我试图通过使用来实现生产者和消费者问题的semaphores在java中。 问题是，当我开始两个线程（生产者和消费者）的消费者不启动和制片块本身缓冲区已满后。 我的意思是，它看起来像只有一个线程这在同步的方式工作。 因此，正如我所提到我使用3个信号量，其是空的，满，和互斥。 这是最简单的代码;
制作类;
import java.util.concurrent.Semaphore;
public class Producer implements Runnable {
private Semaphore empty;
private Semaphore full;
private Semaphore mutex;
public Producer(Semaphore empty, Semaphore full, Semaphore mutex) {
this.empty = empty;
this.full = full;
this.mutex = mutex;
}
@Override
public void run() {
while (true) {
try {
empty.acquire();
mutex.acquire();
Thread.sleep(500);
System.out.println("Producer producess an element");
mutex.release();
full.release();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
消费类;
import java.util.concurrent.Semaphore;
public class Consumer implements Runnable {
private Semaphore empty;
private Semaphore full;
private Semaphore mutex;
public Consumer(Semaphore empty, Semaphore full, Semaphore mutex) {
this.empty = empty;
this.full = full;
this.mutex = mutex;
}
@Override
public void run() {
while (true) {
try {
full.acquire();
mutex.acquire();
Thread.sleep(500);
System.out.println("Consumer consumes an element");
mutex.release();
empty.release();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
ProducerConsumerExample类
import java.util.concurrent.Semaphore;
public class ProducerConsumerProblem {
private Semaphore empty;
private Semaphore full;
private Semaphore mutex;
public ProducerConsumerProblem(int empty, int full) {
this.empty = new Semaphore(empty);
this.full = new Semaphore(full);
this.mutex = new Semaphore(1);
}
public void runProducerConsumerExample() {
Producer producer = new Producer(empty, full, mutex);
Consumer consumer = new Consumer(empty, full, mutex);
Thread p = new Thread(producer);
Thread c = new Thread(consumer);
p.run();
c.run();
}
}
最后测试类
import org.junit.Before;
import org.junit.Test;
public class ProducerConsumerProblemTest {
private ProducerConsumerProblem testClass;
private static final int EMPTY = 10;
private static final int FULL = 0;
@Before
public void setUp() {
testClass = new ProducerConsumerProblem(EMPTY, FULL);
}
@Test
public void testName() {
testClass.runProducerConsumerExample();
}
}
输出：
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
Producer producess an element
经过10项生产没有任何反应和线程被阻塞。
