package main

import (
	"net/http"
	"sync"
)

func main() {
	var wg sync.WaitGroup
	var urls = []string{
		"http://www.baidu.com/",
		"http://www.somestupidname.com/",
	}
	for _, url := range urls {
		// 添加WaitGroup 计数器.
		wg.Add(1)
		// 运行一个协程去获取 URL.
		go func(url string) {
			// 当协程结束时，计数器减一
			defer wg.Done()
			// 获取 URL.
			http.Get(url)
		}(url)
	}
	// 等待所有url获取完成
	wg.Wait()
}