Logging
Logging support
As from Struts 2.5 version, the logging layer is deprecated and Struts uses Log4j2 The logging layer will be dropped with the next major release.
Note: support for a custom logging layer has been removed in Struts 6.x
XWork provides its own layer to support logging - it allows to use many different implementations.
Currently XWork provides support for the following libraries (in that order base on classpath discovery):
Usage
To use given type of library add it as a Maven dependency or drop into WEB-INF/lib folder. XWork LoggerFactory class will use given logging provider if available.
To add logging to your application simply declare a Logger as follow:
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
public class MyAction {
private static final Logger LOG = LoggerFactory.getLogger(MyAction.class);
private String userName;
public String execute() {
LOG.debug("MyAction executed with UserName [#0]", userName);
return "success";
}
// getter / setter
}
Implementing my own factory
You plug in your own logging solution, simple extend LoggerFactory class and provide a delegate which implements Logger interface, like below:
JdkLoggerFactory which adds support for JDK logging
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
/**
* Creates jdk loggers
*/
public class JdkLoggerFactory extends LoggerFactory {
@Override
protected Logger getLoggerImpl(Class<?> cls) {
return new JdkLogger(java.util.logging.Logger.getLogger(cls.getName()));
}
@Override
protected Logger getLoggerImpl(String name) {
return new JdkLogger(java.util.logging.Logger.getLogger(name));
}
}
JdkLogger is a wrapper around java.util.logging.Logger and implements Logger interface
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerUtils;
import java.util.logging.Level;
/**
* Delegates to jdk logger. Maps fatal to Level.SEVERE along with error.
*/
public class JdkLogger implements Logger {
private java.util.logging.Logger log;
public JdkLogger(java.util.logging.Logger log) {
this.log = log;
}
public void error(String msg, String... args) {
log.log(Level.SEVERE, LoggerUtils.format(msg, args));
}
public void error(String msg, Throwable ex, String... args) {
log.log(Level.SEVERE, LoggerUtils.format(msg, args), ex);
}
...
}
Check the source code to see more details.
Defining which factory to use
Now you must tell XWork/Struts2 to use your implementation, just define system property like below:
-Dxwork.loggerFactory=com.demo.MyLoggerFactory
you can use the same to explicit tell the framework which implementation to use and don’t depend on class discovery, eg.:
-Dxwork.loggerFactory=com.opensymphony.xwork2.util.logging.slf4j.Slf4jLoggerFactory
or
-Dxwork.loggerFactory=com.opensymphony.xwork2.util.logging.log4j2.Log4j2LoggerFactory
will enable Slf4j or Log4j2 even if there is commons-logging on classpath available (commons-logging is the first LoggerFactory to look for).