[英]send data from android to a udp port in web server2008
我想将数据(经度和纬度)发送到从我的android应用程序知道其ip和udp端口的Web服务器(Windows Server 2008)。如何执行此操作?这是示例代码,我正在尝试,但数据不是收到另一端
公共类UDPServer扩展Activity {
WebView view;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState) ;
setContentView(R.layout.main);
view=(WebView) findViewById(R.id.webView1);
try {
String serverHostname = new String ("ip and udp port");
BufferedReader inFromUser =
new BufferedReader(new InputStreamReader(System.in));
DatagramSocket clientSocket = new DatagramSocket();
InetAddress IPAddress = InetAddress.getByName(serverHostname);
System.out.println ("Attemping to connect to " + IPAddress +
") via UDP port 7777");
byte[] sendData = new byte[1024];
byte[] receiveData = new byte[1024];
System.out.print("Enter Message: ");
String sentence = inFromUser.readLine();
sendData = sentence.getBytes();
Log.i("send","send");
System.out.println ("Sending data to " + sendData.length +
" bytes to server.");
DatagramPacket sendPacket =
new DatagramPacket(sendData, sendData.length, IPAddress,7777);
clientSocket.send(sendPacket);
DatagramPacket receivePacket =
new DatagramPacket(receiveData, receiveData.length);
System.out.println ("Waiting for return packet");
clientSocket.setSoTimeout(10000);
try {
clientSocket.receive(receivePacket);
String modifiedSentence =
new String(receivePacket.getData());
InetAddress returnIPAddress = receivePacket.getAddress();
int port = receivePacket.getPort();
System.out.println ("From server at: " + returnIPAddress +
":" + port);
System.out.println("Message: " + modifiedSentence);
}
catch (SocketTimeoutException ste)
{
System.out.println ("Timeout Occurred: Packet assumed lost");
}
clientSocket.close();
}
catch (UnknownHostException ex) {
System.err.println(ex);
}
catch (IOException ex) {
System.err.println(ex);
}
}
在UDP中,与TCP不同,没有建立连接。 每个UDP数据包都自己传输。
我的猜测是您可以将UDP数据包发送到服务器,但是您没有收到返回数据包。 原因是在所有家用路由器和蜂窝网络上都使用了NAT 。 NAT阻止传送入站(互联网到设备)数据包。
要测试此假设,请在同一局域网上对设备和服务器进行尝试。
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