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线程基础---wait(),notify的应用一例
摘要: 线程基础---wait(),notify的应用一例
本例子实现了两个线程，每个线程输出1到100的数字。
第一个线程输出1-10，停止，通知第二个线程 输出1-10 第二个线程停止 通知第一个线程 输出11-20 ...
实现的要点是
在Java中，每个对象都有个对象锁标志(Object lock flag)与之想关联，当一个线程A调用对象的一段synchronized代码时，
它首先要获取与这个对象关联的对象锁标志，然后执行相应的代码，执行结束后，把这个对象锁标志返回给对象；因此，在线程A执行
synchronized代码期间，如果另一个线程B也要执行同一对象的一段synchronized代码时（不一定与线程A执行的相同），它将
要等到线程A执行完后，才能继续....
如何利用wait() notify() notifyAll()?
在synchronized代码被执行期间，线程可以调用对象的wait()方法，释放对象锁标志，进入等待状态，并且可以调用notify()或者
notifyAll()方法通知正在等待的其他线程。notify()通知等待队列中的第一个线程，notifyAll()通知的是等待队列中的所有线程。
/**
* Title: Jasons's Java Projdect
* Copyright: Copyright (c) ChinaJavaLab
* Company: http://www.ChinaJavaLab.com
* @author jason jason@ChinaJavaLab.com
* @version 1.0
*/
import java.lang.Runnable;
import java.lang.Thread;
public class DemoThread implements Runnable{
public DemoThread() {
TestThread testthread1 = new TestThread(this,"1");
TestThread testthread2 = new TestThread(this,"2");
testthread2.start();
testthread1.start();
}
public static void main(String[] args) {
DemoThread demoThread1 = new DemoThread();
}
public void run(){
TestThread t = (TestThread) Thread.currentThread();
try{
if (!t.getName().equalsIgnoreCase("1")) {
synchronized(this) {
wait();
}
}
while(true){
System.out.println("@time in thread"+ t.getName()+ "="+ t.increaseTime());
if(t.getTime()%10 == 0) {
synchronized(this) {
System.out.println("****************************************");
notify();
if ( t.getTime()==100 ) break;
wait();
}
}
}
}catch(Exception e){e.printStackTrace();}
}
}
class TestThread extends Thread{
private int time = 0 ;
public TestThread(Runnable r,String name){
super(r,name);
}
public int getTime(){
return time;
}
public int increaseTime (){
return ++time;
}
}
程序运行结果：
C:\java>java DemoThread
@time in thread1=1
@time in thread1=2
@time in thread1=3
@time in thread1=4
@time in thread1=5
@time in thread1=6
@time in thread1=7
@time in thread1=8
@time in thread1=9
@time in thread1=10
****************************************
@time in thread2=1
@time in thread2=2
@time in thread2=3
@time in thread2=4
@time in thread2=5
@time in thread2=6
@time in thread2=7
@time in thread2=8
@time in thread2=9
@time in thread2=10
****************************************
@time in thread1=11
@time in thread1=12
@time in thread1=13
@time in thread1=14
@time in thread1=15
@time in thread1=16
@time in thread1=17
@time in thread1=18
@time in thread1=19
@time in thread1=20
****************************************
@time in thread2=11
@time in thread2=12
@time in thread2=13
@time in thread2=14
@time in thread2=15
@time in thread2=16
@time in thread2=17
@time in thread2=18
@time in thread2=19
@time in thread2=20
****************************************
@time in thread1=21
@time in thread1=22
@time in thread1=23
@time in thread1=24
@time in thread1=25
@time in thread1=26
@time in thread1=27
@time in thread1=28
@time in thread1=29
@time in thread1=30
****************************************
@time in thread2=21
@time in thread2=22
@time in thread2=23
@time in thread2=24
@time in thread2=25
@time in thread2=26
@time in thread2=27
@time in thread2=28
@time in thread2=29
@time in thread2=30
****************************************
@time in thread1=31
@time in thread1=32
@time in thread1=33
@time in thread1=34
@time in thread1=35
@time in thread1=36
@time in thread1=37
@time in thread1=38
@time in thread1=39
@time in thread1=40
****************************************
@time in thread2=31
@time in thread2=32
@time in thread2=33
@time in thread2=34
@time in thread2=35
@time in thread2=36
@time in thread2=37
@time in thread2=38
@time in thread2=39
@time in thread2=40
****************************************
@time in thread1=41
@time in thread1=42
@time in thread1=43
@time in thread1=44
@time in thread1=45
@time in thread1=46
@time in thread1=47
@time in thread1=48
@time in thread1=49
@time in thread1=50
****************************************
@time in thread2=41
@time in thread2=42
@time in thread2=43
@time in thread2=44
@time in thread2=45
@time in thread2=46
@time in thread2=47
@time in thread2=48
@time in thread2=49
@time in thread2=50
****************************************
@time in thread1=51
@time in thread1=52
@time in thread1=53
@time in thread1=54
@time in thread1=55
@time in thread1=56
@time in thread1=57
@time in thread1=58
@time in thread1=59
@time in thread1=60
****************************************
@time in thread2=51
@time in thread2=52
@time in thread2=53
@time in thread2=54
@time in thread2=55
@time in thread2=56
@time in thread2=57
@time in thread2=58
@time in thread2=59
@time in thread2=60
****************************************
@time in thread1=61
@time in thread1=62
@time in thread1=63
@time in thread1=64
@time in thread1=65
@time in thread1=66
@time in thread1=67
@time in thread1=68
@time in thread1=69
@time in thread1=70
****************************************
@time in thread2=61
@time in thread2=62
@time in thread2=63
@time in thread2=64
@time in thread2=65
@time in thread2=66
@time in thread2=67
@time in thread2=68
@time in thread2=69
@time in thread2=70
****************************************
@time in thread1=71
@time in thread1=72
@time in thread1=73
@time in thread1=74
@time in thread1=75
@time in thread1=76
@time in thread1=77
@time in thread1=78
@time in thread1=79
@time in thread1=80
****************************************
@time in thread2=71
@time in thread2=72
@time in thread2=73
@time in thread2=74
@time in thread2=75
@time in thread2=76
@time in thread2=77
@time in thread2=78
@time in thread2=79
@time in thread2=80
****************************************
@time in thread1=81
@time in thread1=82
@time in thread1=83
@time in thread1=84
@time in thread1=85
@time in thread1=86
@time in thread1=87
@time in thread1=88
@time in thread1=89
@time in thread1=90
****************************************
@time in thread2=81
@time in thread2=82
@time in thread2=83
@time in thread2=84
@time in thread2=85
@time in thread2=86
@time in thread2=87
@time in thread2=88
@time in thread2=89
@time in thread2=90
****************************************
@time in thread1=91
@time in thread1=92
@time in thread1=93
@time in thread1=94
@time in thread1=95
@time in thread1=96
@time in thread1=97
@time in thread1=98
@time in thread1=99
@time in thread1=100
****************************************
@time in thread2=91
@time in thread2=92
@time in thread2=93
@time in thread2=94
@time in thread2=95
@time in thread2=96
@time in thread2=97
@time in thread2=98
@time in thread2=99
@time in thread2=100
****************************************
C:\java>
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