生产者是指:生产数据的线程
消费者是指:使用数据的线程
生产者和消费者是不同的线程,他们处理数据的速度是不一样的,一般在二者之间还要加个“桥梁参与者”,用于缓冲二者之间处理数据的速度差。
下面用代码来说明:
//生产者
public class MakerThread extends Thread { private final Random random; private final Table table; private static int id = 0; public MakerThread(String name, Table table, long seed) { super(name); this.table = table;//table就是桥梁参与者 this.random = new Random(seed); } public void run() { try { while (true) { Thread.sleep(random.nextInt(1000));//生产数据要耗费时间 //生产数据 String cake = "[ Cake No." + nextId() + " by " + getName() + " ]"; table.put(cake);//将数据存入桥梁参与者 } } catch (InterruptedException e) { } } private static synchronized int nextId() { return id++; } }
再来看看消费者:
//消费者线程
public classEaterThread extends Thread { private final Random random; private final Table table; public EaterThread(String name, Table table,long seed) { super(name); this.table = table; this.random = new Random(seed); } public void run() { try { while (true) { String cake = table.take();//从桥梁参与者中取数据 Thread.sleep(random.nextInt(1000));//消费者消费数据要花时间 } } catch (InterruptedException e) { } }}
看来在这个模式里table是个很重要的角色啊,让我们来看看他吧(这里只给出个简单的):
public class Table { private final String[] buffer; private int tail; //下一个放put(数据)的地方 private int head; //下一个取take(数据)的地方 private int count; // buffer内的数据数量 public Table(int count) { this.buffer = new String[count];//总量是确定的 this.head = 0; this.tail = 0; this.count = 0; } // 放置数据 public synchronized void put(String cake) throws InterruptedException { System.out.println(Thread.currentThread().getName() + " puts " + cake); while (count >= buffer.length) {//数据放满了就只能等待 wait(); } buffer[tail] = cake; tail = (tail + 1) % buffer.length; count++; notifyAll();//有数据了,唤醒线程去取数据 } // 取得数据 public synchronized String take() throws InterruptedException { while (count <= 0) {//没有数据就只能等待 wait(); } String cake = buffer[head]; head = (head + 1) % buffer.length; count--; notifyAll();//有位置可以放数据了,唤醒线程,不等了 System.out.println(Thread.currentThread().getName() + " takes " + cake); return cake; } }
好了我们来实验吧:
public class Main { public static void main(String[] args) { Table table = new Table(3); // 建立可以放置数据的桥梁参与者,3是他所能放置的最大数量的数据。 new MakerThread("MakerThread-1", table, 31415).start();//生产数据 new MakerThread("MakerThread-2", table, 92653).start(); new MakerThread("MakerThread-3", table, 58979).start(); new EaterThread("EaterThread-1", table, 32384).start();//消费数据 new EaterThread("EaterThread-2", table, 62643).start(); new EaterThread("EaterThread-3", table, 38327).start(); } } 需要各种it视频关注获取