程序是这样的
import java.io.*;public class Help
{
   public static void main(String[] args)
   {               File OutFile = new File("SEND.txt");
               File ComPort = new File("COM2");
               char[] buf = new char [1000];               int c;               try
               {
                       FileReader in = new FileReader(OutFile);
                       FileWriter out = new FileWriter(ComPort);
                       int len = in.read(buf);
                       System.out.println(new String(buf,0,len));
                       System.out.println("kin is a genius");
                       while ((c = in.read()) != -1)
                               out.write(c);
                       in.close();
                       out.close();
               } catch (IOException e) {}       }
}运行之后不能正常输出,用print试验出来在in.read(buf)后的语句便不再执行,COM2改成COM1就能正常输出了,是什么原因?