Queue python线程间数据通讯的法宝

http://blog.csdn.net/crazy_fire/article/details/7506239

  Queue是标准模块所以可以直接import，用起来就像是个真正的队列，先进先出的原则，这样进程间就可以用这个数据了，丫丫的，这个可好了。还是那个经典的生产者和消费者关系开始吧，书上讲的不通俗，记得记得学MFC时候那个孙鑫就介绍的比较容易接受。好了，切入主题。

   有一个生产线，一个消费线，那么我们要做的就是消费的不能比生产的要多。脚本如下：

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1. #!/usr/bin/env python
   
2. 
   
3. '''
   
4. Created on Apr 25, 2012
   
5. 
   
6. @author: stedy
   
7. '''
   
8. #coding=cp936
   
9. from random import randint
   
10. from time import sleep,ctime
    
11. from Queue import Queue
    
12. import threading
    
13.      
    
14. class MyThread(threading.Thread):
    
15.     def __init__(self,func,args,name=""):
    
16.         threading.Thread.__init__(self)
    
17.         self.name = name
    
18.         self.func = func
    
19.         self.args = args
    
20.     def getResult(self):
    
21.         return self.res
    
22.     def run(self):
    
23.         print 'stating',self.name,'at',ctime()
    
24.         self.func(*self.args)
    
25.         
    
26. def writeQ(queue):
    
27.     i = randint(1,100)
    
28.     print 'producing object for Q...',queue.put(i,1)
    
29.         
    
30. def readQ(queue):
    
31.     if queue.empty() == False:
    
32.         val = queue.get(1)
    
33.         print 'value from Q',val
    
34.     else:
    
35.         print "no value,wait a moment"
    
36.         sleep(1)
    
37.            
    
38.      
    
39. def writer(queue,loops):
    
40.     for i in range(loops):
    
41.         writeQ(queue)
    
42.         sleep(randint(1,3))
    
43.      
    
44. def reader(queue,loops):
    
45.     for i in range(loops):
    
46.         readQ(queue)
    
47.         sleep(randint(1,3))
    
48.      
    
49. funcs = [reader,writer]
    
50. nfuncs = range(len(funcs))
    
51.      
    
52. def main():
    
53.     nloops = 99
    
54.     q = Queue(100)
    
55.        
    
56.     threads = []
    
57.     for i in nfuncs:
    
58.         t = MyThread(funcs[i],(q,nloops),funcs[i].__name__)
    
59.         threads.append(t)
    
60.     
    
61.     for i in nfuncs:
    
62.         threads[i].start()
    
63.        
    
64.     for i in nfuncs:
    
65.         threads[i].join()
    
66.     print 'all Done'
    
67.      
    
68. if __name__ == '__main__':
    
69.     main()

运行结果

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1. stating reader at Wed Apr 25 21:55:03 2012
   
2. no value,wait a moment
   
3. stating writer at Wed Apr 25 21:55:03 2012
   
4. producing object for Q... None
   
5. value from Q 65
   
6. producing object for Q... None
   
7. value from Q 94
   
8. producing object for Q... None
   
9. producing object for Q... None
   
10. value from Q 80
    
11. producing object for Q... None
    
12. value from Q 6
    
13. producing object for Q... None
    
14. value from Q 17
    
15. producing object for Q... None
    
16. producing object for Q... None
    
17. value from Q 11
    
18. producing object for Q... None
    
19. value from Q 33
    
20. producing object for Q... None
    
21. value from Q 46
    
22. producing object for Q... None
    
23. producing object for Q... None
    
24. producing object for Q... None
    
25. value from Q 14
    
26. value from Q 13
    
27. producing object for Q... None
    
28. value from Q 47
    
29. producing object for Q... None
    
30. value from Q 50
    
31. producing object for Q... None
    
32. value from Q 54
    
33. producing object for Q... None
    
34. producing object for Q... None
    
35. value from Q 17
    
36. producing object for Q... None
    
37. producing object for Q... None
    
38. value from Q 44
    
39. value from Qproducing object for Q... None
    
40.  26
    
41. producing object for Q... None
    
42. value from Q 77
    
43. producing object for Q... None
    
44. value from Q 38
    
45. producing object for Q... None
    
46. value from Q 14
    
47. value from Q 29
    
48. producing object for Q... None
    
49. value from Q 58
    
50. producing object for Q... None
    
51. value from Q 71
    
52. producing object for Q... None
    
53. value from Q 47
    
54. producing object for Q... None
    
55. value from Q 70
    
56. producing object for Q... None
    
57. value from Q 69
    
58. producing object for Q...value from Q 20
    
59. None
    
60. producing object for Q... None
    
61. value from Q 22
    
62. producing object for Q... None
    
63. value from Q 96
    
64. producing object for Q... None
    
65. producing object for Q...value from Q 52None
    
66. 
    
67. value from Q 63
    
68. producing object for Q... None
    
69. value from Q 79
    
70. producing object for Q... None
    
71. value from Q 99
    
72. value from Q 6
    
73. producing object for Q... None
    
74. value from Q 36
    
75. producing object for Q... None
    
76. value from Q 64
    
77. producing object for Q... None
    
78. value from Q 26
    
79. producing object for Q... None
    
80. value from Q 37
    
81. producing object for Q... None
    
82. value from Q 13
    
83. producing object for Q... None
    
84. value from Q 41
    
85. producing object for Q... None
    
86. value from Q 20
    
87. producing object for Q... None
    
88. value from Q 33
    
89. value from Q 26
    
90. producing object for Q... None
    
91. value from Q 21
    
92. producing object for Q... None
    
93. value from Q 50
    
94. value from Q 33
    
95. producing object for Q... None
    
96. value from Q 45
    
97. producing object for Q... None
    
98. value from Q 31
    
99. producing object for Q... None
    
100. producing object for Q... None
     
101. value from Q 39
     
102. producing object for Q... None
     
103. value from Q 90
     
104. producing object for Q... None
     
105. producing object for Q... None
     
106. value from Q 78
     
107. producing object for Q... None
     
108. producing object for Q... None
     
109. value from Q 84
     
110. producing object for Q... None
     
111. producing object for Q... None
     
112. value from Q 44
     
113. producing object for Q... None
     
114. value from Q 78
     
115. value from Q 17
     
116. producing object for Q... None
     
117. value from Q 7
     
118. value from Q 7
     
119. producing object for Q... None
     
120. value from Q 41
     
121. value from Q 71
     
122. producing object for Q... None
     
123. value from Q 57
     
124. producing object for Q... None
     
125. value from Q 65
     
126. producing object for Q... None
     
127. value from Q 12
     
128. value from Q 1
     
129. producing object for Q... None
     
130. producing object for Q... None
     
131. value from Q 97
     
132. value from Q 65
     
133. producing object for Q... None
     
134. value from Q 48
     
135. producing object for Q... None
     
136. producing object for Q... None
     
137. value from Q 1
     
138. producing object for Q... None
     
139. value from Q 58
     
140. value from Q 62
     
141. producing object for Q... None
     
142. value from Q 91
     
143. producing object for Q... None
     
144. value from Q 87
     
145. producing object for Q... None
     
146. value from Q 92
     
147. producing object for Q... None
     
148. value from Q 23
     
149. value from Q 15
     
150. producing object for Q... None
     
151. producing object for Q... None
     
152. value from Q 77
     
153. producing object for Q... None
     
154. producing object for Q... None
     
155. value from Q 3
     
156. value from Q 33
     
157. producing object for Q... None
     
158. producing object for Q... None
     
159. value from Q 87
     
160. producing object for Q... None
     
161. value from Q 94
     
162. producing object for Q... None
     
163. producing object for Q... None
     
164. value from Q 89
     
165. producing object for Q... None
     
166. value from Q 48
     
167. producing object for Q... None
     
168. producing object for Q... None
     
169. value from Q 65
     
170. producing object for Q... None
     
171. value from Q 55
     
172. producing object for Q... None
     
173. producing object for Q... None
     
174. value from Q 28
     
175. producing object for Q... None
     
176. producing object for Q... None
     
177. value from Q 61
     
178. producing object for Q... None
     
179. value from Q 47
     
180. producing object for Q... None
     
181. value from Q 16
     
182. producing object for Q... None
     
183. value from Q 77
     
184. producing object for Q... None
     
185. value from Q 86
     
186. producing object for Q... None
     
187. value from Q 39
     
188. value from Q 20
     
189. producing object for Q... None
     
190. value from Q 63
     
191. value from Q 13
     
192. producing object for Q... None
     
193. producing object for Q... None
     
194. value from Q 57
     
195. producing object for Q... None
     
196. value from Q 12
     
197. value from Q 9
     
198. value from Q 42
     
199. value from Q 70
     
200. value from Q 65
     
201. all Done

我们提取Queue的部分来看，首先是创建一个队列这是一个全局变量，当然是main内的’全局‘，这个变量给谁用呢？当然是给各个线程的函数用了，这里的数据就是能够共享的数据。

    存入数据的函数是put简单吧，直接把数据给放入进去，取出的就是get也简单啊，不管你在函数的什么地方用都可以看到这两个函数那么我们开始担心的问题其实用这连个函数就可以搞定了，就是如果消费的数量多于生产的数量，put(value,block=0)如果我们将第二个参数设置不为0的数据，那么函数就等待到队列中有空间为止，那样线程不就挂起了吗，所以生产商就有时间生产了啊，同样如果get(block=0)函数如果参数不为0同样的等待队列有数据时候才退出。呵呵，这模样，队列这个东西很好用啊