Communicating with Arduino in Java [closed] - arduino

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Closed 9 years ago.
How do I make communications go between Arduino Uno and a Java app?
I've found Arduino and Java, but that's not clear to me.

Answer 1

Ok, I'll modify the same code to help you understand. (I'll remove the listener and add a substitution, which is not good. You should use the listener)
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;
public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
private static final String PORT = "COM32";
private InputStream input;
private OutputStream output;
private static final int TIME_OUT = 2000;
private static final int DATA_RATE = 9600;
public void initialize() {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
if (currPortId.getName().equals(PORT)) {
portId = currPortId;
break;
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = serialPort.getInputStream();
output = serialPort.getOutputStream();
} catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.start();
}
public void start() throws IOException {
initialize();
System.out.println("Started");
byte[] readBuffer = new byte[400];
while (true) {
int availableBytes = input.available();
if (availableBytes > 0) {
// Read the serial port
input.read(readBuffer, 0, availableBytes);
// Print it out
System.out.print(new String(readBuffer, 0, availableBytes));
}
}
}
}
Run this and load a code to Arduino which write to the serial. Then those values will be displayed by the program. (you may need to change the PORT accordingly)