golang 设置 Header Content-type

直接贴代码

package main

import (
	"io"
	"net/http"
	"encoding/json"
)

type KPI struct{
	Fzi int `json:"fenzi"` //分子
	Fmu int	`json:"fenmu"`	//分母
}

func kpi(w http.ResponseWriter, r *http.Request){	
	kk := KPI{199, 200}
	res,_ := json.Marshal(kk)
	w.Header().Set("content-type","application/json")
	io.WriteString(w, string(res))
}

func main() {
	http.HandleFunc("/", kpi)
	http.ListenAndServe(":9999", nil)
}

验证结果