type barForm struct {
    Foo string  `form:"foo" binding:"required"`
    Bar int     `form:"bar" binding:"required"`
}

func (fooHdl FooHdl) Bar(c *gin.Context) {
    var bform = new(barForm)
    if err := c.ShouldBind(bform); err != nil {
        // true: parse form error
        return
    }

    // handle biz logic and generate response structure
    // c (gin.Context) methods could called to support process-controling

    c.JSON(http.StatusOK, resp)
    // c.String() alse repsonse to client
}

// mountRouters .
func mountRouters(engi *gin.Engine) {
    // use middlewares
    engi.Use(gin.Logger())
    engi.Use(gin.Recovery())
    
    // mount routers
    group := engi.Group("/v1")
    {
        fooHdl := demohtp.New()
        group.GET("/foo", fooHdl.Bar)
        group.GET("/echo", fooHdl.Echo)
        // subGroup := group.Group("/subg")
        // subGroup.GET("/hdl1", fooHdl.SubGroupHdl1) // 最终路由："targetURI = /v1/subg/hdl1"
    }
}

func main() {
    engi := gin.New()

    mountRouters(engi)

    if err := engi.Run(":8080"); err != nil {
        log.Fatalf("engi exit with err=%v", err)
    }
}