Inserting Header Text in Log file - Log4j

[Srinath Kannan]

Hi,

I have semi-colon separated values logged to a csv file using log4j. Now i wanted to write a header in first line [only once, everyday]. How this can be done?

Example
message id, file name, start time, end time, status
MSGID1000;SAMPLE.TXT;01:05:55;07:08:44;OK
MSGID1000;SAMPLE.TXT;01:05:55;07:08:44;NOK

[Joshua Smith]

Extend PatternLayout and then override the getHeader() method.

package ex.logging;

import org.apache.log4j.PatternLayout;

public class MyPatternLayout extends PatternLayout {
	
	@Override
	public String getHeader() {
		return "message id, file name, start time, end time, status"
	}

}

log4j.appender.LOG=org.apache.log4j.DailyRollingFileAppender
log4j.appender.LOG.File=log/MyApp.log
log4j.appender.LOG.DatePattern='.'yyyy-MM-dd
log4j.appender.LOG.Append=true
log4j.appender.LOG.layout=ex.logging.MyPatternLayout
log4j.appender.LOG.layout.ConversionPattern=%m%n

Josh

[Srinath Kannan]

Hi Josh,

I extended the PatternLayout class and implemented the header. It works.

One change, we have to append line.separator character at the end of the string returned by overidden getHeader() method. if we dont append it, the first line logged comes along with the header line.

@Override  
    public String getHeader() {   
        return "message id, file name, start time, end time, status" + System.getProperty("line.separator");
    }

Thankyou very much.

[anjan singh]

Hi

How can I read the header text dynamically rather than hardcoding it in the "MyPatternLayout " class itself.

The situation is somewhat like this:
I have 50 files on which i need headers. Each file will have unique header.

How can I get this done by just writing one "MyPatternLayout " class and passing it the header text as an argument. Most preferably the header text could be done from log4j.properties itself.

Any ideas would be greatly appreciated...

[anjan singh]

I figured it out.

it was very simple. Find below the code.

Just adding a setter for header does the trick.

public class HeaderLayout extends PatternLayout{
	
	private String header;

	public void setHeader(String header){
		this.header = header;
	}

	public String getHeader(){
		
		
		return this.header+System.getProperty("line.separator");
	}

}

And in log4j.properties file add header property to your layout:

log4j.logger.HOME=ALL,HOME5
log4j.appender.HOME5=org.apache.log4j.DailyRollingFileAppender
log4j.appender.HOME5.File=C:\\HOME5Log.log
log4j.appender.HOME5.DatePattern=_yyyy-MM-dd-HH
log4j.appender.HOME5.layout=log4jTut.HeaderLayout
log4j.appender.HOME5.layout.ConversionPattern=%d %-5p %c - %m%n
log4j.appender.HOME5.layout.Header=ABC|XYZQ

[Ingoba Ningthoujam]

But When the server restart again, the header is added again. Is there a way to avoid to insert the header again until the rolling criteria is made?

[xie brandon]

Ingoba Ningthoujam wrote:But When the server restart again, the header is added again. Is there a way to avoid to insert the header again until the rolling criteria is made?

i have the same question,any methods to solve?