#1. 可以控制多个任务之间的切换，切换之前将任务的状态保存下来，以便重新运行时，可以基于暂停的位置继续执行。
#2. 作为1的补充：可以检测io操作，在遇到io操作的情况下才发生切换

#代码如下，yield本质是保存现在的状态，send是调用其他函数
def pro():print(1)n = yield 'a'print(n)yield 'b'def com():g = pro()a = next(g)print(a)b = g.send(2)print(b)com()

#单纯的生产者，消费者模型
import timedef consumer(res):'''单纯的处理数据'''passdef producer():res =[]for i in range(10000000):passreturn resstart = time.time()
res = producer()
consumer(res)
end = time.time()
print(end-start)
#结果
0.347031831741333#用yield模式尝试import timedef consumer():while True:x = yielddef producer():g = consumer()next(g)for i in range(10000000):g.send(i)
start = time.time()
#并发的执行任务
producer()
end = time.time()print(end-start)#结果
1.8232519626617432

import greenletdef eat():print('eat1')g2.switch()print('eat2')g2.switch()def sleep():print('sleep1')g1.switch()print('sleep2')g1 = greenlet.greenlet(eat)
g2 = greenlet.greenlet(sleep)
g1.switch()
#结果
eat1
sleep1
eat2
sleep2

#gevent模块的使用方法
g1=gevent.spawn(func,1,,2,3,x=4,y=5)创建一个协程对象g1，spawn括号内第一个参数是函数名，如eat，后面可以有多个参数，可以是位置实参或关键字实参，都是传给函数eat的g2=gevent.spawn(func2)g1.join() #等待g1结束g2.join() #等待g2结束#或者上述两步合作一步：gevent.joinall([g1,g2])g1.value#拿到func1的返回值

import gevent
def eat():print('eat1')gevent.sleep(1)print('eat2')def sleep():print('sleep1')gevent.sleep(1)print('sleep2')
g1 = gevent.spawn(eat)#实例化一个gevent对象
g2 = gevent.spawn(sleep)#实例化一个gevent对象gevent.joinall([g1,g2])#监测到有I/O就切换

from gevent import monkey
monkey.patch_all()#用来匹配所有的I/O操作
import gevent
import time
def eat():print('eat1')time.sleep(1)print('eat2')def sleep():print('sleep1')time.sleep(1)print('sleep2')
g1 = gevent.spawn(eat)#实例化一个gevent对象
g2 = gevent.spawn(sleep)#实例化一个gevent对象gevent.joinall([g1,g2])#监测到有I/O就切换

from gevent import monkey
monkey.patch_all()
import gevent
import time
from threading import currentThreaddef eat():print('eat:',currentThread())print('eat1')time.sleep(1)print('eat2')def sleep():print('sleep:',currentThread())print('sleep1')time.sleep(1)print('sleep2')g1 = gevent.spawn(eat)
g2 = gevent.spawn(sleep)gevent.joinall([g1,g2])
#结果如下
eat: <_DummyThread(DummyThread-1, started daemon 53379528)>
eat1
sleep: <_DummyThread(DummyThread-2, started daemon 53380480)>
sleep1
eat2
sleep2

#普通打开方式
import time
from urllib import requestdef func(name,url):ret =  request.urlopen(url)#获取网页with open(name+'.html','wb') as f:f.write(ret.read())
url_lst = [('python','https://www.python.org/'),('blog','http://www.cnblogs.com/Eva-J/articles/8324673.html'),('pypi','https://pypi.org/project/pip/'),('blog2','https://www.cnblogs.com/z-x-y/p/9237706.html'),('douban','https://www.douban.com/')
]
start = time.time()
for url_item in url_lst:func(*url_item)
end = time.time()
print('普通打开方式',end-start)#协程打开方式
from gevent import monkey
monkey.patch_all()
import gevent
from urllib import request
import timedef func(name,url):ret = request.urlopen(url)with open(name+'2.html','wb')as f:f.write(ret.read())url_lst = [('python','https://www.python.org/'),('blog','http://www.cnblogs.com/Eva-J/articles/8324673.html'),('pypi','https://pypi.org/project/pip/'),('blog2','https://www.cnblogs.com/z-x-y/p/9237706.html'),('douban','https://www.douban.com/')
]
start = time.time()
g_list =[]
for url_item in url_lst:g = gevent.spawn(func,*url_item)g_list.append(g)
gevent.joinall(g_list)
end = time.time()
print('协程打开方式',end-start)

#服务端
import socket
from gevent import monkey
monkey.patch_all()
import geventdef talk(conn):while True:msg = conn.recv(1024).decode()conn.send(msg.upper().encode('utf-8'))sk =socket.socket()
sk.bind(('127.0.0.1',8500))
sk.listen()while True:conn,addr = sk.accept()gevent.spawn(talk,conn)

import socket
sk = socket.socket()
sk.connect(('127.0.0.1',8500))while True:msg = input('--->').encode('utf-8')sk.send(msg)recv_msg = sk.recv(1024).decode('utf-8')print(recv_msg)sk.close()