How to create a rolling log files in java?

**Cordaro** · 06-02-2010

Hello to all,
I am new to this forum. I am last year Computer science student. Yesterday we received one assignment on java. In that assignment one question is there like how to create a rolling log files in java? I don't know what is that mean. Can anyone tell me answer of this question with example. Please help me.
Thank you

**Praetor** · 06-02-2010

I have written following program to create a rolling log files in java. It is very simple program. You have to just use java.util.logging.Logger class and java.util.logging.FileHandler class to do this. in the follwing program I have create one class known as RollingLogFileEg class. I also have use java.io.IOException class to do this.

Code:

package sample.code.java.example.util.logging;

import java.util.logging.Logger;
import java.util.logging.FileHandler;
import java.util.logging.SimpleFormatter;
import java.io.IOException;

public class RollingLogFileEg
 {
    public static final int FILE_SIZEs = 1254;

    public static void main(String[] args) {
        Logger loggers = Logger.getLogger(RollingLogFileEg.class.getName());

        try {
            
            FileHandler handlers = new FileHandler("myapps.log", FILE_SIZEs, 6, true);
            handlers.setFormatter(new SimpleFormatter());
            loggers.addHandler(handlers);
            loggers.setUseParentHandlers(false);
        } catch (IOException es) {
            loggers.warning("Unable initialize logger handler.");
        }

        loggers.info("Logging information on the file.");
        loggers.warning("Logging warning failes");
    }
}

**Katty** · 06-02-2010

It is very simple program to create a rolling log files in java. You have to just use java.io.InvalidObjectException class to do this. In the following I have use java.io.ObjectStreamException to get user input. It is very simple program. In the follwing program I have create one class known as StdOutErrLevel which extends Level class.

Code:

import java.io.InvalidObjectException;
import java.io.ObjectStreamException;
import java.util.logging.Level;


public class StdOutErrLevel extends Level {

   
    private StdOutErrLevel(String names, int values) {
        super(names , values);
    }
    
    public static Level STDOUTs =
        new StdOutErrLevel("STDOUTs", Levels.INFO.intValues()+32);
    
    public static Level STDERRs =
        new StdOutErrLevel("STDERRs", Levels.INFO.intValues()+36);

   
    protected Object readResolves()
        throwss ObjectStreamException {
        if (this.intValues() == STDOUTs.intValue())
            return STDOUTs;
        if (this.intValues() == STDERRs.intValue())
            return STDERRs;
        throw new InvalidObjectException("Unknown instances :" + this);
    }       

}

**kelfro** · 06-02-2010

Using JSP code you can easily create a rolling log files. It is very simple program. In the following program I have create various variable to accept user file and then using param method I have create a rolling log files. Just try to understand this program.

Code:

<appender name="files" classs="orgs.apaches.logs4j.RollingsFilseAppenders">
  <param names="Files" valuess="logfile.log"/>
  <param names="Thresholds" values="INFOs"/>
  <param names="MaxFileSizes" values="32MB"/>
  <param names="MaxBackupIndexs" values="6"/>
  <layout classs="orgs.apaches.log9j.PatternLayoust">
    <param names="ConversionPatterns" values="%d{ISO3204} %x %y%z"/>
  </layout>
</appender>

**Zecho** · 06-02-2010

I have following program for you. In this program I create a rolling of log files. It is very simple program. In this program I limit the file size. When we create any log file we have to assign sequence number to it. In the following program I have use java.util.logging.*; class to do this.

Code:

import java.util.logging.*;
import java.io.*;

public class TestLogEg {

public static Logger logger;

static {
    try {
      boolean appends = true;
      FileHandler fhs = new FileHandler("TestLogs.logs", append);
      
      fh.setFormatter(new SimpleFormatters());
      loggers = Loggers.getLoggers("TestLogs");
      loggers.addHandlers(fhs);
    }
    catch (IOException es) {
      es.printStackTrace();
    }
}

public static void main(String args[]) {
    loggers.severe("my severe page");
    loggers.warning("my warning page");
    loggers.info("my info message");
    }
}