Posted on 2010-06-18 17:06
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心得體會
一、往串口寫數據
import java.io.*;
import javax.comm.*;
import java.util.*;
public class PortWriter
{
static Enumeration ports;
static CommPortIdentifier pID;
static OutputStream outStream;
SerialPort serPort;
static String messageToSend = "message!\n";
public PortWriter() throws Exception{
serPort = (SerialPort)pID.open("PortWriter",2000);
outStream = serPort.getOutputStream();
serPort.setSerialPortParams(9600, SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
}
public static void main(String[] args) throws Exception{
ports = CommPortIdentifier.getPortIdentifiers();
while(ports.hasMoreElements())
{
pID = (CommPortIdentifier)ports.nextElement();
System.out.println("Port " + pID.getName());
if (pID.getPortType() == CommPortIdentifier.PORT_SERIAL)
{
if (pID.getName().equals("COM1"))
{
PortWriter pWriter = new PortWriter();
System.out.println("COM1 found");
}
}
}
outStream.write(messageToSend.getBytes());
}
}
二、通過串口傳送文件：
import java.io.*;
import javax.comm.*;
public class PrintFile {
public static void main(String args[]) throws Exception {
if (args.length != 2) {
System.err.println("usage : java PrintFile port file");
System.err.println("sample: java PrintFile LPT1 sample.prn");
System.exit(-1);
}
String portname = args[0];
String filename = args[1];
// Get port
CommPortIdentifier portId = CommPortIdentifier
.getPortIdentifier(portname);
// Open port
// Requires owner name and timeout
CommPort port = portId.open("Java Printing", 30000);
// Setup reading from file
FileInputStream fis = new FileInputStream(filename);
BufferedInputStream bis = new BufferedInputStream(fis);
// Setup output
OutputStream os = port.getOutputStream();
BufferedOutputStream bos = new BufferedOutputStream(os);
int c;
while ((c = bis.read()) != -1) {
bos.write(c);
}
// Close
bos.close();
bis.close();
port.close();
}
}
Below we have an example which sends a string to one serial port, receives it on the same port. You need a null-modem for this (just connect the RX and TX pins of your serial port to test this). In a production environment this example can be used as a template for sending and receiving data from e.g. a micro-controller board.
// derived from SUN's examples in the javax.comm package
import java.io.*;
import java.util.*;
//import javax.comm.*; // for SUN's serial/parallel port libraries
import gnu.io.*; // for rxtxSerial library
public class nulltest implements Runnable, SerialPortEventListener 
{
static CommPortIdentifier portId;
static CommPortIdentifier saveportId;
static Enumeration portList;
InputStream inputStream;
SerialPort serialPort;
Thread readThread;
static String messageString = "Hello, world!";
static OutputStream outputStream;
static boolean outputBufferEmptyFlag = false;
public static void main(String[] args) {
boolean portFound = false;
String defaultPort;
// determine the name of the serial port on several operating systems
String osname = System.getProperty("os.name","").toLowerCase();
if ( osname.startsWith("windows") ) {
// windows
defaultPort = "COM1";
} else if (osname.startsWith("linux")) {
// linux
defaultPort = "/dev/ttyS0";
} else if ( osname.startsWith("mac") ) {
// mac
defaultPort = "????";
} else {
System.out.println("Sorry, your operating system is not supported");
return;
}
if (args.length > 0) {
defaultPort = args[0];
}
System.out.println("Set default port to "+defaultPort);
// parse ports and if the default port is found, initialized the reader
portList = CommPortIdentifier.getPortIdentifiers();
while (portList.hasMoreElements()) {
portId = (CommPortIdentifier) portList.nextElement();
if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
if (portId.getName().equals(defaultPort)) {
System.out.println("Found port: "+defaultPort);
portFound = true;
// init reader thread
nulltest reader = new nulltest();
}
}
}
if (!portFound) {
System.out.println("port " + defaultPort + " not found.");
}
}
public void initwritetoport() {
// initwritetoport() assumes that the port has already been opened and
// initialized by "public nulltest()"
try {
// get the outputstream
outputStream = serialPort.getOutputStream();
} catch (IOException e) {}
try {
// activate the OUTPUT_BUFFER_EMPTY notifier
serialPort.notifyOnOutputEmpty(true);
} catch (Exception e) {
System.out.println("Error setting event notification");
System.out.println(e.toString());
System.exit(-1);
}
}
public void writetoport() {
System.out.println("Writing \""+messageString+"\" to "+serialPort.getName());
try {
// write string to serial port
outputStream.write(messageString.getBytes());
} catch (IOException e) {}
}
public nulltest() {
// initalize serial port
try {
serialPort = (SerialPort) portId.open("SimpleReadApp", 2000);
} catch (PortInUseException e) {}
try {
inputStream = serialPort.getInputStream();
} catch (IOException e) {}
try {
serialPort.addEventListener(this);
} catch (TooManyListenersException e) {}
// activate the DATA_AVAILABLE notifier
serialPort.notifyOnDataAvailable(true);
try {
// set port parameters
serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
} catch (UnsupportedCommOperationException e) {}
// start the read thread
readThread = new Thread(this);
readThread.start();
}
public void run() {
// first thing in the thread, we initialize the write operation
initwritetoport();
try {
while (true) {
// write string to port, the serialEvent will read it
writetoport();
Thread.sleep(1000);
}
} catch (InterruptedException e) {}
}
public void serialEvent(SerialPortEvent event) {
switch (event.getEventType()) {
case SerialPortEvent.BI:
case SerialPortEvent.OE:
case SerialPortEvent.FE:
case SerialPortEvent.PE:
case SerialPortEvent.CD:
case SerialPortEvent.CTS:
case SerialPortEvent.DSR:
case SerialPortEvent.RI:
case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
break;
case SerialPortEvent.DATA_AVAILABLE:
// we get here if data has been received
byte[] readBuffer = new byte[20];
try {
// read data
while (inputStream.available() > 0) {
int numBytes = inputStream.read(readBuffer);
}
// print data
String result = new String(readBuffer);
System.out.println("Read: "+result);
} catch (IOException e) {}
break;
}
}
}
http://edn.embarcadero.com/article/31915
http://www.particle.kth.se/~lindsey/JavaCourse/Book/Part3/Chapter23/serialPortDemo.html
http://radio.javaranch.com/frank/2004/03/22/1079951422000.html
http://www.velocityreviews.com/forums/t144781-com-port-communication.html