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Java UDP服务器不工作

udp java

en Lopes · 技术社区 · 6 年前

我创建了这个SpringBoot应用程序,探索通过用户数据报协议与Java进行网络通信。我正在Eclipse Java EE IDE中为Web开发人员运行该应用程序,版本:Oxygen。1a发布(4.7.1a)

主要类别如下:

@Override
    public void run(String... args) throws Exception {

        socket = new DatagramSocket(UDP_PORT); 

        byte[] receiveData = new byte[BUFFER_SIZE];
        byte[] sendData    = new byte[BUFFER_SIZE];

        LOG.info("UDP server init...");

        while (true) {

            DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);              
            socket.receive(receivePacket);  

            String sentence = new String( receivePacket.getData(), 0, receivePacket.getLength() );

            LOG.info("recived [" + sentence + "] from " + receivePacket.getAddress());

            InetAddress IPAddress = receivePacket.getAddress();
            int port = receivePacket.getPort();

            DatagramPacket sendPacket = new DatagramPacket(receiveData, receiveData.length, IPAddress, receivePacket.getPort());
            socket.send (sendPacket);

        }       
    }

这里是我创建的用于测试服务器的客户端UDP类

public class UDPClient {

private final static int TCP_PORT = 5202;

    private DatagramSocket socket;
    private InetAddress address;

    private byte[] buf;

    public UDPClient() throws SocketException, UnknownHostException {
        socket = new DatagramSocket();  
        address = InetAddress.getByName("localhost");
    }

    public String sendEcho(String msg) throws IOException {

        buf = msg.getBytes();
        DatagramPacket packet = new DatagramPacket(buf, buf.length, address, TCP_PORT);
        socket.send(packet);
        packet = new DatagramPacket(buf, buf.length);
        socket.receive(packet);
        String received = new String(packet.getData(), 0, packet.getLength());

        return received;
    }

    public void close() {
        socket.close();
    }

    public static void main(String[] args) throws IOException, InterruptedException {
            UDPClient udpClient = new UDPClient();

            for (;;) {
                TimeUnit.SECONDS.sleep(3);
                System.out.println
                    (udpClient.sendEcho("cullons"));
            }
    }

}

在我的计算机中工作正常,然后我将UDPServer部署到服务器上,我使用ipconfig获取ip

IPv4地址………:214.146.86.201

然后我将“localhost”替换为“214.146.86.201”,但我在服务器中没有收到任何消息。

我已经做了 nc -vzu 214.146.86.201 5202 从我的计算机

结果是:

 MacBook-Pro-de-lopes:$ nc -vzu 214.146.86.201 5202
found 0 associations
found 1 connections:
     1: flags=82<CONNECTED,PREFERRED>
    outif (null)
    src 192.166.26.140 port 56827
    dst 214.146.86.201 port 5202
    rank info not available

Connection to 214.146.86.201 port 5202 [udp/*] succeeded!

但服务器打印 无效的 在…上 LOG.info("socket InetAddres: " + socket.getInetAddress()); 和 LOG.info("socket RemoteSocketAddress: " + socket.getRemoteSocketAddress());

我也试过服务器 socket = new DatagramSocket(UDP_PORT, InetAddress.getByName("214.146.86.201")); 同样的结果

1 回复 | 直到 6 年前

zaerymoghaddam 6 年前

最可能的问题可能是客户端无法访问服务器上的5202端口。端口及其可访问性可能与TCP不同,但无论如何,中间总是有人丢弃您的数据包。

最简单的解决方法是尝试在服务器上运行客户端和服务器代码(214.146.86.201)。如果它可以连接,则意味着肯定存在通信问题,您可以使用所述的Netcat进行检查 here . 我自己没有试过。