代码语言：javascript复制
1 package com.thread.test.thread;
2
3 import java.util.Random;
4 import java.util.concurrent.*;
5
6 /**
7 * Semaphore
8 * Semaphore维护者一组权限，无实体权限，只是一组代表权限的数字，
9 * 每一次执行acquire都会被阻塞，直到获取获取权限，
10 * 每一次执行release都会释放权限，唤醒阻塞acquire线程
11 *
12 * Semaphore通常应用于限制资源访问
13 *
14 *
15 * Created by windwant on 2016/5/27.
16 */
17 public class MySemaphore {
18
19 public static void main(String[] args) {
20 Semaphore sp = new Semaphore(5, true); //公平性 构造函数 true
21 ExecutorService es = Executors.newCachedThreadPool();
22 Random r = new Random();
23 for (int i = 0; i < 10; i ){
24 es.execute(new Needer(sp, r.nextInt(10), "needer" i));
25 }
26 es.shutdown();
27 }
28 }
29
30 class Needer implements Runnable{
31
32 private Semaphore sp;
33
34 private int seconds;
35
36 private String neederName;
37
38 Needer(Semaphore sp, int seconds, String neederName){
39 this.sp = sp;
40 this.seconds = seconds;
41 this.neederName = neederName;
42 }
43
44 public void run() {
45 try{
46 sp.acquire();
47 System.out.println("needer " neederName " begin, need time: " seconds "s");
48 long b = System.currentTimeMillis();
49 for (int i = 0; i < seconds; i ) {
50 Thread.sleep(1000);
51 System.out.println("needer: " neederName "============" i "============");
52 }
53 long d = System.currentTimeMillis() - b;
54 System.out.println("needer " neederName " over, executing time: " TimeUnit.SECONDS.convert(d, TimeUnit.MILLISECONDS));
55 sp.release();
56 } catch (InterruptedException e) {
57 e.printStackTrace();
58 }
59 }
60 }项目地址：https://github.com/windwant/windwant-demo/tree/master/thread-demo
