[SOLVED] Modbus TCP Master error

[Aurelien]

Hello everybody,

I want to use Modbus4J rather than Jamod. I use Modbus4J version 3.0.0.

I'm trying to test the smallest possible example :

package testModbus;

import com.serotonin.modbus4j.ModbusFactory;
import com.serotonin.modbus4j.ModbusMaster;
import com.serotonin.modbus4j.code.DataType;
import com.serotonin.modbus4j.ip.IpParameters;
import com.serotonin.modbus4j.locator.BaseLocator;

public class Main {

    public static void main(String[] args) throws Exception {
        IpParameters params = new IpParameters();
        params.setHost("localhost");
        params.setPort(502);
        
        ModbusFactory masterF = new ModbusFactory();
        
        ModbusMaster master = masterF.createTcpMaster(params, false);
        master.init();

        System.out.println(master.testSlaveNode(5));

        // Define the point locator.
        BaseLocator<Number> loc = BaseLocator.holdingRegister(1, 0, DataType.TWO_BYTE_INT_UNSIGNED);

        // Set the point value
        master.setValue(loc, 1800);

        // Get the point value
        System.out.println(master.getValue(loc));
    }
}

I have this error when I tryto execute the Java program :

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
	at com.serotonin.modbus4j.ip.tcp.TcpMaster.<init>(TcpMaster.java:57)
	at com.serotonin.modbus4j.ModbusFactory.createTcpMaster(ModbusFactory.java:69)
	at testModbus.Main.main(Main.java:18)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 3 more

With another bigger test, the error is the same.

I don't know where is the real problem with the code, or configuration, ... ?

Thanks you in advance for the help :-)
Aurélien, France

[phildunlap]

Hi Aurelien,

That looks to me like you need a log4j.xml file somewhere on your classpath at runtime. You can just add the "-cp /path/to/log4j.xml" to the invocation of your program.

[Aurelien]

Thanks ! :-D

I have found the solution.

It's necessary to add commons logging library.

Download :
http://commons.apache.org/proper/commons-logging/download_logging.cgi

[phildunlap]

Nice! Thanks for sharing the solution!