在這個模型中我們需要有三個主要類,分別是商品類,生產者類以及消費者類。
其中運行機制和我們平時的生產者與消費者的關係機制大同小異。
在這個模型中,我們需要定義一個容器來實現消費者與生產者之間的解耦,爲了更貼近實際,採用FIFO原則的隊列作爲容器爲最佳選擇,並且此模型還遵循着以下兩條規則:
1.當生產者生產商品數量超過容器限制時,停止生產;
2.當消費者消費商品導致容器爲空時,停止消費。
以下通過兩種方式來實現這個模型。
第一種方式:wait()方法和notify()方法
注意:在這個方法中需要把容器作爲對象賦鎖。
首先定義一個商品類:
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 +
'}';
}
}
定義一個生產者類:
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() + "容器已滿,停止生產");
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() + "生產了一個" + goods);
}
}
}
}
}
定義一個消費者類:
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,開始生產");
this.queue.notifyAll();
} else {
Goods goods = this.queue.poll();
System.out.println(Thread.currentThread().getName() + "消費了一個" + goods);
}
}
}
}
}
最後定義一個測試用例:
public static void code1() {
//生產者
//消費者
//容器
Queue<Goods> queue = new LinkedList<>();
Runnable produce = new Producer(queue);
Runnable consumer = new Consumer(queue);
//生產者線程
for (int i = 0; i < 5; i++) {
new Thread(produce, "生產者-" + i).start();
}
//消費者線程
for (int i = 0; i < 2; i++) {
new Thread(consumer, "消費者-" + i).start();
}
}
方法二:使用阻塞隊列(這個方法好像還有一點問題,回頭再重新修改)
由於BlockingQueue接口自帶阻塞的功能,所以也不需要格外加鎖。
如果該隊列已滿,該線程被阻塞;如果該隊列已空,該線程也被阻塞。
首先定義一個商品類:
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 +
'}';
}
}
定義一個生產者類:
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() + "準備生產!");
try {
Thread.sleep(500);
queue.put(goods);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + "生產完成:" + goods);
}
}
}
定義一個消費者類:
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() + "準備消費!");
try {
Thread.sleep(500);
Goods1 goods = queue.take();
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + "消費完成:" + goods);
}
}
}
最後定義一個測試用例:
public static void main(String[] args) {
BlockingQueue<Goods1> queue = new ArrayBlockingQueue<>(3);
Runnable produce = new Producer1(queue);
Runnable consumer = new Consumer1(queue);
//生產者線程
for (int i = 0; i < 3; i++) {
new Thread(produce, "生產者-" + i).start();
}
//消費者線程
for (int i = 0; i < 2; i++) {
new Thread(consumer, "消費者-" + i).start();
}
}
以上就是實現生產者與消費者模型的兩種方式。