serialbean.java

用Java在Windows下实现串口全双工通讯的例子

package serial;

import java.io.*;
import javax.comm.*;

/**
 * 
 * This bean provides some basic functions to implement full dulplex information
 * exchange through the srial port.
 * 
 */
public class SerialBean {
	static String PortName;
	CommPortIdentifier portId;
	SerialPort serialPort;
	static OutputStream out;
	static InputStream in;
	SerialBuffer SB;
	ReadSerial RT;

	/**
	 * 
	 * Constructor
	 * 
	 * @param PortID
	 *            the ID of the serial to be used. 1 for COM1, 2 for COM2, etc.
	 * 
	 */
	public SerialBean(int PortID) {
		PortName = "COM" + PortID;
	}

	/**
	 * 
	 * This function initialize the serial port for communication. It startss a
	 * thread which consistently monitors the serial port. Any signal capturred
	 * from the serial port is stored into a buffer area.
	 * 
	 */
	public int Initialize() {
		int InitSuccess = 1;
		int InitFail = -1;
		try {
			portId = CommPortIdentifier.getPortIdentifier(PortName);
			try {
				serialPort = (SerialPort) portId.open("Serial_Communication",
						5000);
			} catch (PortInUseException e) {
				return InitFail;
			}
			// Use InputStream in to read from the serial port, and OutputStream
			// out to write to the serial port.
			try {
				in = serialPort.getInputStream();
				out = serialPort.getOutputStream();
			} catch (IOException e) {
				return InitFail;
			}
			// Initialize the communication parameters to 9600, 8, 1, none.
			try {
				serialPort.setSerialPortParams(9600, SerialPort.DATABITS_8,
						SerialPort.STOPBITS_1, SerialPort.PARITY_NONE);
			} catch (UnsupportedCommOperationException e) {
				return InitFail;
			}
		} catch (NoSuchPortException e) {
			return InitFail;
		}
		// when successfully open the serial port, create a new serial buffer,
		// then create a thread that consistently accepts incoming signals from
		// the serial port. Incoming signals are stored in the serial buffer.
		SB = new SerialBuffer();
		RT = new ReadSerial(SB, in);
		RT.start();
		// return success information
		return InitSuccess;
	}

	/**
	 * 
	 * This function returns a string with a certain length from the incomin
	 * messages.
	 * 
	 * @param Length
	 *            The length of the string to be returned.
	 * 
	 */
	public String ReadPort(int Length) {
		String Msg = "";
		Msg = SB.GetMsg(Length);
		return Msg;
	}

	/**
	 * 
	 * This function sends a message through the serial port.
	 * 
	 * @param Msg
	 *            The string to be sent.
	 * 
	 */
	public void WritePort(String Msg) {
		try {
			for (int i = 0; i < Msg.length(); i++)
				out.write(Msg.charAt(i));
		} catch (IOException e) {
		}
	}

	/**
	 * 
	 * This function closes the serial port in use.
	 * 
	 */
	@SuppressWarnings("deprecation")
	public void ClosePort() {
		RT.stop();
		serialPort.close();
	}
}