MILY: 宋体; mso-bidi-font-size: 10.0pt"> 

这个简单的程序包括以下文件：

       IMU.java (主程序)
       ReadBuffer.java (从缓冲区读取一个消息)
       ReadSerial.java (读取串口数据并放入缓冲区)
       SerialBuffer.java (缓冲区)
       WriteSerial.java (不断的往串口送星号'*')

测试程序：

       SendCom.java (将一个数据文件往串口发送)
       SEND.TXT (供测试用的数据文件)

在这个通讯程序中使用了一个简单的协议，既不同的消息之间用星号'*'作为分隔。这个程序中的问题是ReadSerial进程和WriteSerial进程不能够同时启动，出错信息是不能够打开串口，因为同样一个串口不能够同时被打开两次(在ReadSerial中声明了FileReader

测试程序：

       SendCom.java (将一个数据文件往串口发送)
       SEND.TXT (供测试用的数据文件)

在这个通讯程序中使用了一个简单的协议，既不同的消息之间用星号'*'作为分隔。这个程序中的问题是ReadSerial进程和WriteSerial进程不能够同时启动，出错信息是不能够打开串口，因为同样一个串口不能够同时被打开两次(在ReadSerial中声明了FileReader和在WriteSerial中声明了FileWriter)。这样是不能够实现全双工通讯的。不知道有没有做过的大侠能够讲讲处理的办法。

/*
*
* IMU.java 1.0
* Main Program for Serial Communication
*
* Created: March 27, 2001
*
* Author : Qingye Jiang (John)
* American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
* qjiang@tsinghua.edu
*
*/

import java.io.*;

class IMU
{
       public static void main(String[] args)
       {
               //TO DO: Add your JAVA codes here

               File ComPort = new File("COM1");

       SerialBuffer SB = new SerialBuffer();
       ReadSerial r1 = new ReadSerial(SB, ComPort);
       ReadBuffer r2 = new ReadBuffer(SB);
       WriteSerial r3 = new WriteSerial(ComPort);

       r1.start();
       r2.start();
       r3.start();
   }
}

/*
*
* ReadBuffer.java 1.0
* Program to Read the Serial Buffer
*
* Created: March 27, 2001
*
* Author : Qingye Jiang (John)
* American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
* qjiang@tsinghua.edu

*
*/

import java.io.*;

public class ReadBuffer extends Thread
{
   private SerialBuffer ComBuffer;

   public ReadBuffer(SerialBuffer SB)
   {
       ComBuffer = SB;
   }

   public void run()
   {
               String Msg;

       while (true)
       {
               Msg = ComBuffer.GetMsg();
               System.out.println(Msg);
       }

   }
}

/*
*
* ReadSerial.java 1.0
* Program to read characters from the serial port and put it
* to the buffer
*
* Created: March 27, 2001
*
* Author : Qingye Jiang (John)
* American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
*       qjiang@tsinghua.edu
*
*/

import java.io.*;

public class ReadSerial extends Thread
{
   private SerialBuffer ComBuffer;
   private File ComPort;

   public ReadSerial(SerialBuffer SB, File Port)
   {
       ComBuffer = SB;
       ComPort = Port;
   }

   public void run()
   {
               int c;
               try
               {
                       FileReader in = new FileReader(ComPort);
               while (true)
           {
               c = in.read();
               ComBuffer.PutChar(c);
           }
               try
               {
                       FileReader in = new FileReader(ComPort);
               while (true)
           {
               c = in.read();

               ComBuffer.PutChar(c);
           }
       } catch (IOException e) {}
   }
}


/*
*
* SerialBuffer.java 1.0
* Class that implements the serial buffer
*
* Created: March 27, 2001
*
* Author : Qingye Jiang (John)
*   American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
* qjiang@tsinghua.edu

*
*/

public class SerialBuffer
{
   private String Content = "";
   private String CurrentMsg, TempContent;
   private boolean available = false;

   public synchronized String GetMsg()
   {
       int SepMark;

       if ((SepMark = Content.indexOf('*')) == -1)

{
               available = false;
               while (available == false)
               {
               try
               {
                   wait();
               } catch (InterruptedException e) { }
               }
               SepMark = Content.indexOf('*');
       }

       CurrentMsg = Content.substring(0, SepMark);
       TempContent = Content.substring(SepMark+1);
       Content = TempContent;
       notifyAll();
       return CurrentMsg;
   }

   public synchronized void PutChar(int c)
   {
       Character d = new Character((char) c);
       Content = Content.concat(d.toString());
       if (c == '*')
       {
               available = true;
       }
       notifyAll();
   }
}


/*
*
* WriteSerial.java 1.0
* Program to send a character to the serial port
*
* Created: March 27, 2001
*
* Author : Qingye Jiang (John)
* American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
* qjiang@tsinghua.edu
*
*/

import java.io.*;

public class WriteSerial extends Thread
{
   private SerialBuffer ComBuffer;
   private File ComPort;

   public WriteSerial(File Port)
   {
       ComPort = Port;
   }

   public void run()
   {
               int c;
               try
               {
                       FileWriter out = new FileWriter(ComPort);
               while (true)
           {
               out.write('*');
           }
       } catch (IOException e)
       {
               System.out.println(e.getMessage());
       }
   }
}
/*
*
* SendCom.java 1.0
*
* Project: Java Based Information Exchange Support System
* Onboard Plug-in System
* Sending data through serial port
*
* Created: March 15, 2001
*
* Author : Qingye Jiang (John)
* American GNC Corporation
* 888 Easy St, Simi Valley CA 93065-1812
*
* Contact: (805) 582-0582 (Tel), (805) 582-0098 (Fax)
*
*/

import java.io.*;

public class SendCom
{
   public static void main(String[] args)
   {

               File OutFile = new File("SEND.TXT");
               File ComPort = new File("COM2");

               int c;

               try
               {
                       FileReader in = new FileReader(OutFile);
                       FileWriter out = new FileWriter(ComPort);
                       while ((c = in.read()) != -1)
                               out.write(c);
                       in.close();
                       out.close();
               } catch (IOException e) {}

       }
}

SEND.TXT*

This is a sample of the data file for program testing. *

It should be in the same directory as the SendCom.class file.*

When you run this sample program, connect your COM1 and COM2 with a
serial cable so that you can test this program on one machine. If
you have two machines, you can connect the two machine via a serial
cable and test it. Modified the definition of ComPort in the program
if necessary. *

Thank you for testing this program. If you have any suggestions please
kindly let me know. *