Java中的网络发现使用多播 [英] Network discovery in Java using multicasting

问题描述

我正在尝试制作客户端/服务器Java App。客户端和服务器都将在同一个Wi-Fi网络上运行。服务器将在客户端知道的特定端口上运行。

I'm trying to make a client/server Java App. Both client and server will be running on the same wi-fi network. Server will be running on a specific port that client is aware of.

我打算通过网络从客户端发送多播消息，以发现该服务器。但是，我不太清楚如何找出网络中的哪些IP收到了我的消息。

I am planning to send a multicast message from client through the network for that specific port to discover the server. However, I'm not too sure how I can find out which IP in my network received my message.

我是否需要在客户端上创建一个套接字并在发送多播消息后侦听传入的数据包，以防服务器回复？

Do I need to create a socket on the client and listen to incoming packets once I send my multicast message in case server replies back?

提前致谢。

推荐答案

（1）服务器侦听预先安排好的端口

(1)server listens on a pre-arranged port

DatagramSocket s = new DatagramSocket(8888);
s.receive  //(1)
s.send     //(2)

（3）客户端在广播IP上向端口发送消息，255.255.255.255

(3)client sends a message to the port, on the broadcast IP, 255.255.255.255

DatagramSocket c = new DatagramSocket();
c.send(255.255.255.255:8888,msg)     //(3)
c.receive  //(4)

客户端也绑定到端口。我们没有指定它，所以我们随机选择它。

the client binds to a port too. we didn't specify it, so it's random chosen for us.

（3）将消息广播到所有本地机器，服务器在（1）接收消息，客户端IP：端口。

(3) will broadcast the message to all local machines, server at (1) receives message, with the client IP:port.

（2）服务器向客户端IP发送响应消息：端口

(2) server sends response message to client IP:port

（4 ）客户端从服务器获取响应消息。

(4) client gets the reponse message from server.

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