scrapy爬虫案例：问政平台

import scrapy

class DongguanItem(scrapy.Item):
    # 每个帖子的标题
    title = scrapy.Field()
    # 每个帖子的编号
    number = scrapy.Field()
    # 每个帖子的文字内容
    content = scrapy.Field()
    # 每个帖子的url
    url = scrapy.Field()

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

import scrapy
from scrapy.spiders import CrawlSpider

from scrapyDemo.items import DongguanItem


class SunSpider(CrawlSpider):
    name = ‘sun‘
    allowed_domains = [‘wz.sun0769.com‘]
    url = ‘http://wz.sun0769.com/index.php/question/questionType?type=4&page=‘
    offset = 0
    start_urls = [url + str(offset)]

    def parse(self, response):
        # 取出每个页面里帖子链接列表
        links = response.xpath("//div[@class=‘greyframe‘]/table//td/a[@class=‘news14‘]/@href").extract()
        # 迭代发送每个帖子的请求，调用parse_item方法处理
        for link in links:
            yield scrapy.Request(link, callback=self.parse_item)
        # 设置页码终止条件，并且每次发送新的页面请求调用parse方法处理
        if self.offset <= 3876:
            self.offset += 30
            yield scrapy.Request(self.url + str(self.offset), callback=self.parse)

    # 处理每个帖子里
    def parse_item(self, response):
        item = DongguanItem()
        # 标题
        item[‘title‘] = response.xpath(‘//span[contains(@class, "niae2_top")]/text()‘).extract()[0]
 　　　　# 编号
        item[‘number‘] = response.xpath(‘//div[contains(@class, "wzy1")]//td//span/text()‘).extract()[1]
        # 文字内容，默认先取出有图片情况下的文字内容列表
        content = response.xpath(‘//td[@class="txt16_3"]/text()‘).extract()
        # 如果没有内容，则取出没有图片情况下的文字内容列表
        if len(content) == 0:
            content = response.xpath(‘//div[@class="c1 text14_2"]/text()‘).extract()
            # content为列表，通过join方法拼接为字符串，并去除首尾空格
            item[‘content‘] = "".join(content).strip()
        else:
            item[‘content‘] = "".join(content).strip()

        # 链接
        item[‘url‘] = response.url
        yield item

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

# 文件处理类库，可以指定编码格式
import codecs
import json

class DongguanPipeline(object):

    def __init__(self):
        # 创建一个只写文件，指定文本编码格式为utf-8
        self.filename = codecs.open(‘sunwz.json‘, ‘w‘, encoding=‘utf-8‘)

    def process_item(self, item, spider):
        content = json.dumps(dict(item), ensure_ascii=False) + "\n"
        self.filename.write(content)
        return item

    def spider_closed(self, spider):
        self.file.close()

ITEM_PIPELINES = {
    ‘dongguan.pipelines.DongguanPipeline‘: 300,
}

# 日志文件名和处理等级
LOG_FILE = "dg.log"
LOG_LEVEL = "DEBUG"

from scrapy import cmdline
cmdline.execute(‘scrapy crawl sunwz‘.split())

py2 main.py