how can we remove extra message in log files

i have a simple logging program ie:

public class LoggingExample1 {
 public static void main(String args[]) {
try {
  LogManager lm = LogManager.getLogManager();
  Logger logger;
  FileHandler fh = new FileHandler("log_test.txt");

  logger = Logger.getLogger("LoggingExample1");
  lm.addLogger(logger);
  logger.setLevel(Level.INFO);

  fh.setFormatter(new SimpleFormatter());

  logger.addHandler(fh);
  // root logger defaults to SimpleFormatter. We don't want messages
  // logged twice.
  //logger.setUseParentHandlers(false);

  logger.log(Level.INFO, "test 1");
  logger.log(Level.INFO, "test 2");
  logger.log(Level.INFO, "test 3");
  fh.close();
} catch (Exception e) {
  System.out.println("Ex开发者_如何学Pythonception thrown: " + e);
  e.printStackTrace();
}
}
}

i get this log:

Aug 1, 2011 5:36:37 PM LoggingExample1 main
INFO: test 1
Aug 1, 2011 5:36:37 PM LoggingExample1 main
INFO: test 2
Aug 1, 2011 5:36:37 PM LoggingExample1 main
INFO: test 3

but i want to remove the messages like: LoggingExample1 main and INFO and only keep the data that are logged by code. what can i do???

This is because you are using a SimpleFormatter which always logs the class name, method name etc. If you don't want this information, you can write your own formatter. Here is a simple example of a formatter which just outputs the log level and the log message:

import java.util.logging.*;

class MyFormatter extends Formatter{

    /* (non-Javadoc)
     * @see java.util.logging.Formatter#format(java.util.logging.LogRecord)
     */
    @Override
    public String format(LogRecord record) {
        StringBuilder sb = new StringBuilder();
        sb.append(record.getLevel()).append(':');
        sb.append(record.getMessage()).append('\n');
        return sb.toString();
    }    
}

Use this formatter in your file handler:

fh.setFormatter(new MyFormatter());

This will output:

INFO:test 1
INFO:test 2
INFO:test 3

Extend your class with formatter class as below:

public class MyFormatter extends SimpleFormatter{

@Override

public synchronized String format(LogRecord record){

    record.setSourceClassName(MyFormatter.class .getName());
    return String.format(
            " [%1$s] :%2$s\n",
            record.getLevel().getName(), formatMessage(record));

    }
}

Then in you main class, set console handler and filehandler format as your class format object. In my case ,it is consoleHandler.format(new MyFormatter); filehandler.format(new Myformatter);

Most imp thing is you have to set logger.setUseParentHandler(false);

now you are good to go!

If I understand you correctly, you want to remove INFO and only have test 1 and so on?

If that is the case, I don't think its possible. The reason is that you need to know what type of message this is.

ERROR
WARNING
INFO
DEBUG
TRACE

You can change the level to only display WARNING and up if you want.

Here is how I do this, simplified version of SimpleFormatter

package org.nibor.git_merge_repos;

import java.util.Date;
import java.util.logging.Formatter;
import java.util.logging.LogRecord;


public class CustomLogFormatter extends Formatter {

    private final Date dat = new Date();

    private static final String seperator = " : ";

    public synchronized String format(LogRecord record) {
        dat.setTime(record.getMillis());
        return dat + seperator + record.getLevel().getName() + seperator + record.getMessage() + "\n";

    }
}