Code

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"sync"
)

func main() {
	urls := []string{
		"http://llever.com",
		"http://llever.com/goreleaser-zh",
		"http://llever.com/about/",
	}
	jsonResponses := make(chan int)

	var wg sync.WaitGroup

	all := 0

	for _, url := range urls {
		wg.Add(1)
		all++

		go getURL(url, &wg, jsonResponses)
	}

	index := 0
	for response := range jsonResponses {
		index++
		fmt.Println(response)
		if all == index {
			close(jsonResponses)
		}
	}

	fmt.Println("before done")

	wg.Wait()
}

func getURL(url string, wg *sync.WaitGroup, jsonResponses chan<- int) {
	defer wg.Done()
	fmt.Println(url)
	res, err := http.Get(url)
	if err != nil {
		log.Fatal(err)
	} else {
		defer res.Body.Close()
		body, err := ioutil.ReadAll(res.Body)
		if err != nil {
			log.Fatal(err)
		} else {
			jsonResponses <- len(body)
			fmt.Println("postsend")
		}
	}
}