1. 在项目文件夹中新建一个commands文件夹

2. 在command的文件夹中新建一个文件 crawlall.py

3.在crawlall.py 中写一个command类，该类继承 scrapy.commands

from scrapy.commands import ScrapyCommandclass Command(ScrapyCommand):    requires_project = True    def syntax(self):        return '[options]'    def short_desc(self):        return 'Runs all of the spiders'    def run(self, args, opts):        spider_list = self.crawler_process.spiders.list()        for name in spider_list:            self.crawler_process.crawl(name, **opts.__dict__)        self.crawler_process.start()

• 命令行执行:启动所有爬虫         scrapy crawlall