我们上一篇已经提到了gin中binding时候可以指定json字段大小等限制，但是那个错误却是英文的，现在想搞成中文的，以便前端可读，demo如下

package main

import (
	"net/http"
	"reflect"

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

// binding 指明了json字段的限制，msg是自定义的错误提醒
type UserInfo struct {
	UserName  string `json:"username" binding:"required,min=4,max=6" msg:"username验证失败"`
	Age       int    `json:"age" binding:"gt=18,lte=120" msg:"age验证失败"`
	Password  string `json:"password" binding:"required" msg:"密码校验失败"`
	Password2 string `json:"password2" binding:"required,eqfield=Password" msg:"必填，切要与password一致"`
}

//any是泛型

func CoustomError(err error, obj any) map[string]string {
	var errors map[string]string = make(map[string]string)
	if err2, ok := err.(validator.ValidationErrors); ok {
		// 反射
		getObj := reflect.TypeOf(obj)
		// 循环错误的验证
		for _, v := range err2 {
			if sf, exist := getObj.Elem().FieldByName(v.Field()); exist {
				// 获取结构体中的msg属性
				errors[v.Field()] = sf.Tag.Get("msg")
			}
		}
		return errors
	}
	return nil
}

func validationcustomerror(c *gin.Context) {
	var user UserInfo
	err := c.ShouldBindJSON(&user)
	if err != nil {
		errors := CoustomError(err, &user)
		c.JSON(http.StatusBadRequest, gin.H{"msg": errors})
	} else {
		c.JSON(http.StatusOK, gin.H{"msg": user})
		return
	}
}

func main() {
	router := gin.Default()
	router.POST("/validationcustomerror", validationcustomerror)
	router.Run("localhost:8888")
}