（转自：https://blog.csdn.net/antony9118/article/details/51500278 侵删）
这篇博客算是上一篇JAVA多线程（三）生产者消费者模式及实现方法的补充。用三种方法（lock、synchronized、阻塞队列）实现生产者消费者模式。具体内容是：生产者产生随机数（为了方便阅读结果，我把随机数限定在10以内的整数），消费者读取并打印。
1 阻塞队列实现生产者消费者模式
阻塞队列是最简单的实现方法
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.Random;
public class BlockingQueuePattern {
public static void main(String args[]){
//阻塞队列
BlockingQueue sharedQueue = new LinkedBlockingQueue();
//创建生产者线程和消费者线程
Thread prodThread = new Thread(new Producer(sharedQueue));
Thread consThread = new Thread(new Consumer(sharedQueue));
//启动生产者线程和消费者线程
prodThread.start();
consThread.start();
}
}
//生产者类
class Producer implements Runnable {
private final BlockingQueue sharedQueue;
public Producer(BlockingQueue sharedQueue) {
this.sharedQueue = sharedQueue;
}
@Override
public void run() {
for(int i=0; i<10; i++){
try {
//产生10以内的随机整数放入阻塞队列
Random random = new Random();
int ProdRandom=random.nextInt(10);
System.out.println("Produced: " + ProdRandom);
sharedQueue.put(ProdRandom);
} catch (InterruptedException ex) {
Logger.getLogger(Producer.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
//消费者类
class Consumer implements Runnable{
private final BlockingQueue sharedQueue;
public Consumer (BlockingQueue sharedQueue) {
this.sharedQueue = sharedQueue;
}
@Override
public void run() {
while(true){
try {
System.out.println("Consumed: "+ sharedQueue.take());
} catch (InterruptedException ex) {
Logger.getLogger(Consumer.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
Output：
Produced: 4
Produced: 7
Produced: 8
Consumed: 4
Consumed: 7
Produced: 6
Consumed: 8
Consumed: 6
Produced: 1
Produced: 7
Consumed: 1
Consumed: 7
Produced: 3
Produced: 5
Consumed: 3
Consumed: 5
Produced: 9
Produced: 7
Consumed: 9
Consumed: 72 lock实现生产者消费者模式
既然不用JAVA提供给我们的现成的阻塞队列，我们不如自己创建一个队列，代码如下:
import java.util.LinkedList;
import java.util.Random;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class OptimisticLockPattern {
public static void main(String[] args){
SelfQueue selfqueue = new SelfQueue();
//创建生产者线程和消费者线程
Thread prodThread = new Thread(new Producer(selfqueue));
Thread consThread = new Thread(new Consumer(selfqueue));
//启动生产者线程和消费者线程
prodThread.start();
consThread.start();
}
}
class SelfQueue{
int max = 5;
LinkedList<Integer> ProdLine = new LinkedList<Integer>();
Lock lock = new ReentrantLock();
Condition full = lock.newCondition();
Condition empty = lock.newCondition();
public void produce(int ProdRandom){
try {
lock.lock();
while(max == ProdLine.size()){
System.out.println("存储量达到上限，请等待");
full.await();
}
ProdLine.add(ProdRandom);
empty.signal();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
lock.unlock();
}
}
public int consume(){
int m = 0;
try {
lock.lock();
while(ProdLine.size() == 0){
System.out.println("队列是空的，请稍候");
empty.await();
}
m = ProdLine.removeFirst();
full.signal();
} catch (InterruptedException e) {
e.printStackTrace();
}finally{
lock.unlock();
return m;
}
}
}
//生产者
class Producer implements Runnable{
private final SelfQueue selfqueue;
public Producer(SelfQueue selfqueue) {
this.selfqueue = selfqueue;
}
public void run() {
for (int i = 0; i < 10; i++) {
Random random = new Random();
int ProdRandom=random.nextInt(10);
System.out.println("Produced: " + ProdRandom);
selfqueue.produce(ProdRandom);
}
}
}
//消费者
class Consumer implements Runnable{
private final SelfQueue selfqueue;
public Consumer(SelfQueue selfqueue) {
this.selfqueue = selfqueue;
}
public void run() {
while(true) {
System.out.println("Consumed: "+ selfqueue.consume());
}
}
}
Output:
Produced: 1
Produced: 9
Consumed: 1
Consumed: 9
队列是空的，请稍候
Produced: 9
Produced: 1
Consumed: 9
Produced: 8
Consumed: 1
Consumed: 8
队列是空的，请稍候
Produced: 6
Produced: 8
Consumed: 6
Produced: 4
Consumed: 8
Produced: 4
Consumed: 4
Produced: 0
Consumed: 4
Consumed: 0
队列是空的，请稍候3 synchronized实现生产者消费者模式
synchronized不需要自己手动解锁，这里用到了前面提过的wait()¬ify()方法。
import java.util.Random;
public class PessimisticLockPattern {
public static void main(String[] args){
SelfQueue selfqueue = new SelfQueue();
//创建生产者线程和消费者线程
Thread prodThread = new Thread(new Producer(selfqueue));
Thread consThread = new Thread(new Consumer(selfqueue));
//启动生产者线程和消费者线程
prodThread.start();
consThread.start();
}
}
class SelfQueue{
int index = 0;
int[] ProdLine = new int[6];
public synchronized void produce(int ProdRandom){
while(index == ProdLine.length){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
this.notify();
ProdLine[index] = ProdRandom;
index++;
}
public synchronized int consume(){
while(index == 0){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
this.notify();
index--;
return ProdLine[index];
}
}
//生产者
class Producer implements Runnable{
private final SelfQueue selfqueue;
public Producer(SelfQueue selfqueue) {
this.selfqueue = selfqueue;
}
public void run() {
for (int i = 0; i < 10; i++) {
Random random = new Random();
int ProdRandom = random.nextInt(10);
System.out.println("Produced: " + ProdRandom);
selfqueue.produce(ProdRandom);
}
}
}
//消费者
class Consumer implements Runnable{
private final SelfQueue selfqueue;
public Consumer(SelfQueue selfqueue) {
this.selfqueue = selfqueue;
}
public void run() {
while(true) {
System.out.println("Consumed: "+ selfqueue.consume());
}
}
}
Output:
Produced: 3
Produced: 3
Consumed: 3
Produced: 8
Produced: 3
Consumed: 3
Produced: 2
Produced: 6
Consumed: 3
Produced: 7
Produced: 8
Produced: 1
Produced: 9
Consumed: 6
Consumed: 9
Consumed: 1
Consumed: 8
Consumed: 7
Consumed: 2
Consumed: 8