BlockingQueue的四组api测试

BlockingQueue（阻塞队列）

先看继承结构：

从图中看出BlockingQueue属于集合；

主要使用场景：多线程并发处理，线程池

使用：4组api

方法	抛异常	不抛出异常，有返回值	阻塞	超时
插入方法	add(o)	offer(o)	put(o)	offer(o, timeout, timeunit)
移除方法	remove()	poll()	take()	poll(timeout, timeunit)
检查方法	element()	peek()

测试1.：add(o) remove(o) element()

1. add(o) 当增加超过队列数量报出异常

public class BlockingQueueDemo {
    public static void main(String[] args) {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        blockingQueue.add(1);
        blockingQueue.add(1);
        blockingQueue.add(1);
        blockingQueue.add(1);
    }
}

           

1.2 remove() 当队列为空时去取报出异常

public class BlockingQueueDemo {
    public static void main(String[] args) {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        blockingQueue.remove();

    }
}
           

1.3 element() 当队列为空时去检查报出异常

public class BlockingQueueDemo {
    public static void main(String[] args) {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        Object element = blockingQueue.element();
        System.out.println(element);
    }
}
           

测试2：offer(o) poll() peek()

2.1 offer() 当队列增加超出队列长度时返回false,poll()取完时返回null，，peek()首元素为空时返回null

public class BlockingQueueDemo {
    public static void main(String[] args) {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        System.out.println(blockingQueue.offer(1));
        System.out.println(blockingQueue.offer(1));
        System.out.println(blockingQueue.offer(1));
        System.out.println(blockingQueue.offer(1));
        //取值
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        System.out.println(blockingQueue.poll());
        //检擦首元素
        System.out.println(blockingQueue.peek());
    }
}

           

测试3：put(o) 当队列增加超出队列长度时会一只阻塞, take()

3.1 put(o)

public class BlockingQueueDemo {
    public static void main(String[] args) throws InterruptedException {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        blockingQueue.put(1);
        blockingQueue.put(1);
        blockingQueue.put(1);
        blockingQueue.put(1);

    }
}
           

3.2 take()

public class BlockingQueueDemo {
    public static void main(String[] args) throws InterruptedException {
        //队列长度
        ArrayBlockingQueue blockingQueue = new ArrayBlockingQueue<>(3);
        blockingQueue.put(1);
        blockingQueue.put(1);
        blockingQueue.put(1);
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take());
        System.out.println(blockingQueue.take());
    }
}

           

offer(o, timeout, timeunit)，poll(timeout, timeunit)

类似第三组 唯一区别就是可以设置等待时间，如果超时则退出