python 多线程

Python中使用线程有两种方式：函数或者用类来包装线程对象。

 1 函数式：调用thread模块中的start_new_thread()函数来产生新线程。

 start_new_thread是实例化一个线程并运行的方法，方法的第一个参数接受一个线程运行时所执行的函数对象，第二个参数是方法执行时所需要的参数，以一个元组的形式传入。

import time  
import thread  
def timer(no, interval):  
    cnt = 0  
    while cnt<10:  
        print 'Thread:(%d)+ (%d)+ Time:%s\n'%(no,cnt,time.ctime())  
        time.sleep(interval)  
        cnt+=1  
    thread.exit_thread()  
     
   
def test(): #Use thread.start_new_thread() to create 2 new threads  
    thread.start_new_thread(timer, (1,1))  
    thread.start_new_thread(timer, (2,2))  
   
if __name__=='__main__':  
    test() 
    time.sleep(10) 

最后已经不加的话会包异常：

Unhandled exception in thread started by

Error in sys.excepthook:

Original exception was:

所以不推荐使用thread，推荐使用threading

根据log显示，出现报错的现象：

启动线程之后，必须调用time.sleep休眠足够长的时间，使主线程等待所有子线程返回结果，如果主线程比子线程早结束，就会抛出这个异常。

2  创建threading.Thread的子类来包装一个线程对象，如下例：

#! /usr/bin/env python
#coding=utf-8
from time import ctime,sleep  
import threading;  
from random import choice  
'''
def loop(number,sec):  
    print "Thread ",number," begins and will sleep ",sec," at ",ctime();  
    sleep(sec);  
    print "Thread ",number,"ends at ",ctime();  
      
def main():  
    seconds=[2,4];  
    threads=[];  
    array=range(len(seconds));  
    for i in array :  
        t=threading.Thread(target=loop,args=(i,choice(seconds)));  
        threads.append(t);  
    print "main Thread begins at ",ctime();  
    for t in threads :  
        t.start();  
    for t in threads :  
        t.join();          
    print "main Thread ends at ",ctime();  
  
if __name__=="__main__" :  
    main();
'''
'''
class ThreadFunc(object):  
    def __init__(self,func,args,name):  
        self.func=func;  
        self.args=args;  
        self.name=name;  
          
    def __call__(self):  
        self.func(*self.args);  
  
def loop(number,sec):  
    print "Thread ",number," begins and will sleep ",sec," at ",ctime();  
    sleep(sec);  
    print "Thread ",number,"ends at ",ctime();  
      
def main():  
    seconds=[2,4];  
    threads=[];  
    array=range(len(seconds));  
    for i in array :  
        t=threading.Thread(target=ThreadFunc(loop,(i,choice(seconds)),loop.__name__));  
        threads.append(t);  
    print "main Thread begins at ",ctime();  
    for t in threads :  
        t.start();  
    for t in threads :  
        t.join();          
    print "main Thread ends at ",ctime();  
  
if __name__=="__main__" :  
    main();  

'''
class MyThread(threading.Thread):  
    def __init__(self,func,args,name):  
        super(MyThread,self).__init__();  
        self.func=func;  
        self.args=args;  
        self.name=name;  
              
    def run(self):  
        self.result=self.func(*self.args);  
  
    def getResult(self):  
        return self.result;  
      
def loop(number,sec):  
    print "Thread ",number," begins and will sleep ",sec," at ",ctime();  
    sleep(sec);  
    print "Thread ",number,"ends at ",ctime();  
      
def main():  
    seconds=[2,4];  
    threads=[];  
    array=range(len(seconds));  
    for i in array :  
        t=MyThread(loop,(i,choice(seconds)),loop.__name__);  
        threads.append(t);  
    print "main Thread begins at ",ctime();  
    for t in threads :  
        t.start();  
    for t in threads :  
        t.join();          
    print "main Thread ends at ",ctime();  
  
if __name__=="__main__" :  
    main();  

从上面可以看出MyThread继承了threading.Thread类，并在初始化方法中执行了必要的参数赋值。值得注意的是在Java类的继承中，如果不显示的指定调用父类的构造方法，那么默认将调用父类的无参构造方法。而在Python中，就不会主动去调用。所以这里需要显示的调用父类的初始化方法。

参考：

http://bestchenwu.iteye.com/blog/1063401

http://www.cnblogs.com/hbycool/articles/2749975.html