菜鸟求助，串口通信，又是NoSuchPortException
代码如下
import java.io.*;
import java.util.*;
import javax.comm.*;



public class Communication {

private static SerialPort serialPort;
private static String portName;
private static InputStream in;
private InputStream inputStream;


public static void main (String arg[]){
try{
CommPortIdentifier portId = CommPortIdentifier.getPortIdentifier(portName) ;

try {
serialPort = (SerialPort)portId.open("Serial_Communication",5000);
} catch (PortInUseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
serialPort. setSerialPortParams (4800,SerialPort.DATABITS_8,SerialPort.STOPBITS_1 ,SerialPort.PARITY_NONE);
try {
in = serialPort.getInputStream();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
catch (UnsupportedCommOperationException e)
{
System.out.println("UnsupportedCommOperation");
}
catch (NoSuchPortException e)
{
System.out.println("NoSuchPort");
}
System.out.println("done") ;
}

运行结果
NoSuchPort
done



鼠标放在CommPortIdentifier portId = CommPortIdentifier.getPortIdentifier(portName)上面，会提示
This element neither has attached source nor attached Javadoc and hence no Javadoc could be found.

求高手指教。。

[解决办法]
汗
portName没有进行初始化。那肯定就是空了。
[解决办法]