go语言实现百度贴吧并发爬虫

package main

import (
	"net/http"
	"io"
	"strconv"
	"fmt"
	"os"
)

func get(url string) (re string,e error) {
	resp,err:=http.Get(url)
	if err!=nil {
		e=err
		return
	}
	defer resp.Body.Close()
	buf:=make([]byte,4096)
	for  {
		n,err:=resp.Body.Read(buf)
		re+=string(buf[:n])
		if err!=nil {
			if err==io.EOF {
				break
			} else {
				e=err
				return
			}
		}
	}
	return
}

func spider(start int,end int)  {
	m:=make(chan int)
	for i:=start; i<=end; i++ {
		go func(i int) {
			re,err:=get("https://tieba.baidu.com/f?kw=%E7%BB%9D%E5%9C%B0%E6%B1%82%E7%94%9F&ie=utf-8&pn="+strconv.Itoa(50*(i-1)))
			if err!=nil {
				fmt.Print(err)
				return
			}
			fp,err:=os.Create("/Users/zmx/"+strconv.Itoa(i)+".txt")
			if err!=nil {
				fmt.Print(err)
				return
			}
			defer fp.Close()
			fp.WriteString(re)
			m<-i
		}(i)
	}
	for i:=start; i<=end; i++ {
		<-m
	}
}

func main()  {
	var start int
	fmt.Scan(&start)
	var end int
	fmt.Scan(&end)
	spider(start,end)
}