返回 JSON 响应

package main

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

func hello(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	_ = json.NewEncoder(w).Encode(map[string]any{
		"code": 200,
		"msg":  "ok",
	})
}