java中BlockingQueue / ArrayBlockingQueue的序列化

Question

I need to "serialize" a large BlockingQueue(sizeof 10_000) that contains domanis names (Strings(Objects) ) for my crawler - for example if I will stop stop it or it will happen accidentally - this will help not to crawl that was already done. What is the best way to do it? In NET I have used the binary serialization for such tasks (like protobuf for example) (it is faster and serialized information visualization not so critical for understanding -so not necessary XML view). But how to do this in java? May be you an reference on a sample?

Answer 1

BlockingQueue is just an interface, not a concrete type. You serialize/deserialize instances which have concrete types. It depends whether the dynamic type of the instace you have implements Serializable .

ArrayBlockingQueue implements Serializable which means you can simply serialize it and deserialize it with an ObjectInputStream / ObjectOutputStream :

Saving an ArrayBlockingQueue :

ArrayBlockingQueue queue = new ArrayBlockingQueue(10);

try (ObjectOutputStream out = new ObjectOutputStream(
        new FileOutputStream("queue.data"))) {
    out.writeObject(queue);
}

Reading a persisted ArrayBlockingQueue :

ArrayBlockingQueue queue = null;

try (ObjectInputStream in = new ObjectInputStream (
        new FileInputStream("queue.data"))) {
    queue = in.readObject()
}

Answer 2

BlockingQueue interface in java has implementation by some classes such as ArrayBlockingQueue, DelayQueue, LinkedBlockingQueue, and others.

Below are important methods of blocking queues.

E take() - consumes element from queue, waits if queue is empty until producer produces something into the queue.

put(E) - producer puts element into queue, waits if queue is full until consumer consumes item(s) from the queue.

more info @ oracle docs .