使用Java读取串口的程序

下是我写的用Java读取串口的程序。这个程序里面还有一些问题，也希望有经验的网友能够给我提点意见。

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。
------------------------------------------
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();
}
}
---------------------------------------------
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);
}

}
}
-----------------------------------------------
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) {}
}
}
------------------------------------------------
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();
}
}
-------------------------------------------------
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());
}
}
}
-----------------------------------------------
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. *