python之scrapy篇(二)

一、创建工程

scarpy startproject xxx

二、编写iteam文件

# -*- coding: utf-8 -*-

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html

import scrapy

class TestScrapyItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    name = scrapy.Field()
    title = scrapy.Field()
    info = scrapy.Field()

二、编写setting文件

# -*- coding: utf-8 -*-

# Scrapy settings for test_scrapy project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'test_scrapy'

SPIDER_MODULES = ['test_scrapy.spiders']
NEWSPIDER_MODULE = 'test_scrapy.spiders'

# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'test_scrapy (+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://docs.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 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.87 Safari/537.36',
    'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
   # 'Accept-Language': 'en',
}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'test_scrapy.middlewares.TestScrapySpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'test_scrapy.middlewares.TestScrapyDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
   'test_scrapy.pipelines.TestScrapyPipeline': 300,
}

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.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://docs.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'

三、进入spider文件(cmd创建自定义爬虫文件)

scrapy genspider demo 'www.douyu.com'

编写代码

import scrapy
from test_scrapy.items import TestScrapyItem

class ItcastSpider(scrapy.Spider):
    # 爬虫名
    name = "itcast"
    # 允许爬虫作用的范围
    allowd_domains = ['http://www.xxxx.cn/']
    # 爬虫起始的url
    start_urls = ["http://www.xxxx.cn/channel/teacher.shtml#ajavaee"]

    def parse(self, response):
        # with open("teacher.html", "w") as f:
        #     f.write(response.body)
        # 通过自带的xpath匹配出所有老师的根节点列表集合
        teacher_list = response.xpath('//div[@class="li_txt"]')

        # 所有老师信息的列表集合
        # 遍历根节点集合
        for each in teacher_list:
            # 保存数据
            item = TestScrapyItem()
            # name,extract()将匹配出来的结果转换为unicode字符串
            # 不加extract()结果为xpath匹配对象
            name = each.xpath('./h3/text()').extract()
            # title
            title = each.xpath('./h4/text()').extract()
            # info
            info = each.xpath('./p/text()').extract()

            item['name'] = name[0]
            item['title'] = title[0]
            item['info'] = info[0]

            yield item

四、运行

scrapy crawl xxxx

OVER!