线程池的使用

三里屯摇滚

线程池的使用

1、通过创建一个拥有固定数目的线程的线程池
2、每次启动指定数目线程去执行任务，把线程的创建、维护交给线程池来管理
3、将多线程任务设置到定时任务中，观察线程执行情况

＝＝＝＝＝＝＝＝＝＝＝＝＝＝
如果不采用线程池，在我机器上运行大概35秒钟，程序就挂了！！！

1. package threads;
   
2. 
   
3. import java.util.ArrayList;
   
4. import java.util.List;
   
5. import java.util.Timer;
   
6. import java.util.TimerTask;
   
7. import java.util.concurrent.ExecutorService;
   
8. import java.util.concurrent.Executors;
   
9. 
   
10. /**
    
11. * 线程池测试
    
12. *
    
13. * @author liuwei
    
14. */
    
15. public class TestThreadPool extends TimerTask
    
16. {
    
17. 
    
18. private List<TestBean> initData = new ArrayList<TestBean>();
    
19. 
    
20. private ExecutorService services = null;
    
21. 
    
22. private final int threadNum = 1000;
    
23. 
    
24. private final int cycleNum = 80;
    
25. 
    
26. // 初始化数据及线程池
    
27. public TestThreadPool()
    
28. {
    
29. int n = threadNum * 2 + 3;
    
30. int c = 1;
    
31. for (int i = 1; i <= n; i++)
    
32. {
    
33. initData.add(new TestBean(cycleNum, String.valueOf(c)));
    
34. c++;
    
35. }
    
36. 
    
37. // 查看系统cpu个数
    
38. // int cpuNum = Runtime.getRuntime().availableProcessors();
    
39. // System.out.println("cpu number : " + cpuNum);
    
40. services = Executors.newFixedThreadPool(threadNum);
    
41. }
    
42. 
    
43. /**
    
44. * 需要多线程执行的方法
    
45. *
    
46. * @param obj
    
47. */
    
48. public void toPrint(TestBean obj)
    
49. {
    
50. if (null == obj)
    
51. {
    
52. return;
    
53. }
    
54. 
    
55. int n = obj.getN();
    
56. for (int i = 0; i < n; i++)
    
57. {
    
58. try
    
59. {
    
60. Thread.sleep(200);
    
61. } catch (InterruptedException e)
    
62. {
    
63. // TODO Auto-generated catch block
    
64. e.printStackTrace();
    
65. }
    
66. System.out.println("============" + Thread.currentThread().getName() + ", str : " + obj.getStr());
    
67. }
    
68. } // toPrint
    
69. 
    
70. // 执行线程方法的线程类
    
71. private class TestRun implements Runnable
    
72. {
    
73. private TestBean obj;
    
74. 
    
75. public TestRun(TestBean obj)
    
76. {
    
77. this.obj = obj;
    
78. }
    
79. 
    
80. public void run()
    
81. {
    
82. toPrint(obj);
    
83. }
    
84. } // TestRun
    
85. 
    
86. 
    
87. public void run()
    
88. {
    
89. int size = initData.size();
    
90. int count = (size + threadNum - 1) / threadNum;
    
91. System.out.println("count: " + count);
    
92. for (int i = 0; i < count; i++)
    
93. {
    
94. System.out.println("====================" + i);
    
95. for (int j = 0; j < threadNum; j++)
    
96. {
    
97. int index = i * threadNum + j;
    
98. // System.out.println("index: "+index);
    
99. if (index >= size)
    
100. {
     
101. break;
     
102. }
     
103. final TestBean obj = initData.get(i * threadNum + j);
     
104. // System.out.println(obj.getN());
     
105. // new Thread(new TestRun(obj)).start();
     
106. services.execute(new TestRun(obj));
     
107. 
     
108. }
     
109. 
     
110. } // end-for-initData
     
111. 
     
112. } // run
     
113. 
     
114. 
     
115. /**
     
116. * @param args
     
117. */
     
118. public static void main(String[] args)
     
119. {
     
120. // TODO Auto-generated method stub
     
121. Timer timer = new Timer();
     
122. TestThreadPool tt = new TestThreadPool();
     
123. // 启动后立即执行，每隔15秒钟在执行一次
     
124. timer.schedule(tt, 0, 15 * 1000);
     
125. 
     
126. // 关闭线程池
     
127. // tt.services.shutdown();
     
128. }
     
129. 
     
130. } // TestThreadPool
     
131. 
     
132. 
     
133. class TestBean
     
134. {
     
135. private int n;
     
136. private String str;
     
137. 
     
138. public TestBean(int n, String str)
     
139. {
     
140. this.n = n;
     
141. this.str = str;
     
142. }
     
143. 
     
144. public int getN()
     
145. {
     
146. return n;
     
147. }
     
148. 
     
149. public void setN(int n)
     
150. {
     
151. this.n = n;
     
152. }
     
153. 
     
154. public String getStr()
     
155. {
     
156. return str;
     
157. }
     
158. 
     
159. public void setStr(String str)
     
160. {
     
161. this.str = str;
     
162. }
     
163. } // TestBean

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