python爬虫案例：爬取⾖瓣电影 top250，的电影数据，并保存在 MongoDB 中

1、items.py

class DoubanspiderItem(scrapy.Item): # 电影标题
title = scrapy.Field()
# 电影评分
score = scrapy.Field()
# 电影信息
content = scrapy.Field()
# 简介
info = scrapy.Field()

2、spiders/douban.py

import scrapy
from doubanSpider.items import DoubanspiderItem
class DoubanSpider(scrapy.Spider):
name = "douban"
allowed_domains = ["movie.douban.com"]
start = 0
url = 'https://movie.douban.com/top250?start='
end = '&filter='
start_urls = [url + str(start) + end]
def parse(self, response):
item = DoubanspiderItem()
movies = response.xpath("//div[@class=\'info\']")
for each in movies:
title = each.xpath('div[@class="hd"]/a/span[@class="tit
le"]/text()').extract()
content = each.xpath('div[@class="bd"]/p/text()').extra
ct()
score = each.xpath('div[@class="bd"]/div[@class="star"]
/span[@class="rating_num"]/text()').extract()
info = each.xpath('div[@class="bd"]/p[@class="quote"]/s
pan/text()').extract()
item['title'] = title[0]
# 以;作为分隔，将 content 列表⾥所有元素合并成⼀个新的字符
串
item['content'] = ';'.join(content)
item['score'] = score[0]
item['info'] = info[0] # 提交 item
yield item
if self.start <= 225:
self.start += 25
yield scrapy.Request(self.url + str(self.start) + self.
end, callback=self.parse)

3、pipelines.py

from scrapy.conf import settings
import pymongo
class DoubanspiderPipeline(object):
def init (self): # 获取 setting 主机名、端⼝号和数据库
名 host = settings['MONGODB_HOST']
port = settings['MONGODB_PORT']
dbname = settings['MONGODB_DBNAME'] # pymongo.MongoClient(host, port) 创建 MongoDB 链接
client = pymongo.MongoClient(host=host,port=port)
# 指向指定的数据库
mdb = client[dbname]
# 获取数据库⾥存放数据的表名
self.post = mdb[settings['MONGODB_DOCNAME']]
def process_item(self, item, spider):
data = dict(item)
# 向指定的表⾥添加数据
self.post.insert(data)
return item

4、settings.py

BOT_NAME = 'doubanSpider'
SPIDER_MODULES = ['doubanSpider.spiders']
NEWSPIDER_MODULE = 'doubanSpider.spiders'
ITEM_PIPELINES = {
'doubanSpider.pipelines.DoubanspiderPipeline' : 300
} # Crawl responsibly by identifying yourself (and your website) on t
he user-agent
USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) Apple
WebKit/537.36 (KHTML, like Gecko) Chrome/48.0.2564.116 Safari/537.3
6'
# MONGODB 主机环回地址 127.0.0.1
MONGODB_HOST = '127.0.0.1'
# 端⼝号，默认是 27017
MONGODB_PORT = 27017
# 设置数据库名称
MONGODB_DBNAME = 'DouBan'
# 存放本次数据的表名称
MONGODB_DOCNAME = 'DouBanMovies'

5、运⾏

启动 MongoDB 数据库需要两个命令：
mongod：是 mongoDB 数据库进程本身
mongo：是命令⾏shell 客户端
sudo mongod # ⾸先启动数据库服务，再执⾏Scrapy
sudo mongo # 启动数据库 shell
在 mongo shell 下使⽤命令: # 查看当前数据库
> db
# 列出所有的数据库
> show dbs
# 连接 DouBan 数据库
> use DouBan
# 列出所有表
> show collections
# 查看表⾥的数据
> db.DouBanMoives.find()

#复制并访问链接：https://item.taobao.com/item.htm?spm=a2oq0.12575281.0.0.4ace1deb26SVlT&ft=t&id=619117901939
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