scrapy实战8关于数据异步写入mysql：

 1 from twisted.enterprise import adbapi
 2 import pymysql
 3 import pymysql.cursors
 4 
 5 
 6 class MysqlTwistedPipeline(object):
 7     def __init__(self,dbpool):
 8         self.dbpool=dbpool
 9 
10     @classmethod
11     def from_settings(cls,settings):
12         dbpool=adbapi.ConnectionPool("pymysql",host=settings["MYSQL_HOST"],db=settings["MYSQL_DBNAME"],user=settings["MYSQL_USER"],password=settings["MYSQL_PASSWORD"],charset="utf8", cursorclass=pymysql.cursors.DictCursor,
13             use_unicode=True)
14         return cls(dbpool)
15 
16     def process_item(self,item,spider):
17         # 使用twisted将mysql插入变成异步执行
18         self.dbpool.runInteraction(self.do_insert,item)
19 
20 
21     def do_insert(self,cursor,item):
22         # 执行具体的插入
23         # 根据不同的item 构建不同的sql语句并插入到mysql中
24         insert_sql, params = item.get_insert_sql()
25         cursor.execute(insert_sql, params)

 1 import scrapy
 2 
 3 
 4 class TencentItem(scrapy.Item):
 5    
 6     positionname=scrapy.Field()
 7     positionlink=scrapy.Field()
 8     positionType=scrapy.Field()
 9     positionNum=scrapy.Field()
10     positionLocation=scrapy.Field()
11     publishTime=scrapy.Field()
12 
13 
14     def get_insert_sql(self):
15         insert_sql="""
16         insert into tencent(positionname,positionlink,positionType,positionNum,positionLocation,publishTime)
17         VALUES (%s,%s,%s,%s,%s,%s)
18         
19         """
20         params=(
21             self[‘positionname‘], self[‘positionlink‘], self[‘positionType‘], self[‘positionNum‘],
22             self[‘positionLocation‘], self[‘publishTime‘]
23         )
24         return insert_sql,params
25     

BOT_NAME = ‘tencent‘

SPIDER_MODULES = [‘tencent.spiders‘]
NEWSPIDER_MODULE = ‘tencent.spiders‘


ROBOTSTXT_OBEY = False

（不用分布式可忽略下面三项）
SCHEDULER = "scrapy_redis.scheduler.Scheduler"
DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
SCHEDULER_PERSIST = True


DOWNLOAD_DELAY = 2

DEFAULT_REQUEST_HEADERS = {
  ‘User-Agent‘:‘Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:53.0) Gecko/20100101 Firefox/53.0‘,
  ‘Accept‘: ‘text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8‘,
   #‘Accept-Language‘: ‘en‘,
}


ITEM_PIPELINES = {
       ‘scrapy_redis.pipelines.RedisPipeline‘:400,（不用分布式可忽略）
      ‘tencent.pipelines.MysqlTwistedPipeline‘: 300,
}
REDIS_HOST = ‘172.21.118.56‘（分布式主机ip 不用分布式可忽略）
REDIS_PORT = 6379（不用分布式可忽略）


MYSQL_HOST = "127.0.0.1"
MYSQL_DBNAME = "tencent"(自己数据库名字）
MYSQL_USER = "usrername"（用户名）
MYSQL_PASSWORD = "userpassword"（密码）

from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import Rule
from scrapy_redis.spiders import RedisCrawlSpider
from tencent.items import TencentItem

class TencentSpider(RedisCrawlSpider):
    name = "Tencent"
    allowed_domains = ["tencent.com"]
    redis_key = ‘TencentSpider:start_urls‘


    page_link=LinkExtractor(allow=(r"start=\d+"))

    rules=[
            Rule(page_link,callback = "parseContent",follow=True)
    ]

    def parseContent(self, response):
        list=response.xpath(‘//tr[@class="even"] | //tr[@class="odd"]‘)
        for infos in list:
            item=TencentItem()
            item[‘positionname‘]=infos.xpath("./td[1]/a/text()").extract()[0]
            item[‘positionlink‘]=infos.xpath("./td[1]/a/@href").extract()[0]
            item[‘positionType‘]=infos.xpath("./td[2]/text()").extract()
            item[‘positionNum‘]=infos.xpath("./td[3]/text()").extract()[0]
            item[‘positionLocation‘]=infos.xpath("./td[4]/text()").extract()[0]
            item[‘publishTime‘]=infos.xpath("./td[5]/text()").extract()[0]

            yield item