用信号量解决生产者消费者问题

import java.util.concurrent.Semaphore;

class Q { //仓库
int n; //仓库中的产品

// Start with consumer semaphore unavailable.
static Semaphore semCon = new Semaphore(0);
static Semaphore semProd = new Semaphore(1);

void get() {
try {
semCon.acquire();
} catch(InterruptedException e) {
System.out.println("InterruptedException caught");
}

System.out.println("Got: " + n);
semProd.release();
}

void put(int n) {
try {
semProd.acquire();
} catch(InterruptedException e) {
System.out.println("InterruptedException caught");
}

this.n = n;
System.out.println("Put: " + n);
semCon.release();
}
}

class Producer implements Runnable { //生产者
Q q;

Producer(Q q) {