一个synchronized,wait,notifyall的例子
package test;
public class ThreadTest {
public static void main(String[] args) {
Thread t1 = new Thread(new Runnable1());
Thread t2 = new Thread(new Runnable2());
t1.start();
t2.start() ;
try {
t1.join() ;
} catch (InterruptedException e) {
throw new RuntimeException(e.getMessage());
}
try {
t2.join() ;
} catch (InterruptedException e) {
throw new RuntimeException(e.getMessage());
}
System.out.println("at last:"+counter);
}
public static int counter = 0 ;
}
package test;
public class Runnable1 implements Runnable {
@Override
public void run() {
for (int i= 0 ; i < 1000000 ; i ++)
{
synchronized (ThreadTest.class) {
if (ThreadTest.counter > 0)
try {
ThreadTest.class.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e.getMessage());
}
ThreadTest.counter ++ ;
System.out.println(ThreadTest.counter);
ThreadTest.class.notifyAll();
}
}
}
}
package test;
public class Runnable2 implements Runnable {
@Override
public void run() {
for (int i= 0 ; i < 1000000 ; i ++)
{
synchronized (ThreadTest.class) {
if (ThreadTest.counter < 0)
try {
ThreadTest.class.wait();
} catch (InterruptedException e) {
throw new RuntimeException(e.getMessage());
}
ThreadTest.counter -- ;
ThreadTest.class.notifyAll();
}
}
}
}
wait和notifyall的使用需要在synchronized段内且与synchronized锁定的对象为同一对象,因为wait调用需要释放一个锁,如果锁不存在就抛异常。