目的

給定網址，以及儲存檔案，將該網頁內全部網址採集下，可指定檔案儲存。

思路

用lxml解析工具解析請求的文字，分析網頁中url在的位置以及標籤會出現三種情況：

1. 通過href獲取的格式正確的url。
2. 通過href獲取的為”javascript”開頭的，跳過。

程式碼

#coding:utf-8
# 網頁url採集爬蟲，給定網址，以及儲存檔案，將該網頁內全部網址採集下，可指定檔案儲存方式
#[email protected] 許娜
#os    : ubuntu16.04
#python: python2
import requests,time
from
 
 lxml import etree
"""
    url:給定的url
    save_file_name:為url儲存檔案
"""
def Redirect(url):
    try:
        res = requests.get(url,timeout=10)
        url = res.url
    except Exception as e:
        print("4",e)
        time.sleep(1)
    return url

def requests_for_url(url, save_file_name, file_model)
 
:
    headers = {
        'pragma': "no-cache",
        'accept-encoding': "gzip, deflate, br",
        'accept-language': "zh-CN,zh;q=0.8",
        'upgrade-insecure-requests': "1",
        'user-agent': "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36"
 
,
        'accept': "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8",
        'cache-control': "no-cache",
        'connection': "keep-alive",
        }
    try:
        response = requests.request("GET", url, headers=headers)
        selector = etree.HTML(response.text, parser=etree.HTMLParser(encoding='utf-8'))
    except Exception as e:
        print ("頁面載入失敗", e)
    return_set = set()
    with open(save_file_name,file_model) as f:
        try:
            context = selector.xpath('//a/@href')
            for i in context:
                try:
                    if i[0] == "j":
                        continue
                    if i[0] == "/":
                        print i
                        i = url+i.replace("/","");
                    f.write(i)
                    f.write("\n")
                    return_set.add(i)                                     
                    print(len(context),context[0],i)
                except Exception as e:
                    print("1",e)
        except Exception as e:
            print("2",e)
    return return_set


if __name__ == '__main__':
     # 網頁url採集爬蟲，給定網址，以及儲存檔案，將該網頁內全部網址採集下，可指定檔案儲存方式
     url = "http://news.baidu.com/"
     save_file_name = "save_url_2.txt"
     return_set = requests_for_url(url,save_file_name,"a") #“a”:追加
     print(len(return_set))