python并发模块之concurrent.futures(二)

上次我们简单的了解下，模块的一些基本方法和用法，这里我们进一步对concurrent.futures做一个了解和拓展.上次的内容点这。python并发模块之concurrent.futures(二)以下载图片为例子，下面的程序是顺序下载http://www.58pic.com/newpic/28660111.html网站的24个表情 。

from requests_html import HTMLSessionimport osimport timeBASE_PATH="downloads"class Get_Image():    def __init__(self):        self.timeout=20        self.session=HTMLSession()    def getiamge(self,url):        req=self.session.get(url,timeout=self.timeout)        if req.status_code==200:            imgurllist=req.html.xpath("//ul[@class='emoticon-model']/li/img/@data-big")            for index,url in enumerate(imgurllist):                print(f"开始下载第{index+1}张图片")                self.save_image(url,index+1)        else:            print("下载失败")    def save_image(self,imgurl,index):        print(f"当前下载链接：{imgurl}")        buff=self.session.get(imgurl,timeout=self.timeout).content        file_path=os.path.join(os.path.dirname(os.path.abspath(__file__)),BASE_PATH)        if not os.path.exists(file_path):            os.makedirs(file_path)        with open(os.path.join(file_path,f"{index}.png"),"wb") as fs:            fs.write(buff)if __name__ == '__main__':    start_url="http://www.58pic.com/newpic/28660111.html"    start=time.time()    Get_Image().getiamge(start_url)    end=time.time()    print(f"顺序下载24张图片用时:{end-start}")#运行了两次结果分别为#顺序下载24张图片用时:14.926000356674194#顺序下载24张图片用时:14.07800030708313

使用concurrent.futures修改成并发之后

from requests_html import HTMLSessionimport osimport timefrom concurrent.futures import ThreadPoolExecutorBASE_PATH="downloads"MAX_WORKERS = 10 #最多使用10个线程class Get_Image():    def __init__(self):        self.timeout=20        self.session=HTMLSession()    def getiamge(self,url):        req=self.session.get(url,timeout=self.timeout)        if req.status_code==200:            imgurllist=req.html.xpath("//ul[@class='emoticon-model']/li/img/@data-big")            works=min(len(imgurllist),MAX_WORKERS)            with ThreadPoolExecutor(works) as excutor:                res=excutor.map(self.save_image,imgurllist,range(1,25))            return len(list(res))        else:            print("下载失败")    def save_image(self,imgurl,index):        print(f"当前下载链接：{imgurl}")        buff=self.session.get(imgurl,timeout=self.timeout).content        file_path=os.path.join(os.path.dirname(os.path.abspath(__file__)),BASE_PATH)        if not os.path.exists(file_path):            os.makedirs(file_path)        with open(os.path.join(file_path,f"{index}.png"),"wb") as fs:            fs.write(buff)if __name__ == '__main__':    start_url="http://www.58pic.com/newpic/28660111.html"    start=time.time()    Get_Image().getiamge(start_url)    end=time.time()    print(f"并发下载24张图片用时:{end-start}")#运行了两次结果分别为#并发下载24张图片用时:7.737000226974487#并发下载24张图片用时:7.083999872207642

通过观察发现速度并发之后效率大大提高了。

转载于:https://www.cnblogs.com/c-x-a/p/9207907.html