driver=com.sun.comm.Win32Driver

System.setSecurityManager(null);

String driverName = "com.sun.comm.Win32Driver"; // or get as a JNLP property
CommDriver commDriver = (CommDriver)Class.forName(driverName).newInstance();
commDriver.initialize();

import javax.comm.*;
import java.util.*;
...
//
// Platform specific port name, here= a Unix name
//
// NOTE: On at least one Unix JavaComm implementation JavaComm 
//    enumerates the ports as "COM1" ... "COMx", too, and not
//    by their Unix device names "/dev/tty...". 
//    Yet another good reason to not hard-code the wanted
//    port, but instead make it user configurable.
//
String wantedPortName = "/dev/ttya";
 //
// Get an enumeration of all ports known to JavaComm
//
Enumeration portIdentifiers = CommPortIdentifier.getPortIdentifiers();
//
// Check each port identifier if 
//  (a) it indicates a serial (not a parallel) port, and
//  (b) matches the desired name.
//
CommPortIdentifier portId = null; // will be set if port found
while (portIdentifiers.hasMoreElements())
{
  CommPortIdentifier pid = (CommPortIdentifier) portIdentifiers.nextElement();
  if(pid.getPortType() == CommPortIdentifier.PORT_SERIAL &&
    pid.getName().equals(wantedPortName)) 
  {
    portId = pid;
    break;
  }
}
if(portId == null)
{
  System.err.println("Could not find serial port " + wantedPortName);
  System.exit(1);
}
//
// Use port identifier for acquiring the port
//
...

注意：

JavaComm會(huì)從與其綁定的特定平臺(tái)相關(guān)的驅(qū)動(dòng)中獲得一個(gè)默認(rèn)的可訪問串口標(biāo)識(shí)列表。這個(gè)列表實(shí)際上不能通過JavaComm進(jìn)行配置。方法CommPortIdentifier.addPortName()是有誤導(dǎo)性的，因?yàn)轵?qū)動(dòng)類是與平臺(tái)相關(guān)的，而且它們的實(shí)現(xiàn)不是公共API的組成部分。依賴于驅(qū)動(dòng)，這個(gè)端口列表可能會(huì)在驅(qū)動(dòng)中進(jìn)行配置/擴(kuò)展。所以，如果JavaComm沒有找到某一特定端口，對(duì)驅(qū)動(dòng)進(jìn)行一些改動(dòng)有時(shí)會(huì)有所幫助。

某端口標(biāo)識(shí)符一旦被找到，就可以用它取得期望的端口：

//
// Use port identifier for acquiring the port
//
SerialPort port = null;
try {
  port = (SerialPort) portId.open(
    "name", // Name of the application asking for the port 
    10000  // Wait max. 10 sec. to acquire port
  );
} catch(PortInUseException e) {
  System.err.println("Port already in use: " + e);
  System.exit(1);
}
//
// Now we are granted exclusive access to the particular serial
// port. We can configure it and obtain input and output streams.
//
...

import java.io.*;
...
//
// Set all the params. 
// This may need to go in a try/catch block which throws UnsupportedCommOperationException
//
port.setSerialPortParams(
  115200,
  SerialPort.DATABITS_8,
  SerialPort.STOPBITS_1,
  SerialPort.PARITY_NONE);
//
// Open the input Reader and output stream. The choice of a
// Reader and Stream are arbitrary and need to be adapted to
// the actual application. Typically one would use Streams in
// both directions, since they allow for binary data transfer,
// not only character data transfer.
//
BufferedReader is = null; // for demo purposes only. A stream would be more typical.
PrintStream  os = null;
try {
 is = new BufferedReader(new InputStreamReader(port.getInputStream()));
} catch (IOException e) {
 System.err.println("Can't open input stream: write-only");
 is = null;
}
//
// New Linux systems rely on Unicode, so it might be necessary to
// specify the encoding scheme to be used. Typically this should
// be US-ASCII (7 bit communication), or ISO Latin 1 (8 bit
// communication), as there is likely no modem out there accepting
// Unicode for its commands. An example to specify the encoding
// would look like:
//
//   os = new PrintStream(port.getOutputStream(), true, "ISO-8859-1");
//
os = new PrintStream(port.getOutputStream(), true);
 //
// Actual data communication would happen here
// performReadWriteCode();
//
//
// It is very important to close input and output streams as well
// as the port. Otherwise Java, driver and OS resources are not released.
//
if (is != null) is.close();
if (os != null) os.close();
if (port != null) port.close();

// Write to the output 
os.print("AT");
os.print("\r\n"); // Append a carriage return with a line feed

is.readLine(); // First read will contain the echoed command you sent to it. In this case: "AT"
is.readLine(); // Second read will remove the extra line feed that AT generates as output

// Read the response
String response = is.readLine(); // if you sent "AT" then response == "OK"

import javax.comm.*;
 
/**
 * Listener to handle all serial port events.
 *
 * NOTE: It is typical that the SerialPortEventListener is implemented
 *    in the main class that is supposed to communicate with the
 *    device. That way the listener has easy access to state information
 *    about the communication, e.g. when a particular communication
 *    protocol needs to be followed.
 *
 *    However, for demonstration purposes this example implements a
 *    separate class.
 */ 
class SerialListener implements SerialPortEventListener {
 
  /**
   * Handle serial events. Dispatches the event to event-specific
   * methods.
   * @param event The serial event
   */
  @Override
  public void serialEvent(SerialPortEvent event){
 
    //
    // Dispatch event to individual methods. This keeps this ugly
    // switch/case statement as short as possible.
    //
    switch(event.getEventType()) {
      case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
        outputBufferEmpty(event);
        break;
 
      case SerialPortEvent.DATA_AVAILABLE:
        dataAvailable(event);
        break;
 
/* Other events, not implemented here ->
      case SerialPortEvent.BI:
        breakInterrupt(event);
        break;
 
      case SerialPortEvent.CD:
        carrierDetect(event);
        break;
 
      case SerialPortEvent.CTS:
        clearToSend(event);
        break;
 
      case SerialPortEvent.DSR:
        dataSetReady(event);
        break;
 
      case SerialPortEvent.FE:
        framingError(event);
        break;
 
      case SerialPortEvent.OE:
        overrunError(event);
        break;
 
      case SerialPortEvent.PE:
        parityError(event);
        break;
      case SerialPortEvent.RI:
        ringIndicator(event);
        break;
<- other events, not implemented here */
 
    }
  }
 
  /**
   * Handle output buffer empty events.
   * NOTE: The reception of this event is optional and not
   *    guaranteed by the API specification.
   * @param event The output buffer empty event
   */
  protected void outputBufferEmpty(SerialPortEvent event) {
    // Implement writing more data here
  }
 
  /**
   * Handle data available events.
   *
   * @param event The data available event
   */
  protected void dataAvailable(SerialPortEvent event) {
    // implement reading from the serial port here
  }
}

SerialPort port = ...;
...
//
// Configure port parameters here. Only after the port is configured it
// makes sense to enable events. The event handler might be called immediately
// after an event is enabled.
...
 
//
// Typically, if the current class implements the SerialEventListener interface
// one would call
//
//    port.addEventListener(this);
//
// but for our example a new instance of SerialListener is created:
//
port.addEventListener(new SerialListener());
 
//
// Enable the events we are interested in
//
port.notifyOnDataAvailable(true);
port.notifyOnOutputEmpty(true);
 
/* other events not used in this example ->
port.notifyOnBreakInterrupt(true);
port.notifyOnCarrierDetect(true);
port.notifyOnCTS(true);
port.notifyOnDSR(true);
port.notifyOnFramingError(true);
port.notifyOnOverrunError(true);
port.notifyOnParityError(true);
port.notifyOnRingIndicator(true);
<- other events not used in this example */

/**
 * Synchronized ring buffer. 
 * Suitable to hand over data from one thread to another.
 **/
public class RingBuffer {
  /** internal buffer to hold the data **/
  protected byte buffer[];
  /** size of the buffer **/
  protected int size;
  /** current start of data area **/
  protected int start;
  /** current end of data area **/
  protected int end;
 
  /**
   * Construct a RingBuffer with a default buffer size of 1k.
   */
  public RingBuffer() {
     this(1024);
  }
  /**
   * Construct a RingBuffer with a certain buffer size.
   * @param size  Buffer size in bytes
   */
  public RingBuffer(int size) {
     this.size = size;
     buffer = new byte[size];
     clear();
  }
  /**
   * Clear the buffer contents. All data still in the buffer is lost.
   */
  public void clear() {
    // Just reset the pointers. The remaining data fragments, if any,
    // will be overwritten during normal operation.
    start = end = 0;
  }
  /**
   * Return used space in buffer. This is the size of the
   * data currently in the buffer.
   * <p>
   * Note: While the value is correct upon returning, it
   * is not necessarily valid when data is read from the 
   * buffer or written to the buffer. Another thread might
   * have filled the buffer or emptied it in the mean time.
   *
   * @return currently amount of data available in buffer
   */
  public int data() {
     return start <= end
           ? end - start
           : end - start + size;
  }
  /**
   * Return unused space in buffer. Note: While the value is
   * correct upon returning, it is not necessarily valid when
   * data is written to the buffer or read from the buffer.
   * Another thread might have filled the buffer or emptied
   * it in the mean time.
   *
   * @return currently available free space
   */
  public int free() {
     return start <= end
           ? size + start - end
           : start - end;
  }
  /**
   * Write as much data as possible to the buffer.
   * @param data  Data to be written
   * @return    Amount of data actually written
   */
  int write(byte data[]) {
    return write(data, 0, data.length); 
  }
  /**
   * Write as much data as possible to the buffer.
   * @param data  Array holding data to be written
   * @param off  Offset of data in array
   * @param n   Amount of data to write, starting from .
   * @return    Amount of data actually written
   */
  int write(byte data[], int off, int n) {
    if(n <= 0) return 0;
    int remain = n;
    // @todo check if off is valid: 0= <= off < data.length; throw exception if not
    int i = Math.min(remain, (end < start ? start : buffer.length) - end);
    if(i > 0) {
       System.arraycopy(data, off, buffer, end, i);
       off  += i;
       remain -= i;
       end  += i;
    }
    i = Math.min(remain, end >= start ? start : 0);
    if(i > 0 ) {
       System.arraycopy(data, off, buffer, 0, i);
       remain -= i;
       end = i;
    }
    return n - remain;
  }
 
  /**
   * Read as much data as possible from the buffer.
   * @param data  Where to store the data
   * @return    Amount of data read
   */
  int read(byte data[]) {
    return read(data, 0, data.length); 
  }
  /**
   * Read as much data as possible from the buffer.
   * @param data  Where to store the read data
   * @param off  Offset of data in array
   * @param n   Amount of data to read
   * @return    Amount of data actually read
   */
  int read(byte data[], int off, int n) {
    if(n <= 0) return 0;
    int remain = n;
    // @todo check if off is valid: 0= <= off < data.length; throw exception if not
    int i = Math.min(remain, (end < start ? buffer.length : end) - start);
    if(i > 0) {
       System.arraycopy(buffer, start, data, off, i);
       off  += i;
       remain -= i;
       start += i;
       if(start >= buffer.length) start = 0;
    }
    i = Math.min(remain, end >= start ? 0 : end);
    if(i > 0 ) {
       System.arraycopy(buffer, 0, data, off, i);
       remain -= i;
       start = i;
    }
    return n - remain;
  }
}

  RingBuffer dataBuffer = ... ;
  /**
  * Handle output buffer empty events.
  * NOTE: The reception is of this event is optional and not
  *    guaranteed by the API specification.
  * @param event The output buffer empty event
  */
  protected void outputBufferEmpty(SerialPortEvent event) {
  }

import javax.comm.*;
...
InputStream is = port.getInputStream();
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("out.dat"));
/**
 * Listen to port events
 */ 
class FileListener implements SerialPortEventListener {

  /**
   * Handle serial event.
   */
  void serialEvent(SerialPortEvent e) {
    SerialPort port = (SerialPort) e.getSource();

    //
    // Discriminate handling according to event type
    //
    switch(e.getEventType()) {
    case SerialPortEvent.DATA_AVAILABLE:

      //
      // Move all currently available data to the file
      //
      try {
         int c;
         while((c = is.read()) != -1) {
            out.write(c);
         }
      } catch(IOException ex) {
         ...
      }
      break;
    case ...:
      ...
      break;
    ...
    }
    if (is != null) is.close();
    if (port != null) port.close();
  }