CommPortIdentifier.getPortIdentifiers is empty

问题

I am building a simple application that communicates through Serial Port using the Java Communication API javax.comm.

Here is some code in my java main method I wrote:

CommPortIdentifier cpi = null;
        Enumeration e = CommPortIdentifier.getPortIdentifiers();
        while (e.hasMoreElements()) {
            try {
                cpi = (CommPortIdentifier) e.nextElement();
            } catch (NoSuchElementException n) {

            }
            System.out.println(cpi.getName());
        }

Enumeration e is always empty even though I am connected to a COM 4 port when running this.

also, running this code:

portRead = CommPortIdentifier.getPortIdentifier("COM8");

cause the throw of NoSuchPortException

I think I have done the installation part correctly and placed the properties file, the win32com.dll file in the right places.

Do you know what the problem could be?

Thank You

回答1:

Make sure that win32com.dll (comes with javax.com) is in the jre\bin directory. Make sure javax.comm.properties (comes with javax.com) is in the jdk\lib directory.

回答2:

Remember always you need to add all the unzipped files from javax.comm.zip to jre

win32com.dll - jre/bin

comm.jar - jre/lib/ext

java.comm.properties - jre/lib (after adding this I found resolved exception problem )

回答3:

This works for me (I installed x86 jdk ) and followed the steps

Your problem is that windows could'nt communicate the right PORT to your JAVA Program.

You have to copy the right files in the right location by following this link.

http://kishor15389.blogspot.com/2011/05/how-to-install-java-communications.html

回答4:

Find port in which your device is working(Try power shell or hyper terminal to find all com ports try link)

来源：https://stackoverflow.com/questions/15955530/commportidentifier-getportidentifiers-is-empty

标签

java

serial-port

javax.comm