#main.py

    import requests
    import json
    import pymongo
    from multiprocessing import Pool
    import time
    import random


    url = 'https://www.lagou.com/jobs/positionAjax.json?needAddtionalResult=false'
    headers = {
        'Accept':'application/json, text/javascript, */*; q=0.01',
        'Accept-Encoding':'gzip, deflate',
        'Accept-Language':'zh-CN,zh;q=0.8',
        'Connection':'keep-alive',
        'Content-Length':'65',
        'Content-Type':'application/x-www-form-urlencoded; charset=UTF-8',
        'Cookie':'',
        'Host':'www.lagou.com',
        'Origin':'https://www.lagou.com',
        'Referer':'https://www.lagou.com/jobs/list_%E6%95%B0%E6%8D%AE%E5%88%86%E6%9E%90%E5%B8%88?px=default&city=%E5%85%A8%E5%9B%BD',
        'User-Agent':'Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.130 Safari/537.36',
        'X-Anit-Forge-Code':'0',
        'X-Anit-Forge-Token':'None',
        'X-Requested-With':'XMLHttpRequest'
    }


    def postonepage(pn):
        client = pymongo.MongoClient('localhost', 27017)
        Lagou = client['Lagou']
        position = Lagou['position']
        print(pn)
        postdata = {
            'first': 'false',
            'pn': pn,
            'kd': '数据分析师'
        }
        try:
            wbdata = requests.post(url,headers = headers,data = postdata)
            jdata = wbdata.json()
            # print(jdata)
            positionResult = jdata['content']['positionResult']
            time.sleep(random.randint(4, 8))
            # print(positionResult)
            for j in positionResult:
                i = j['position']
                adata = {
                    'createTime':i['createTime'],
                    'positionId': i['positionId'],
                    'positionName':i['positionName'],
                    'firstType':i['firstType'],
                    'secondType':i['secondType'],
                    'education':i['education'],
                    'city':i['city'],
                    'salary':i['salary'],
                    'jobNature':i['jobNature'],
                    'workYear':i['workYear'],

                    'companyId':i['companyId'],
                    'companyFullName':i['companyFullName'],
                    'financeStage':i['financeStage'],
                    'companySize':i['companySize'],
                    'industryField':i['industryField']
                }
                position.insert_one(adata)

            print('success')
        except:
            print('one error occurred')


    if __name__ == '__main__':
        alist = list(range(1,500))
        pool = Pool(processes=4)
        pool.map(postonepage,alist)