一些关于串口通讯的问题，希望有人帮我解答

Question

怎么可能读不到数据呢?
你试试comm包的那些例子程序好了,我就是参考那些例子来做的,
程序都是没有问题的.

Answer 1

import java.io.*;
import java.util.*;
import javax.comm.*;public class Dial_up implements SerialPortEventListener{
    static Enumeration portList;
    static CommPortIdentifier portId;
    static String messageString = "Hello, world!\n";
    static SerialPort serialPort;
    static OutputStream outputStream;
    static InputStream inputStream;    public static void main(String[] args) {
        portList = CommPortIdentifier.getPortIdentifiers();        while (portList.hasMoreElements()) {
            portId = (CommPortIdentifier) portList.nextElement();
            if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
                if (portId.getName().equals("COM1")) {
                //if (portId.getName().equals("/dev/term/a")) {
                    try {
                        serialPort = (SerialPort)
                            portId.open("SimpleWriteApp", 2000);
                    } catch (PortInUseException e) {}                    try {
                        outputStream = serialPort.getOutputStream();
                    } catch (IOException e) {}                   try {
                     inputStream = serialPort.getInputStream();
                   } catch (IOException e) {}                    try {
                        serialPort.setSerialPortParams(9600,
                            SerialPort.DATABITS_8,
                            SerialPort.STOPBITS_1,
                            SerialPort.PARITY_NONE);
                    } catch (UnsupportedCommOperationException e) {}                    try {
                       serialPort.addEventListener(new SerialListener1());
                    } catch (TooManyListenersException e) {}
                    serialPort.notifyOnDataAvailable(true);                    try {
                        outputStream.write(messageString.getBytes());
                    } catch (IOException e) {}
                }
            }//end of if COM1
        }//end of while
    }//end of main    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:
            byte[] readBuffer = new byte[20];            try {
                while (inputStream.available() > 0) {
                    int numBytes = inputStream.read(readBuffer);
                }
                System.out.print(new String(readBuffer));
            } catch (IOException e) {}
            break;
        }
    }
}//end of class