Java 經典問題 生產者–消費者問題
現在有這樣一個問題,生產者不停的生產饅頭,消費者則不停的消費饅頭,同時我們把生產的饅頭存放到一個(籃子)即棧中。
有上面的描述,我可以抽出一下幾個類。
ManTou 饅頭類
StackBasket 籃子類(用於裝饅頭的類)
Producer 用於生產饅頭的類
Consumer 用於消費饅頭的類
ProducerAndConsumer 這個類爲測試類
/**
* @author yikai
* 饅頭類,就是一個實體類,就爲每一個饅頭設置一個id
*/
public class ManTou {
int id;
public ManTou(int id) {
this.id = id;
}
}
/**
* @author yikai
* 籃子類,設置爲一個棧結構,因此裏面設置一個push(壓棧)方法和一個pop(出棧)方法
* 因爲涉及到藍子的大小,以及多線程修改饅頭數量的問題,所以要加上synchronized
*/
public class StackBasket {
int index = 0;
ManTou manTous[] = new ManTou[5];
public synchronized void push(ManTou manTou) {
while (index == 5){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
manTous[index] = manTou;
index++;
this.notify();
}
public synchronized ManTou pop() {
while (index == 0){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
index--;
ManTou manTou = manTous[index];
this.notify();
return manTou;
}
}
/**
* @author yikai
* 生產者與消費者類似,將生產的饅頭放入到籃子,所以需要一個籃子對象,然後調用籃子的
* push方法,具體如下
*/
public class Producer implements Runnable {
private StackBasket stackBasket;
public Producer(StackBasket stackBasket) {
this.stackBasket = stackBasket;
}
@Override
public void run() {
for (int i = 0; i < 20; i++) {
ManTou manTou = new ManTou(i);
stackBasket.push(manTou);
System.out.println("producer: "+manTou.id);
try {
Thread.sleep(200);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
/**
* @author yikai
* 消費者就是從籃子裏面不停的拿饅頭,所以需要一個籃子對象,然後從籃子對象中取饅頭
* 具體如下代碼
*/
public class Consumer implements Runnable {
private StackBasket stackBasket;
public Consumer(StackBasket stackBasket){
this.stackBasket = stackBasket;
}
@Override
public void run() {
for (int i = 0; i < 20; i++) {
ManTou manTou = stackBasket.pop();
System.out.println("consumer"+" "+manTou.id);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
/**
* @author yikai
*/
public class ProducerAndConsumer {
public static void main(String[] arg) {
StackBasket stackBasket = new StackBasket();
Thread p = new Thread(new Producer(stackBasket));
Thread c = new Thread(new Consumer(stackBasket));
p.start();
c.start();
}
}