Develop Reference

Java: serialport exception- port is busy

I have a bill validator attached to PC through com port. I try to send data to bill validator and receive output (bill validator communicates through ccnet protocol )
here is my code -
public static void main(String[] args) throws SerialPortException {
String s[]=SerialPortList.getPortNames();
for (String x :s){
System.out.print(x);
SerialPort serialPort=new SerialPort(x);
}
try {
SerialPort serialPort=new SerialPort("COM4");
serialPort.openPort();
serialPort.setParams(9600, 8, 1, SerialPort.PARITY_NONE);
serialPort.writeString("RESET");
serialPort.setEventsMask(SerialPort.MASK_RXCHAR);
serialPort.addEventListener(new list());
System.out.println(serialPort.readBytes(5));
} catch (SerialPortException sex){
System.out.print(sex);
}
serial port event listener:
private static class list implements SerialPortEventListener{
#Override
public void serialEvent(SerialPortEvent spe) {
if (spe.isRXCHAR()&&spe.getEventValue()>0){
try {
String data =s erialPort.readString(spe.getEventValue());
} catch (SerialPortException ex) {
Logger.getLogger(Terminal.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
So I get serial port exception port is busy , how can i fix that ?

Mostly this will occur in 2 situations:
1- You have assigned a wrong port which maybe another device, you can check it through your device manager.
2- You have opened it previously with another software or maybe your previous run of code is still using it and you haven't terminate it.
I see in your code you have first listed all your com ports but you don't benefit from it, it seems redundant.
I recommend you delete all lines in your try part of your code and just leave the openport line and do it for other lines to see which line gives the exception.

JSSC - Adding SerialPortEventListener to JFrame

I need some help on how EventListeners work in java. I'll be honest, the only Listener I know how to use is ActionListeners so forgive me for not knowing how. To start with, I would like to put on some reference.
Im working on an RFID Scanner Desktop App on java and EPOCH gave me this:
JSSC
The JSSC was able to provide me with the tools that I need to read my RFID but this time, I'm having issued on Implementing it on my application.
Here is my current Code:
First, Imports
import jssc.SerialPort;
import jssc.SerialPortEvent;
import jssc.SerialPortEventListener;
import jssc.SerialPortException;
Now for the class:
class SerialPortReader implements SerialPortEventListener {
SerialPort serialPort;
#Override
public void serialEvent(SerialPortEvent event) {
if(event.isRXCHAR()){//If data is available
if(event.getEventValue() == 10){//Check bytes count in the input buffer
//Read data, if 10 bytes available
try {
byte buffer[] = serialPort.readBytes(10);
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
}else if(event.isCTS()){//If CTS line has changed state
if(event.getEventValue() == 1){//If line is ON
System.out.println("CTS - ON");
}
else {
System.out.println("CTS - OFF");
}
}else if(event.isDSR()){///If DSR line has changed state
if(event.getEventValue() == 1){//If line is ON
System.out.println("DSR - ON");
}else {
System.out.println("DSR - OFF");
}
}
}
}
public class TestRF extends javax.swing.JFrame implements SerialPortEventListener{
SerialPort serialPort;
public TestRF() {
initComponents();
setSerialPort();
}
public void setSerialPort(){
SerialPort serialPort = new SerialPort("COM7");
try {
serialPort.openPort();//Open serial port
serialPort.setParams(9600, 8, 1, 0);//Set params.
byte[] buffer = serialPort.readBytes(10);//Read 10 bytes from serial port
//serialPort.closePort();//Close serial port
serialPort.addEventListener(this);//Add SerialPortEventListener
}
catch (SerialPortException ex) {
System.out.println(ex);
}
}
and lastly, the abstract method.. (I dont know what this does to be honest and im picking up books right now.)
#Override
public void serialEvent(SerialPortEvent spe) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
to put things simple. I need to get my RFID to read and pass that value anywhere in my project. I even thought of trying to extend my JFrame classes to a class file but so far, no luck.
tutorials anyone?

You can create 2 threads. 1st thread read data from serial port (RFID) while 2nd thread handles task specific to application. Also consider using serial communication manager library for serial port communication in java.
Please share RFID hardware details so that we can think best application design to use it.

Handling a Biometric Fingerprint Attendance Device by using socket

I am trying to connect with a Biometric Fingerprint Attendance Device using a Java program. The device I am using is a Biocom Fingerprint attendance system. However, I am search and reading about that and I see the SDK could used which based on device type (which hard, not logical, moreover, it is not global solution!)
I research for a global standard on how to connect, send and retrieve data with a Fingerprint Device which again I wasn't lucky enough to find a clear solution. Currently, I tried to connect with the device by creating a Socket object (through Ethernet port) but also not executed with me. This open infinite loop problems on my head.
Is there any general, standard way to connect, send and retrieve data from such device using Java?
Can a Socket be considered as a solution for such problem?
If yes, what is wrong in my code below? What additional things more than the host IP and port number are needed to connect with the device?
The Socket code that used:
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.net.UnknownHostException;
public class Requester {
Socket requestSocket;
ObjectOutputStream out;
ObjectInputStream in;
String message;
Requester() {
}
void run() throws IOException {
try {
// 1. creating a socket to connect to the server
requestSocket = new Socket("192.168.0.19", 4370);
System.out.println("Connected to given host in port 4370");
// 2. get Input and Output streams
in = new ObjectInputStream(requestSocket.getInputStream());
// 3: Communicating with the server
String line;
while (true) {
line = in.readLine();
if (line != null) {
System.out.println(line);
}
}
} catch (UnknownHostException unknownHost) {
System.err.println("You are trying to connect to an unknown host!");
} catch (IOException ioException) {
ioException.printStackTrace();
} catch (Exception Exception) {
Exception.printStackTrace();
} finally {
in.close();
requestSocket.close();
}
}
void sendMessage(String msg) {
try {
out.writeObject(msg);
out.flush();
System.out.println("client: " + msg);
} catch (IOException ioException) {
ioException.printStackTrace();
}
}
public static void main(String args[]) throws IOException {
Requester client = new Requester();
client.run();
}
}
This image may give more details:

You don't need the ObjectInputStream. Just use the InputStream you get from requestSocket.getInputStream().
Alternatively use a terminal programm like putty to connect to your device. This requires no coding.

Biocom Biometrics are ZKTeco devices. ZkTeco devices are launched only with windows SDK. You can download the SDK from https://www.zkteco.com/en/download_catgory.html and use the DLL in java which can run only on Windows platorm. For HTTP communication, to work in any platform through any language, refer http://camsunit.com/application/zk-teco-essl-api-integration.html

Send a String to serial port as a command for embedded device

I am working on a project that involves an embedded device. I am expected to send a command to this device. This command is a string: "LAMP1_ON\r\n";
I am using RXTX with java and sending the data via serial port. But when i send the String command, the device receives "AMP_N" and some other scattered string.
I have no idea why it is so, and how i can fix it.
My code is below:
public class SerialWriter implements Runnable {
OutputStream out;
String str;
public SerialWriter(OutputStream out, String str) {
this.out = out;
this.str = str;
}
public void run() {
try {
byte[] array = this.str.getBytes();
this.out.write(array);
this.out.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}
I expect to send the string to the port via the write method. It works but it doesn't send the exact String that is contained in this.str instead it sends "AMP_N" and "AMP" and scattered Strings

I have seen the problem. I didn't set the FLOWCONTROL property correctly. Thank you. This code works fine
serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
serialPort.setFlowControlMode(SerialPort.FLOWCONTROL_NONE);

Java RXTX not sending data

I'm trying to make a Java interface to send some AT commands to a GPRS Module.
I already had a working interface on Processing, but I migrated to pure Java because I find it easier to make graphic interfaces.
The Processing program sends data over serial to COM#. COM# is an Arduino with a GPRS Shield. All the Arduino Code does is pass the data received to the GPRS module and viceversa:
void loop(){
if (GPRS.available())
{
while(GPRS.available())
{
buffer[count++]=GPRS.read();
if(count == 64)break;
}
Serial.write(buffer,count);
clearBufferArray();
count = 0;
}
if (Serial.available()){
delay(100);
while(Serial.available()){
GPRS.write(Serial.read());
}
}
}
So I know that works fine because I've tested it using the Processing interface, and an external tool called SSCOM and all the comands are interpreted correctly.
Now the problem is, that when I tried to make the interface on java, using RXTX, it's not working at all. I'm not getting any errors on the console, and the only data I'm receiving on the Arduino is ÿ (char 255) each time I run java, and it's being sent when opening the port, not when writing to the serial port.
Here's the SerialHandlerclass I'm using. I found it around the web.
import gnu.io.CommPortIdentifier;
import gnu.io.NoSuchPortException;
import gnu.io.PortInUseException;
import gnu.io.SerialPort;
import gnu.io.UnsupportedCommOperationException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class SerialPortHandler {
private SerialPort serialPort;
private OutputStream outStream;
private InputStream inStream;
public void connect(String portName) throws IOException, PortInUseException, NoSuchPortException {
try {
// Obtain a CommPortIdentifier object for the port you want to open
CommPortIdentifier portId =
CommPortIdentifier.getPortIdentifier(portName);
// Get the port's ownership
serialPort =
(SerialPort) portId.open("Demo application", 5000);
// Set the parameters of the connection.
setSerialPortParameters();
// Open the input and output streams for the connection. If they won't
// open, close the port before throwing an exception.
outStream = serialPort.getOutputStream();
inStream = serialPort.getInputStream();
} catch (NoSuchPortException e) {
throw new IOException(e.getMessage());
} catch (PortInUseException e) {
throw new IOException(e.getMessage());
} catch (IOException e) {
serialPort.close();
throw e;
}
}
/**
* Get the serial port input stream
* #return The serial port input stream
*/
public InputStream getSerialInputStream() {
return inStream;
}
/**
* Get the serial port output stream
* #return The serial port output stream
*/
public OutputStream getSerialOutputStream() {
return outStream;
}
/**
* Sets the serial port parameters
*/
private void setSerialPortParameters() throws IOException {
int baudRate = 19200;
try {
serialPort.setSerialPortParams(
baudRate,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
serialPort.setFlowControlMode(
SerialPort.FLOWCONTROL_NONE);
} catch (UnsupportedCommOperationException ex) {
throw new IOException("Unsupported serial port parameter");
}
}
}
And here's my main class:
public class Main {
SerialPortHandler serial = new SerialPortHandler();
serial.connect("COM3");
OutputStream serialOut = serial.getSerialOutputStream();
String s = "AT+CPOWD=0\r\n";
serialOut.write(s.getBytes());
serialOut.flush();
}
}
rxtxSerial.dll and RXTXcomm.jar are in jre\bin and jre\lib\ext respectively.
I can't find the problem, like I said, I don't get any errors or warnings anywhere.
I'm using NetBeans 7.3.1, JDK 1.7 and Windows 8.1 x64.
I also tried using jSSC but I get the same results.

I solved the problem. It wasn't the jSSC or RXTX library.
PeterMmm was right, I needed a delay, but I needed it on my java program.
When I was testing communication, I was opening the port and sending data right away. The problem is Arduino by default resets when a connection is established, so the Arduino wasn't ready to process it.
A couple days ago, I decided to try again, with jSSC, but this time, the java program asked for an input to send through the serial port, leaving time for Arduino to boot. Arduino successfully received anything I typed.
Now that I implemented serial communication on the user interface I was developing, everything runs smoothly.