android udp demo

最新推荐文章于 2023-02-16 14:52:58 发布

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本文介绍了一个使用Java实现的UDP消息发送与接收的基本示例。该示例包括创建DatagramSocket对象、构造并发送UDP数据包以及接收响应的过程。通过这个简单的例子，读者可以了解如何利用Java进行基本的UDP通信。

public void sendUDPmsg(){
DatagramSocket sendSocket = null;
try {

        sendSocket = new DatagramSocket();
    } catch (SocketException e) {
        e.printStackTrace();
    }


    String ServerIp = "114.55.89.143";
    InetAddress ip = null;
    int port = 7777;
    try {
        ip = InetAddress.getByName(ServerIp);
    } catch (UnknownHostException e) {
        e.printStackTrace();
    }
    byte[] bys = new byte[]{};
    DatagramPacket sendPacket = new DatagramPacket(bys, bys.length, ip,
            port);
    try {
        sendSocket.send(sendPacket);
    } catch (IOException e) {
        e.printStackTrace();
    }
    byte[] getBuf = new byte[256];
    DatagramPacket getPacket = new DatagramPacket(getBuf, getBuf.length);
    try {
        sendSocket.setSoTimeout(4000);
    } catch (SocketException e) {
        e.printStackTrace();
    }
    try {
        sendSocket.receive(getPacket);
    } catch (IOException e) {
        e.printStackTrace();
    }
    StringBuffer bd = new StringBuffer();
    for (int iu = 0; iu < getPacket.getLength(); iu++) {
        String hex = Integer.toHexString(getBuf[iu] & 0xFF)
                .toUpperCase();
        if (hex.length() == 1) {
            hex = '0' + hex;
        }
        bd.append(hex);
    }
    String res = bd.toString();
    System.out.println(res + "发送回复");

}