Hello I have a code written in Java and I need to create an TCP Connection with GPS device in android studio, where you can type in IP/PORT addresses, if someone can help me thanks in advance.
public class TCPConnection implements Runnable {
/**
* <h1>TCP Connection construct</h1>
* <p>The tcp connection requires two parameters socket and view model. </p>
* @param socket to establish connection.
* */
TCPConnection(Socket socket) {
super();
this.socket = socket;
converter = new Converter();
crc16 = new Crc16();
}
/**
* <h1>Run function to start listener</h1>
* <p>Simply runs the runnable thread to listen everything from client</p>
* */
public void run() {
try {
inputStream = new DataInputStream(socket.getInputStream());
outputStream = new DataOutputStream(socket.getOutputStream());
Listen();
} catch (IOException e) {
e.printStackTrace();
}
}
Probably I need to create an button to start Listen incoming connections, also use Log class .....
/**
* <h1>Listen</h1>
* <p>Function for listening connected client</p>
* @throws IOException throws exception if input stream is interrupted
* */
private void Listen() throws IOException {
while (flag) {
System.out.println("listening...");
while (!socket.isClosed() && inputStream.available() == 0) {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
break;
}
}
Communicate();
}
inputStream.close();
outputStream.close();
socket.close();
}
/**
* <h1>Get Number Of Records</h1>
* <p>Reads the number of records to send back to the sender</p>
* @param data the parameter is a received hex data
* @return String format number of records
* */
private String GetNumberOfRecords(String data) {
return data.substring(18, 20);
}
Everything is written in a comments line, why stackoverflow says add more details :D...
/**
* <h1>Communicate</h1>
* <p>A reader and sender with client, first it reads imei, then sends back 01.
* It receives data, as soon it receives it sends back number of records.
* The while loop initializes and runs until it get interrupted or client disconnects.</p>
* */
private void Communicate() {
imei = Objects.requireNonNull(ReadInput()).substring(4);
imei = converter.ReadImei(imei);
String path = System.getProperty("user.home") + "/Desktop";
logger = new Logger(path+"/Logs/TCPLogs/"+imei);
logger.PrintToLOG(GetTime()+" IMEI: " +imei);
if(imei.length() < 15){
SendOutput("00");
}
else{
SendOutput("01");
logger.PrintToLOG("\tResponse: [0" + 1 + "]");
String input = ReadInput();
Log(Objects.requireNonNull(input));
while(flag){
String recordsCount = GetNumberOfRecords(input);
SendOutput("000000" + recordsCount);
logger.PrintToLOG("\tCrc: " + Integer.toHexString(CRC(input)));
logger.PrintToLOG("\tResponse: [000000" + recordsCount + "]\n");
input = ReadInput();
Log(Objects.requireNonNull(input));
}
}
/**
* <h1>Send Output</h1>
* <p>Sends output to the client</p>
* @param message the parameter is a received hex data
* */
private void SendOutput(String message) {
try {
outputStream.write(converter.StringToByteArray(message));
outputStream.flush();
} catch (IOException e) {
System.out.println("Output stream was interrupted");
}
}
/**
* <h1>CRC</h1>
* <p>Calculates CRC of received data</p>
* @param str the parameter is a received hex data
* @return int of crc16
* */
private int CRC(String str) {
str = str.substring(16, str.length() - 8);
byte[] bytes = converter.StringToByteArray(str);
return crc16.getCRC(bytes);
}
/**
* <h1>Read Input</h1>
* <p>Reads the input from client. Currently maximum message byte is set up to 8192,
* if message is bigger then message will not be properly readable and displayed.</p>
* @return String of received data
* */
private String ReadInput() {
byte[] messageByte = new byte[8192];
int dataSize;
try {
dataSize = inputStream.read(messageByte);
String finalInput = converter.BytesArrayToHex(messageByte, dataSize);
SendToConsole(finalInput);
return finalInput;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* <h1>Send To Console</h1>
* <p>Simply prints out the results to the text area for user</p>
* @param input the parameter is String format to print in text area
* */
private void SendToConsole(String input) {
if(imei!=null)
{
String message = viewModel.getClientMessage() + "\r\nFrom imei - "+imei+" : " + input + "\n" + repeatChar();
Platform.runLater(() -> viewModel.setClientMessage(message));
}
else {
String message = viewModel.getClientMessage() + "\r\nReceived imei - : " + input + "\n" + repeatChar();
Platform.runLater(() -> viewModel.setClientMessage(message));
}
}
/**
* <h1>Log</h1>
* <p>Given String is being written to log file.</p>
* @param data the parameter is a received data
* */
private void Log(String data) {
logger.PrintToLOG("\tcodec : " + data.substring(16, 18));
logger.PrintToLOG("\tNumber of Records : " + GetNumberOfRecords(data));
logger.PrintToLOG("\tAVL data : " + data + "\n");
}
/**
* <h1>Set Running</h1>
* <p>Sets flag to run or stop while loop in order to interrupt the thread.</p>
* */
void setRunning() {
this.flag = false;
}
/**
* <h1>Repeat Char</h1>
* <p>Repeats the '=' character multiple times.</p>
* @return String is being returned.
* */
private String repeatChar() {
char[] data = new char[50];
Arrays.fill(data, '=');
return new String(data);
}
/**
* <h1>Get Time</h1>
* <p>Gets time when method is being called</p>
* @return Time in String format
* */
private String GetTime()
{
LocalDateTime localDateTime = LocalDateTime.now();
LocalTime localTime = localDateTime.toLocalTime();
return localTime.toString();
}
}
public class TCPServer implements Runnable {
private int port;
private Socket socket;
private ServerSocket ss;
private boolean running = true;
private ArrayList<TCPConnection> tcpConnections;
/**
* <h1>TCP server construct</h1>
* <p>The tcp server takes port parameter </p>
* @param port is required for server to listen all incoming connections
* */
public TCPServer(int port) {
this.port = port;
}
/**
* <h1>Run</h1>
* <p>Runs the runnable thread to listen connections, it accepts a connection, if accept was successful,
* the connection is added to tcpConnections list and runs the TCPConnection for further listening.
* The server is running in while loop and stops when Running is set to false,
* then break is called and shutdowns every connected client.</p>
* */
public void run() {
tcpConnections = new ArrayList<>();
try {
ss = new ServerSocket(port);
System.out.println("Listening on port : " + ss.getLocalPort());
ExecutorService executorService;
while (true) {
executorService = Executors.newSingleThreadExecutor();
socket = ss.accept();
TCPConnection connection = new TCPConnection(socket);
executorService.submit(connection);
tcpConnections.add(connection);
if (!running) {
StopConnections();
break;
}
}
executorService.shutdownNow();
Thread.sleep(100);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
} catch (IOException e) {
System.out.println("socket is closed");
}
}
/**
* <h1>Set Flag</h1>
* <p>Function is being called when we want to interrupt server thread and stop it.</p>
* @param flag the parameter sets whenever to true(run server) or false(stop server)
* */
public void setFlag(boolean flag) {
running = flag;
if (!running) {
try {
ss.close();
if (socket != null)
socket.close();
} catch (IOException e) {
System.out.println("Socket is " + socket.isClosed());
}
}
}
/**
* <h1>Stop Connections</h1>
* <p>Function is being called when we are stopping server,
* this function iterates through every connection and stops it.</p>
* */
private void StopConnections() {
if (!tcpConnections.isEmpty()) {
for (TCPConnection connections : tcpConnections) {
connections.setRunning();
}
tcpConnections.clear();
}
}
}
