制作Scrapy爬虫和crawlspider爬整栈数据_execute(['scrapy','crawl','zhongguoxinwen'])

制作scrapy爬虫一共需要4步：

1.新建项目（scrapy startproject xxx)：新建一个新的爬虫项目

2.明确目标（编写items.py）：明确你想要抓取的目标

3.制作爬虫（xxspider.py）：制作爬虫开始爬取网页

4.存储内容（pipelines.py):设计管道存储爬取内容

爬虫顺序：main.py--->items/py-->xxspider.py-->settings.py-->pipelines.py

main.py是用于运行爬虫代码的，一般格式为：

from scrapy.cmdline import execute
import sys,os
 
 
sys.path.append(os.path.dirname(os.path.abspath(__file__)))
# execute(['scrapy','crawl','sun'])
execute(['scrapy','crawl','你的爬虫名'])

 若你爬取了图片，可在settings.py里自定义设置图片保存路径

在管道文件里可获取setting信息

 

在提crawlspider之前说一下正则表达式的有个方法

re.sub(s1,s2,s3)      将s3里所有s1替换成s2

和自增10一样

 

Crawlspider

通过scrapy genspider -t crawl  xxx  xxxxxx.com可快速创建crawlspider模块的代码

在xxx.py文件里要导入：

1.

from scrapy.linkextractors import LinkExtractor     

就是取网页里的链接

2

from scrapy.spiders import CrawlSpider, Rule

调用里面的两个函数来处理链接

3.实现

#Rule和LinkExtractor放到一起写了.allow是匹配符合的,deny是匹配出不符合的,没有回调函数follow=True,就跟进链接
rules = (
    #跟进第一页,第二页...
    Rule(LinkExtractor(allow=r'type=4&page=\d+')),
    #有回调函数follow=False,就不跟进,利用回调函数来处理.这里的回调函数不能加(),必须得用双引号引起来
    Rule(LinkExtractor(allow=r'/html/question/\d+/\d+.shtml'), callback = 'parse_item'),
)

注意用crawlspider后解析函数就不能命名为parse，用其他任何的代替都行

response.url就可以取网址          follow=True  跟进       

allow是匹配符合的,deny是匹配出不符合的

有回调函数follow=False,就不跟进,利用回调函数来处理.这里的回调函数不能加(),必须得用双引号引起来

没有回调函数follow=True,就跟进链接

Rule自带process_links方法,用来过滤数据  ， deal_links则是用来过滤数据的函数，要自定义

Rule(pagelink, process_links = "deal_links")

 

付一个爬取阳光热线问政平台的代码

main:

from scrapy.cmdline import execute
import sys,os
 
 
sys.path.append(os.path.dirname(os.path.abspath(__file__)))
# execute(['scrapy','crawl','sun'])
execute(['scrapy','crawl','dongdong'])

 

items:

# -*- coding: utf-8 -*-
 
# Define here the models for your scraped items
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/items.html
 
import scrapy
 
 
class DongguanItem(scrapy.Item):
    # define the fields for your item here like:
    title = scrapy.Field()
    content = scrapy.Field()
    url = scrapy.Field()
    number = scrapy.Field()

 

xxx:

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from dongguan.items import DongguanItem
 
#爬整栈用到crawlspider   注意解析网页
class DongdongSpider(CrawlSpider):
    name = 'dongdong'
    allowed_domains = ['wz.sun0769.com']
    start_urls = ['http://wz.sun0769.com/index.php/question/questionType?type=4&page=']
 
    # 每一页的匹配规则
    pagelink = LinkExtractor(allow=("type=4"))
    # 每一页里的每个帖子的匹配规则
    contentlink = LinkExtractor(allow=(r"/html/question/\d+/\d+.shtml"))
 
    rules = (
        # url被web服务器篡改，需要调用process_links来处理提取出来的url
        #process_links是自带 的方法,用来过滤数据
        Rule(pagelink, process_links = "deal_links"),
        Rule(contentlink, callback = "parse_item")
    )
 
    # links 是当前response里提取出来的链接列表
    def deal_links(self, links):
        for each in links:
            each.url = each.url.replace("?","&").replace("Type&","Type?")
        return links
 
    def parse_item(self, response):
        item = DongguanItem()
        # 标题
        item['title'] = response.xpath('//div[contains(@class, "pagecenter p3")]//strong/text()').extract()[0]
        # 编号
        item['number'] = item['title'].split(' ')[-1].split(":")[-1]
        # 内容，先使用有图片情况下的匹配规则，如果有内容，返回所有内容的列表集合
        content = response.xpath('//div[@class="contentext"]/text()').extract()
        # 如果没有内容，则返回空列表，则使用无图片情况下的匹配规则
        if len(content) == 0:
            content = response.xpath('//div[@class="c1 text14_2"]/text()').extract()
            item['content'] = "".join(content).strip()
        else:
            item['content'] = "".join(content).strip()
        # 链接
        item['url'] = response.url
 
        yield item

 

setting:

# -*- coding: utf-8 -*-
 
# Scrapy settings for dongguan project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://doc.scrapy.org/en/latest/topics/settings.html
#     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://doc.scrapy.org/en/latest/topics/spider-middleware.html
 
BOT_NAME = 'dongguan'
 
SPIDER_MODULES = ['dongguan.spiders']
NEWSPIDER_MODULE = 'dongguan.spiders'
 
 
# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'dongguan (+http://www.yourdomain.com)'
 
# Obey robots.txt rules
# ROBOTSTXT_OBEY = True
 
# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32
 
# Configure a delay for requests for the same website (default: 0)
# See https://doc.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16
 
# Disable cookies (enabled by default)
#COOKIES_ENABLED = False
 
# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False
 
# Override the default request headers:
DEFAULT_REQUEST_HEADERS = {
    'User-Agent': 'Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0);'
 
    # 'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
  # 'Accept-Language': 'en',
}
 
# Enable or disable spider middlewares
# See https://doc.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'dongguan.middlewares.DongguanSpiderMiddleware': 543,
#}
 
# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'dongguan.middlewares.DongguanDownloaderMiddleware': 543,
#}
 
# Enable or disable extensions
# See https://doc.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}
 
# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
    'dongguan.pipelines.DongguanPipeline': 300,
}
 
# Enable and configure the AutoThrottle extension (disabled by default)
# See https://doc.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False
 
# Enable and configure HTTP caching (disabled by default)
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

 

 pipelines:

# -*- coding: utf-8 -*-
 
# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html
 
 
import json
 
class DongguanPipeline(object):
    def __init__(self):
        self.filename = open("dongguan.json", "wb+")
 
    def process_item(self, item, spider):
        text = json.dumps(dict(item), ensure_ascii = False) + ",\n"
        self.filename.write(text.encode("utf-8"))
        return item
 
    def close_spider(self, spider):
        self.filename.close()