运行这段代码并在浏览器中访问 http://localhost:8080 ``` package main import "github.com/gin-gonic/gin" func main() { r := gin.Default() r.GET("/ping", func(c *gin.Context) { c.JSON(200, gin.H{ "message": "pong", }) }) r.Run() // listen and serve on 0.0.0.0:8080 } ```