爬虫-（旧）51JOB职位数据

51JOB的数据相比BOSS直聘还是好做很多,首先还是在items.py中进行定义:

import scrapy


class PositionViewItem(scrapy.Item):
    # define the fields for your item here like:
    
    name :scrapy.Field = scrapy.Field()#名称
    salary :scrapy.Field = scrapy.Field()#薪资
    education :scrapy.Field = scrapy.Field()#学历
    experience :scrapy.Field = scrapy.Field()#经验
    jobjd :scrapy.Field = scrapy.Field()#工作ID
    district :scrapy.Field = scrapy.Field()#地区
    category :scrapy.Field = scrapy.Field()#行业分类
    scale :scrapy.Field = scrapy.Field()#规模
    corporation :scrapy.Field = scrapy.Field()#公司名称
    url :scrapy.Field = scrapy.Field()#职位URL
    createtime :scrapy.Field = scrapy.Field()#发布时间
    posistiondemand :scrapy.Field = scrapy.Field()#岗位职责
    cortype :scrapy.Field = scrapy.Field()#公司性质

然后也是采取直接搜索全国-数据分析职位的url作为起始url,记得需要模拟一个请求头:

    name :str = 'job51Analysis'
    url :str = 'https://search.51job.com/list/000000,000000,0000,00,9,99,%25E6%2595%25B0%25E6%258D%25AE%25E5%2588%2586%25E6%259E%2590,2,1.html?lang=c&postchannel=0000&workyear=99&cotype=99&degreefrom=99&jobterm=99&companysize=99&ord_field=0&dibiaoid=0&line=&welfare='

    headers :Dict = {
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0',
        'Referer': 'https://mkt.51job.com/tg/sem/pz_2018.html?from=baidupz'
    }

    def start_requests(self) -> Request:
        yield Request(self.url, headers=self.headers)

直接把定义好的headers作为参数传进Request里就可以了.

首先也是用默认的回调函数parse(比较懒,临时用就没有自定义):

        if response.status == 200:
            PositionInfos :selector.SelectorList = response.selector.xpath(r'//div[@class="el"]')

如何取得单个职位的信息呢?首先用xpath把单个职位的list选出来,之后再用这个list去二次选择,这样就可以获取了.

            for positioninfo in PositionInfos:#遍历取得的selectorlist
                pvi = PositionViewItem()
                pvi['name'] :str = ''.join(positioninfo.xpath(r'p[@class="t1 "]/span/a/text()').extract()).strip()
                pvi['salary'] :str = ''.join(positioninfo.xpath(r'span[@class="t4"]/text()').extract())
                pvi['createtime'] :str = ''.join(positioninfo.xpath(r'span[@class="t5"]/text()').extract())
                pvi['district'] :str = ''.join(positioninfo.xpath(r'span[@class="t3"]/text()').extract())
                pvi['corporation'] :str = ''.join(positioninfo.xpath(r'span[@class="t2"]/a/text()').extract()).strip()
                pvi['url'] :str = ''.join(positioninfo.xpath(r'p[@class="t1 "]/span/a/@href').extract())

由于51JOB中的职位信息用一层搜索是看不全的,需要点击进去处理下一层路径,因此在这里获取职位详细信息的url,之后进行下一级处理:

                #处理二级路径
                if len(pvi['url']) > 0:
                    request :Request = Request(pvi['url'], callback=self.positiondetailparse, headers=self.headers)
                    request.meta['positionViewItem'] = pvi
                    yield request

以上的代码用到了自定义的callback函数,用来对二级路径进行处理,另外在request中加入了meta属性,可以用来把参数通过request进行传递(这个好像是get请求,所以不建议传太长,不太安全也不规范),这样的话在positiondetailparse这个方法中就可以获取传过去的item实例了.

    def positiondetailparse(self, response) -> PositionViewItem:
        if response.status == 200:
            pvi :PositionViewItem = response.meta['positionViewItem']
            pvi['posistiondemand'] :str = ''.join(response.selector.xpath(r'//div[@class="bmsg job_msg inbox"]//p/text()').extract()).strip()
            pvi['cortype'] :str = ''.join(response.selector.xpath(r'//div[@class="com_tag"]/p[@class="at"][1]/@title').extract()).strip()#xpath从1开始需要注意
            pvi['scale'] :str = ''.join(response.selector.xpath(r'//div[@class="com_tag"]/p[@class="at"][2]/@title').extract()).strip()
            pvi['category'] :str = ''.join(response.selector.xpath(r'//div[@class="com_tag"]/p[@class="at"][3]/@title').extract())
            pvi['education'] :str = ''.join(response.selector.xpath(r'//p[@class="msg ltype"]/text()[3]').extract()).strip()
            yield pvi

解析二级路径中的信息,需要注意的是xpath选择器中的元素个数是从1开始的,不是0.

把所有的信息取得之后,返回一个pvi给pipeline,用来进行处理和存储.

单个职位信息抓取完成之后,自然也需要下一页的信息,在parse中:

            nexturl = ''.join(response.selector.xpath(r'//li[@class="bk"][2]/a/@href').extract())
            print(nexturl)
            if nexturl:
                # nexturl = urljoin(self.url, ''.join(nexturl))
                print(nexturl)
                yield Request(nexturl, headers=self.headers)

如果不加callback参数,就会默认调用parse这个方法,从而达到解析下一页的目的.

最后要在pipelines.py里加入处理item数据的程序,这里我选择把数据存到csv当中.

import os
import csv

class LearningPipeline(object):

    def __init__(self):
        self.file = open('51job.csv', 'a+', encoding='utf-8', newline='')
        self.writer = csv.writer(self.file, dialect='excel')

    def process_item(self, item, spider):
        if item['name']:
            self.writer.writerow([item['name'], item['salary'], item['district'], item['createtime'], item['education'],
            item['posistiondemand'], item['corporation'], item['cortype'], item['scale'], item['category']])
        return item

    def close_spider(self, spider):
        self.file.close()

初始化方法里默认打开这个文件,然后process_item是默认的处理item 的方法,返回一个item就会调用一次!

close_spider方法是关闭爬虫时用的,写一个关闭文件就可以了.

需要注意的是输出的csv文件用excel打开是有中文乱码的,我把文件用记事本打开之后以ASCII的方式另存一份,乱码就消失了.

好了,接下来就可以开始运行爬虫了,这只是一个非常初级的爬虫,也很简易.留着备忘吧!