java 多线程小练

package org.wyq.test;

public class MyTest {

	public static void main(String[] args) {

		Bridge bridge = new Bridge();
		Person[] nperson = new Person[12]; // 站在北边的人
		Person[] sperson = new Person[10]; // 站在南边的人

		for (int i = 0; i < nperson.length; i++) {
			nperson[i] = new Person("np" + i, bridge, -1);
			nperson[i].start();
		}
		for (int i = 0; i < nperson.length; i++) {
			nperson[i] = new Person("sp" + i, bridge, 1);
			nperson[i].start();
		}
	}
}

/**
 * 人
 */
class Person extends Thread {
	private String name;
	private Bridge bridge;
	private int flag;;

	public Person() {
	}

	public Person(String name, Bridge bridge, int flag) {
		this.name = name;
		this.bridge = bridge;
		this.flag = flag;
	}

	public void run() {
		crossBridge();
	}

	/**
	 * 过桥
	 */
	public void crossBridge() {

		synchronized (bridge) {
			System.out.print(name + " 从" + (flag > 0 ? "南" : "北") + "面过桥");
			try {
				Thread.sleep(500); // 过桥使用500ms
			} catch (InterruptedException e) {
			}
			System.out.println("\t\t到达" + (flag > 0 ? "北" : "南") + "面");
		}

	}
}

/**
 * 桥
 */
class Bridge {
}

class Person extends Thread {
	private String name;
	private Bridge bridge; 
	private int flag;;

class Person extends Thread {
	private String name;
	private Bridge bridge; 
	private int flag;;

// 从面向对象的角度来说，桥不是人的一个属性，所以应该把Bridge属性去掉。
// 那么，下面的同步块种就应该这样写：
synchronized (Bridge.class) {
			// ...
		}