main.go

package main

import (
	"fmt"

	"github.com/go-playground/validator/v10"
)

type Hoge struct {
	Num  string `validate:"number"`
	Date string `validate:"datetime=20060102"`
}

func main() {
	h := Hoge{Num: "1234.01", Date: "20201231"}
	validate := validator.New()
	err := validate.Struct(h)
	if err != nil {
		fmt.Println(err)
	} else {
		fmt.Printf("%+v\n", h)
	}
}