博客

package main

import (
	"bytes"
	"expvar"
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"os/exec"
	"strconv"
	"sync"
)

// hello world, the web server
var helloRequests = expvar.NewInt("hello-requests")

func HelloServer(w http.ResponseWriter, req *http.Request) {
	helloRequests.Add(1)
	io.WriteString(w, "hello, world!\n")
}

// Simple counter server. POSTing to it will set the value.
type Counter struct {
	mu sync.Mutex // protects n
	n  int
}

// This makes Counter satisfy the expvar.Var interface, so we can export
// it directly.
func (ctr *Counter) String() string {
	ctr.mu.Lock()
	defer ctr.mu.Unlock()
	return fmt.Sprintf("%d", ctr.n)
}

func (ctr *Counter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	ctr.mu.Lock()
	defer ctr.mu.Unlock()
	switch req.Method {
	case "GET":
		ctr.n++
	case "POST":
		bu