import javax.comm.UnsupportedCommOperationException; //导入依赖的package包/类
/**
 * returns the port-name for a given serial-port-number for the running OS.
 *
 * @param portNr
 *            the port nnumber for which the portname should be generated
 * @return a string representing the port name
 * @throws UnsupportedCommOperationException
 *             if the Operating System is not known by the method
 */
static public String getSerialPortNameForOS(int portNr)
		throws UnsupportedCommOperationException {
	char letter[] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
			'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
			'w', 'x', 'y', 'z' };
	String os = System.getProperty("os.name");

	if ((portNr > 26) || (portNr < 1)) {
		throw new UnsupportedCommOperationException(
				"Serial port number must be between 1 and 26.");
	}

	if (os.equals("Linux")) {
		return "/dev/ttyS" + (portNr - 1);
	} else if (os.equals("SunOS")) {
		return "/dev/term/" + letter[portNr - 1];
	} else if (os.startsWith("Windows")) {
		return "COM" + portNr;
	} else {
		throw new UnsupportedCommOperationException(
				"ISOProtocol: Unknown Operating System.");
	}
}
 

import javax.comm.UnsupportedCommOperationException; //导入依赖的package包/类
private boolean setParams(SerialPort tmpPort, int B, int D, int P, int S){
    boolean success = true;
    
    switch (D){
        case 5: D=tmpPort.DATABITS_5;
        break;  
        case 6: D=tmpPort.DATABITS_6;
        break;  
        case 7: D=tmpPort.DATABITS_7;
        break;  
        case 8: D=tmpPort.DATABITS_8;
        break;  
        default: success=false; 
    }
    switch (P){           
        case 0: P=tmpPort.PARITY_NONE;
        break;  
        case 1: P=tmpPort.PARITY_EVEN;
        break;  
        case 2: P=tmpPort.PARITY_ODD;
        break;  
        case 3: P=tmpPort.PARITY_MARK;
        break;
        case 4: P=tmpPort.PARITY_SPACE;
        break;  
        default: success=false;
    }
    switch (S){
        case 1: S=tmpPort.STOPBITS_1;
        break;  
        case 2: S=tmpPort.STOPBITS_2;
        break;
        case 3: S=tmpPort.STOPBITS_1_5;
        break;  
        default: success=false;           
    }
    if(success) {
         try {tmpPort.setSerialPortParams(B,D,S,P);
         } catch (UnsupportedCommOperationException ex) {
             ex.printStackTrace();
             System.out.println("Cannot set port properties, please check your settings");
         }
    }
    return success;
}
 

import javax.comm.UnsupportedCommOperationException; //导入依赖的package包/类
/**
 * creates a new instance and opens the com-port.
 *
 * @param portNr
 *            the n-th serial port in the system starting with 1.
 * @param timeout
 *            the maximal time in milliseconds that the sendRequest method
 *            blocks, before throwing an exception.
 * @param baud
 *            the baud rate for the serial port communication.
 * @param databits
 *            the databits for the serial port communication.
 * @param stopbits
 *            the stopbits for the serial port communication.
 * @param parity
 *            then parity for the serial port communication.
 * @throws UnsupportedCommOperationException
 *             if setting port parameters fails
 * @throws PortInUseException
 *             if opening port fails
 * @throws IOException
 *             if geting in-/outputstream fails or if there are too many
 *             listeners for this port
 */
public ISOProtocol(int portNr, long timeout, int baud, int databits,
		int stopbits, int parity) throws UnsupportedCommOperationException,
		PortInUseException, IOException {
	this.timeout = timeout;
	String portName = getSerialPortNameForOS(portNr);
	openPort(portName, baud, databits, stopbits, parity);
}