在Java中,可以使用synchronized
关键字和wait()
、notify()
方法来实现多线程交替打印奇偶数。下面是一个简单的示例:
public class AlternatePrinting {
private static final Object lock = new Object();
private static int count = 1;
public static void main(String[] args) {
Thread oddThread = new Thread(new OddNumberPrinter(), "OddThread");
Thread evenThread = new Thread(new EvenNumberPrinter(), "EvenThread");
oddThread.start();
evenThread.start();
}
static class OddNumberPrinter implements Runnable {
@Override
public void run() {
while (count <= 100) {
synchronized (lock) {
if (count % 2 == 1) {
System.out.println(Thread.currentThread().getName() + ": " + count++);
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
}
static class EvenNumberPrinter implements Runnable {
@Override
public void run() {
while (count <= 100) {
synchronized (lock) {
if (count % 2 == 0) {
System.out.println(Thread.currentThread().getName() + ": " + count++);
lock.notify();
} else {
try {
lock.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
}
}
在这个示例中,我们创建了两个线程:oddThread
和evenThread
。oddThread
负责打印奇数,evenThread
负责打印偶数。它们共享一个锁对象lock
和一个静态变量count
。
当count
为奇数时,oddThread
获取锁并打印数字,然后增加count
并调用lock.notify()
唤醒等待的线程。接着,oddThread
调用lock.wait()
释放锁并进入等待状态。
当count
为偶数时,evenThread
的行为与oddThread
类似。
这样,两个线程就可以交替打印奇偶数了。