在这个模型中我们需要有三个主要类,分别是商品类,生产者类以及消费者类。
其中运行机制和我们平时的生产者与消费者的关系机制大同小异。
在这个模型中,我们需要定义一个容器来实现消费者与生产者之间的解耦,为了更贴近实际,采用FIFO原则的队列作为容器为最佳选择,并且此模型还遵循着以下两条规则:
1.当生产者生产商品数量超过容器限制时,停止生产;
2.当消费者消费商品导致容器为空时,停止消费。
以下通过两种方式来实现这个模型。
第一种方式:wait()方法和notify()方法
注意:在这个方法中需要把容器作为对象赋锁。
首先定义一个商品类:
class Goods {
private String name;
private String id;
private Double price;
public Goods(String name, String id, Double price) {
this.name = name;
this.id = id;
this.price = price;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
@Override
public String toString() {
return "Goods{" +
"name='" + name + '\'' +
", id='" + id + '\'' +
", price=" + price +
'}';
}
}
定义一个生产者类:
class Producer implements Runnable {
private final Queue<Goods> queue;
public Producer(Queue<Goods> queue) {
this.queue = queue;
}
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (this.queue) {
if (queue.size() >= 3) {
System.out.println(Thread.currentThread().getName() + "容器已满,停止生产");
try {
this.queue.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
} else {
String id = UUID.randomUUID().toString();
String name = "包子";
Double price = new Random().nextDouble();
Goods goods = new Goods(id, name, price);
queue.add(goods);
System.out.println(Thread.currentThread().getName() + "生产了一个" + goods);
}
}
}
}
}
定义一个消费者类:
class Consumer implements Runnable {
private Queue<Goods> queue;
public Consumer(Queue<Goods> queue) {
this.queue = queue;
}
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
synchronized (this.queue) {
if (this.queue.isEmpty()) {
System.out.println(Thread.currentThread().getName() + "容器已空,开始生产");
this.queue.notifyAll();
} else {
Goods goods = this.queue.poll();
System.out.println(Thread.currentThread().getName() + "消费了一个" + goods);
}
}
}
}
}
最后定义一个测试用例:
public static void code1() {
//生产者
//消费者
//容器
Queue<Goods> queue = new LinkedList<>();
Runnable produce = new Producer(queue);
Runnable consumer = new Consumer(queue);
//生产者线程
for (int i = 0; i < 5; i++) {
new Thread(produce, "生产者-" + i).start();
}
//消费者线程
for (int i = 0; i < 2; i++) {
new Thread(consumer, "消费者-" + i).start();
}
}
方法二:使用阻塞队列(这个方法好像还有一点问题,回头再重新修改)
由于BlockingQueue接口自带阻塞的功能,所以也不需要格外加锁。
如果该队列已满,该线程被阻塞;如果该队列已空,该线程也被阻塞。
首先定义一个商品类:
class Goods1 {
private String name;
private String id;
private Double price;
public Goods1(String name, String id, Double price) {
this.name = name;
this.id = id;
this.price = price;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
@Override
public String toString() {
return "Goods{" +
"name='" + name + '\'' +
", id='" + id + '\'' +
", price=" + price +
'}';
}
}
定义一个生产者类:
class Producer1 implements Runnable {
private BlockingQueue<Goods1> queue;
public Producer1(BlockingQueue<Goods1> queue) {
this.queue = queue;
}
@Override
public void run() {
String id = UUID.randomUUID().toString();
String name = "包子";
Double price = new Random().nextDouble();
Goods1 goods = new Goods1(id, name, price);
while (true) {
System.out.println(Thread.currentThread().getName() + "准备生产!");
try {
Thread.sleep(500);
queue.put(goods);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + "生产完成:" + goods);
}
}
}
定义一个消费者类:
class Consumer1 implements Runnable {
private BlockingQueue<Goods1> queue;
public Consumer1(BlockingQueue<Goods1> queue) {
this.queue = queue;
}
@Override
public void run() {
while (true) {
System.out.println(Thread.currentThread().getName() + "准备消费!");
try {
Thread.sleep(500);
Goods1 goods = queue.take();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + "消费完成:" + goods);
}
}
}
最后定义一个测试用例:
public static void main(String[] args) {
BlockingQueue<Goods1> queue = new ArrayBlockingQueue<>(3);
Runnable produce = new Producer1(queue);
Runnable consumer = new Consumer1(queue);
//生产者线程
for (int i = 0; i < 3; i++) {
new Thread(produce, "生产者-" + i).start();
}
//消费者线程
for (int i = 0; i < 2; i++) {
new Thread(consumer, "消费者-" + i).start();
}
}
以上就是实现生产者与消费者模型的两种方式。