scrapy爬取猫眼电影排行榜

做爬虫的人,一定离不开的一个框架就是scrapy框架,写小项目的时候可以用requests模块就能得到结果,但是当爬取的数据量大的时候,就一定要用到框架.

下面先练练手,用scrapy写一个爬取猫眼电影的程序,环境配置和scrapy安装略过

第一步肯定是终端运行创建爬虫项目和文件

 # 创建爬虫项目
 scrapy startproject Maoyan
 cd Maoyan
 # 创建爬虫文件
 scrapy genspider maoyan maoyan.com

然后在产生的items.py文件夹中定义需要爬取的数据结构

 name = scrapy.Field()
 star = scrapy.Field()
 time = scrapy.Field()

之后打开maoyan.py文件,编写爬虫文件,记得导入items.py文件的MaoyanItem类,并实例化

 import scrapy
 from ..items import MaoyanItem
 ​
 class MaoyanSpider(scrapy.Spider):
     name = 'maoyan3'
     allowed_domains = ['maoyan.com']
     # 去掉start_urls变量
 ​
     # 重写start_requests()方法
     def start_requests(self):
         for offset in range(0,91,10):
             url = 'https://maoyan.com/board/4?offset={}'.format(offset)
             yield scrapy.Request(url=url,callback=self.parse)
 ​
     def parse(self, response):
         # 给items.py中的类:MaoyanItem(scrapy.Item)实例化
         item = MaoyanItem()
 ​
         # 基准xpath
         dd_list = response.xpath('//dl[@class="board-wrapper"]/dd')
         # 依次遍历
         for dd in dd_list:
             # 是在给items.py中那些类变量赋值
             item['name'] = dd.xpath('./a/@title').get().strip()
             item['star'] = dd.xpath('.//p[@class="star"]/text()').get().strip()
             item['time'] = dd.xpath('.//p[@class="releasetime"]/text()').get().strip()
 ​
             # 把item对象交给管道文件处理
             yield item

定义管道文件pipelines.py,进行持久化储存

 class MaoyanPipeline(object):
     # item: 从爬虫文件maoyan.py中yield的item数据
     def process_item(self, item, spider):
         print(item['name'],item['time'],item['star'])
 ​
         return item
 ​
 ​
 import pymysql
 from .settings import *
 ​
 # 自定义管道 - MySQL数据库
 class MaoyanMysqlPipeline(object):
     # 爬虫项目开始运行时执行此函数
     def open_spider(self,spider):
         print('我是open_spider函数输出')
         # 一般用于建立数据库连接
         self.db = pymysql.connect(
             host = MYSQL_HOST,
             user = MYSQL_USER,
             password = MYSQL_PWD,
             database = MYSQL_DB,
             charset = MYSQL_CHAR
         )
         self.cursor = self.db.cursor()
 ​
     def process_item(self,item,spider):
         ins = 'insert into filmtab values(%s,%s,%s)'
         # 因为execute()的第二个参数为列表
         L = [
             item['name'],item['star'],item['time']
         ]
         self.cursor.execute(ins,L)
         self.db.commit()
 ​
         return item
 ​
     # 爬虫项目结束时执行此函数
     def close_spider(self,spider):
         print('我是close_spider函数输出')
         # 一般用于断开数据库连接
         self.cursor.close()
         self.db.close()

接下来就是修改配置文件settings.py

 USER_AGENT = 'Mozilla/5.0'
 ROBOTSTXT_OBEY = False
 DEFAULT_REQUEST_HEADERS = {
   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
   'Accept-Language': 'en',
 }
 ITEM_PIPELINES = {
    'Maoyan.pipelines.MaoyanPipeline': 300,
    'Maoyan.pipelines.MaoyanMysqlPipeline':200,
 }
 # 定义MySQL相关变量
 MYSQL_HOST = '127.0.0.1'
 MYSQL_USER = 'root'
 MYSQL_PWD = ''
 MYSQL_DB = 'maoyandb'
 MYSQL_CHAR = 'utf8'

最后,是创建run.py文件,然后就可以运行了

 from scrapy import cmdline
 cmdline.execute('scrapy crawl maoyan'.split())