Python gevent协程发http请求

为什么要用协程，Python在执行并发任务时有：

• 多线程用锁，很容易造成数据不稳定,无法使用发挥多核CPU的能力
• 多进程耗资源

Python通过yield提供了对协程的基本支持，但是不完全。而第三方的gevent为Python提供了比较完善的协程支持。

• 安装gevent
• 安装： pip install greenlet

#-*- coding: utf-8 -*-
import urllib.request
# url = "http://r.qzone.qq.com/cgi-bin/user/cgi_personal_card?uin=******"
url = "http://gc.ditu.aliyun.com/geocoding?a="+urllib.request.quote("广州市")
HEADER = {'Accept':'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8','User-Agent':'Mozilla/5.0 (Windows NT 6.1; rv:29.0) Gecko/20100101 Firefox/29.0'}

# 自定义请求的方法,get post
def f(url):
    import urllib
    import urllib.request
    data=urllib.request.urlopen(url).read()
    z_data=data.decode('UTF-8')
    print(z_data)

# 我自己封装了gevent 的方法,重载了run
from gevent import Greenlet
class MyGreenlet(Greenlet):
    def __init__(self, func):
        Greenlet.__init__(self)
        self.func = func
    def _run(self):
        # gevent.sleep(self.n)
        self.func

        
count = 3
green_let = []
for i in range(0, count):
    green_let.append(MyGreenlet(f(url)))
for j in range(0, count):
    green_let[j].start()
for k in range(0, count):
    green_let[k].join() 

• 运行结果

C:\Python3\python.exe D:/app/dgm/field_study.py
{"lon":120.58531,"level":2,"address":"","cityName":"","alevel":4,"lat":31.29888}
{"lon":120.58531,"level":2,"address":"","cityName":"","alevel":4,"lat":31.29888}
{"lon":120.58531,"level":2,"address":"","cityName":"","alevel":4,"lat":31.29888}