In log4j2, you
would create a plugin for create custom appender in log4j2.
When you
annotate your custom Appender class with @Plugin(name=”MyCustomAppender”,
category=”core” elementType=”appender” ,printObject=true) the plugin name becomes the configuration element name, so a
configuration with your custom appender would then look like this:
Log4j2.xml
<?xml version="1.0"
encoding="UTF-8"?>
<Configuration status="warn"
packages="com.madhu.appender">
<Appenders>
<MyCustomAppender name="myapp"
>
<PatternLayout pattern="serial no: %sn
| Date: %d | level:%level | class name:%logger | method
name:%M() | line number:%L | Location: %l | message:%m%n" />
</MyCustomAppender>
</Appenders>
<Loggers>
<Root level="all"
additivity="false">
<AppenderRef ref="myapp"
/>
</Root>
</Loggers>
</Configuration>
In log4j2.xml file don’t forgot packages
attribute here configure your custom appender package.
Now we are
create plugin for appender.
MyCustomImpl.java
@Plugin(name="MyCustomAppender", category="Core", elementType="appender", printObject=true)
public class MyCustomImpl extends AbstractAppender {
private final ReadWriteLock rwLock = new
ReentrantReadWriteLock();
private final Lock readLock = rwLock.readLock();
protected MyCustomImpl(String name, Filter filter,
Layout<? extends Serializable> layout, final boolean ignoreExceptions) {
super(name, filter, layout, ignoreExceptions);
}
@PluginFactory
public static MyCustomImpl
createAppender(
@PluginAttribute("name") String name,
@PluginElement("Layout") Layout<? extends Serializable> layout,
@PluginElement("Filter") final Filter filter,
@PluginAttribute("otherAttribute") String otherAttribute) {
if (name == null) {
LOGGER.error("No name provided
for MyCustomAppenderImp");
return null;
}
if (layout == null) {
layout = PatternLayout.createDefaultLayout();
}
return new MyCustomImpl(name, filter, layout, true);
}
@Override
public void append(LogEvent event) {
readLock.lock();
try {
final byte[] bytes = getLayout().toByteArray(event);
// here I am printing logs into
console
System.out.println("LOG: " +new String(bytes, "UTF-8"));
} catch (Exception ex) {
if (!ignoreExceptions()) {
throw new
AppenderLoggingException(ex);
}
} finally {
readLock.unlock();
}
}
}
Now we can test our custom appender. For
this we can write one test class.
Note:
Here custom appender plugin name and configuration appender name is same otherwise
its won’t work.
Test.java
public class Test {
public static final Logger LOGGER=LogManager.getLogger(Test.class);
public static void main(String[] args) throws IOException {
LOGGER.info("this is info
message");
LOGGER.warn("this is
warning message");
}
}
The output comes like below.
LOG: serial no: 1 | Date: 2015-06-23 15:32:56,069 | level:INFO | class name:com.madhu.appender.Test
| method name:main() | line number:15
| Location: com.madhu.appender.Test.main(Test.java:15) | message:this is
info message
LOG: serial no: 2 | Date: 2015-06-23 15:32:56,072 | level:WARN | class name:com.madhu.appender.Test
| method name:main() | line number:16
| Location: com.madhu.appender.Test.main(Test.java:16) | message:this is
warning message
