在Java中使用UDP跨网络发送对象 [英] Sending Objects Across Network using UDP in Java

问题描述

我还没有找到我所遇到的问题的确切答案，所以无论如何我都会提出这个问题，而事实上，如果我确实转发了已经提出的问题，我深表歉意.

I haven't found an exact answer to the problem that I'm having, so I'm going to ask this anyway, and if I did, in fact, repost a question that's already been asked, I apologize.

我正在为我的Java类做另一个实验作业，在本周的实验中，我必须制作一个UDP服务器以通过网络发送一个Message对象，然后我必须制作一个UDP客户端以读取该内容.信息.消息本身只是一个具有String消息和String用户名的对象；相当武断.消息是可序列化的.

I'm doing another lab assignment for my Java class, and for this week's lab, I have to make a UDP server to send out a Message object across the network, then I have to make a UDP client to read in that Message. The Message itself is just an Object that has a String message and a String username; fairly arbitrary. Message is Serializable.

现在，我遇到的问题是如何在DatagramPacket中通过网络实际发送该消息对象?实际的构造函数让我放入一个字节数组，该数组的大小，InetAddress和端口号.我的最后一个问题是:如何找出数组的大小，以及如何将我的消息转换为要发送的字节?

Now, what I'm having an issue with is how to actually go about sending that Message Object across the network within a DatagramPacket? The actual constructor has me put in a byte array, the size of the array, the InetAddress, and the port number. My final question is: how to I find out the size of the array, and how to I turn my Message into bytes to be sent out?

推荐答案

您需要将消息类序列化为字节数组.这将是您发送的字节数组(此时将很容易获得大小).

You need to serialize your message class into a byte array. This will be the byte array you send (and it will be easy to get the size at that point).

在客户端上，您需要将字节数组反序列化为Message对象.

On the client, you will want to deserialize the byte array back into a Message object.

Java提供了一组用于处理序列化/反序列化的类，要序列化的对象必须实现"Serializable"接口.

Java provides a set of classes to handle serialization/deserialization, and the object you want to serialize must implement the "Serializable" interface.

类似的事情会起作用:

// Serialize to a byte array
ByteArrayOutputStream bStream = new ByteArrayOutputStream();
ObjectOutput oo = new ObjectOutputStream(bStream); 
oo.writeObject(messageClass);
oo.close();

byte[] serializedMessage = bStream.toByteArray();

在接收端:

ObjectInputStream iStream = new ObjectInputStream(new ByteArrayInputStream(recBytes));
Message messageClass = (Message) iStream.readObject();
iStream.close();

请注意，您应该创建一个在客户端和服务器之间共享的通用接口，这将使有效负载的序列化/反序列化变得容易.

Note, you should create a common interface that is shared between the client and the server, this will allow for easy serialization/deserialization of the payload.

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