: userService,
        preHook: func() {
            fmt.Println("Pre-hook logic")
        },
        postHook: func() {
            fmt.Println("Post-hook logic")
        },
    }

    user, err := proxyService.GetUser(1)
    if err != nil {
        // 处理错误
    }

    fmt.Println(user)
}

Pre-hook logic
Post-hook logic
{1 <user data>}