BlockingQueue 實現生產者消費者問題

• FIFO 隊列 ：LinkedBlockingQueue、ArrayBlockingQueue（固定長度）
• 優先級隊列 ：PriorityBlockingQueue

提供了阻塞的 take() 和 put() 方法：如果隊列爲空 take() 將阻塞，直到隊列中有內容；如果隊列爲滿 put() 將阻塞，直到隊列有空閒位置。

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

public class ProducerConsumer {

    private static BlockingQueue<String> queue = new ArrayBlockingQueue<>(10);
    
    private static class Producer extends Thread{
        @Override
        public void run() {
            try {
                queue.put("product");
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("produce...");
        }
    }
    private static class Consumer extends Thread{
        @Override
        public void run() {
            try {
                String product = queue.take();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("consume...");
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i < 4; i++) {
            Producer producer = new Producer();
            producer.start();
        }
        for (int i = 0; i < 10; i++) {
            Consumer consumer = new Consumer();
            consumer.start();
        }
        for (int i = 0; i < 6; i++) {
            Producer producer = new Producer();
            producer.start();
        }
    }
}

produce...
produce...
produce...
produce...
produce...
consume...
consume...
consume...
consume...
consume...
produce...
produce...
consume...
consume...
produce...
consume...
produce...
consume...
produce...
consume...