python爬取动态网页

静态网页：根据url即可方便的爬取

动态网页：分为两种：一种是通过F12查看控制台的xhr等文件，找到包含所要爬取的内容的文件，发现这个文件的url路径跟页码有联系，那么就可以根据构造的url来进行访问爬取了。还有一种情况是查看了包含所要爬取内容的文件，发现文件url是固定不变的或者跟页码没有关系，这个时候可以通过简单的模拟浏览器点击行为来请求网页再爬取，这种方案执行效率较慢，不适于多页爬取的情况。代码如下：

 1 def parse(self, response):
 2     print 'parser>>>>>>>>>>>>>>>'
 3     try:
 4         self.varint = 1
 5         while self.varint <= 100:
 6             url = self.ROOT_URL + '*' + str(self.varint) 
 7             responsenow = requests.get(url)
 8             self.parser_html(responsenow)
 9             self.varint = self.varint + 1
10             # time.sleep(0.1)
11         print('success>>>>>>>>>>>>')
12     except:
13         print('failed>>>>>>>>>')

对于动态网页，还可以通过模拟客户端发送post请求来爬取，代码如下：

def parse(self, response):
    formdata = {
        'pageNo': '',
        'categoryId': '',
        'code': '',
        'pageSize': 10,
        'source': '',
        'requestUri': '*',
        'requestMethod': 'POST'
    }
    print 'parser>>>>>>>>>>>>>>>'
    try:
        self.varint = 1
        formdata['source'] = str(2)
        formdata['pageNo'] = str(self.varint)
        while self.varint <= 46:
            responsenow = requests.post(self.ROOT_URL, data=formdata)
            self.parser_html(responsenow)
            self.varint = self.varint + 1
            formdata['source'] = formdata['pageNo']   
            formdata['pageNo'] = str(self.varint)
        print('success>>>>>>>>>>>>')
    except:
        print('failed>>>>>>>>>')