How to specify Custom / Extended Logger in log4j.x

问题:

I am using Custom Logger for my project eg. class MyLogger. With that i am able to log the message correctly but Its not logging the Class & Method name correctly from where log initiated.

So I think may we need to specify MyLoggger in log4j.xml but I don't know where & how ?

All suggestions are appreciated. Thanks.

---

回答1:

If you have a class MyClass:

package com.acando.norolnes;

public class MyClass {
    public String foo;
    public int bar;
}

That you want to custom format when logging, you can create a custom ObjectRenderer:

package com.acando.norolnes;

import org.apache.log4j.or.ObjectRenderer;

public class MyClassRenderer implements ObjectRenderer {

    @Override
    public String doRender(Object arg0) {
        if(arg0 instanceof MyClass) {
            MyClass m = (MyClass)arg0;
            return "("+m.foo+" "+m.bar+")";
        }
        return arg0.toString();
    }
}

And link this up in the config like this, with a -element:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd" >
<log4j:configuration>
  <renderer renderedClass="com.acando.norolnes.MyClass"
            renderingClass="com.acando.norolnes.MyClassRenderer"/>
  <appender name="stdout" class="org.apache.log4j.ConsoleAppender">
    <layout class="org.apache.log4j.PatternLayout">
      <param name="ConversionPattern" value="%d{ABSOLUTE} %5p %c{1}:%L - %m%n"/>
    </layout>
  </appender>
  <root>
    <priority value="debug"></priority>
    <appender-ref ref="stdout"/>
  </root>
</log4j:configuration>

For a more complete example, take a look at http://www.java2s.com/Code/Java/Language-Basics/log4jAcompleteexample.htm