python爬虫----（6. scrapy框架，抓取亚马逊数据）

amazon
├── amazon
│   ├── __init__.py
│   ├── __init__.pyc
│   ├── items.py
│   ├── items.pyc
│   ├── msic
│   │   ├── __init__.py
│   │   └── pad_urls.py
│   ├── pipelines.py
│   ├── settings.py
│   ├── settings.pyc
│   └── spiders
│       ├── __init__.py
│       ├── __init__.pyc
│       ├── pad_spider.py
│       └── pad_spider.pyc
├── pad.xml
└── scrapy.cfg

from scrapy import Item, Field


class PadItem(Item):
    sno = Field()
    price = Field()

# -*- coding: utf-8 -*-
from scrapy import Spider, Selector
from scrapy.http import Request
from amazon.items import PadItem


class PadSpider(Spider):
    name = "pad"
    allowed_domains = ["amazon.com"]

    start_urls = []
    u1 = 'http://www.amazon.cn/s/ref=sr_pg_'
    u2 = '?rh=n%3A2016116051%2Cn%3A!2016117051%2Cn%3A888465051%2Cn%3A106200071&page='
    u3 = '&ie=UTF8&qid=1408641827'
    for i in range(181):
        url = u1 + str(i+1) + u2 + str(i+1) + u3
        start_urls.append(url)

    def parse(self, response):
        sel = Selector(response)
        sites = sel.xpath('//div[@class="rsltGrid prod celwidget"]')
        items = []
        for site in sites:
            item = PadItem()
            item['sno'] = site.xpath('@name').extract()[0]
            try:
                item['price'] = site.xpath('ul/li/div/a/span/text()').extract()[0]
            # 索引异常，说明是新品
            except IndexError:
                item['price'] = site.xpath('ul/li/a/span/text()').extract()[0]
            items.append(item)
        return items

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

# Scrapy settings for amazon project
#
# For simplicity, this file contains only the most important settings by
# default. All the other settings are documented here:
#
#     http://doc.scrapy.org/en/latest/topics/settings.html
#

BOT_NAME = 'amazon'

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

# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'amazon (+http://www.yourdomain.com)'

USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/536.5 (KHTML, like Gecko) Chrome/19.0.1084.54 Safari/536.5'

FEED_URI = 'pad.xml'
FEED_FORMAT = 'xml'

<?xml version="1.0" encoding="utf-8"?>
<items>
    <item>
        <sno>B00JWCIJ78</sno>
        <price>￥3199.00</price>
    </item>
    <item>
        <sno>B00E907DKM</sno>
        <price>￥3079.00</price>
    </item>
    <item>
        <sno>B00L8R7HKA</sno>
        <price>￥3679.00</price>
    </item>
    <item>
        <sno>B00IZ8W4F8</sno>
        <price>￥3399.00</price>
    </item>
    <item>
        <sno>B00MJMW4BU</sno>
        <price>￥4399.00</price>
    </item>
    <item>
        <sno>B00HV7KAMI</sno>
        <price>￥3799.00</price>
    </item>
    ...
</items>