How to write logs in text file when using java.util.logging.Logger

Solution 1:

Try this sample. It works for me.

public static void main(String[] args) {  

    Logger logger = Logger.getLogger("MyLog");  
    FileHandler fh;  

    try {  

        // This block configure the logger with handler and formatter  
        fh = new FileHandler("C:/temp/test/MyLogFile.log");  
        logger.addHandler(fh);
        SimpleFormatter formatter = new SimpleFormatter();  
        fh.setFormatter(formatter);  

        // the following statement is used to log any messages  
        logger.info("My first log");  

    } catch (SecurityException e) {  
        e.printStackTrace();  
    } catch (IOException e) {  
        e.printStackTrace();  
    }  

    logger.info("Hi How r u?");  

}

Produces the output at MyLogFile.log

Apr 2, 2013 9:57:08 AM testing.MyLogger main  
INFO: My first log  
Apr 2, 2013 9:57:08 AM testing.MyLogger main  
INFO: Hi How r u?

Edit:

To remove the console handler, use

logger.setUseParentHandlers(false);

since the ConsoleHandler is registered with the parent logger from which all the loggers derive.

Solution 2:

Firstly, where did you define your logger and from what class\method trying to call it? There is a working example, fresh baked:

public class LoggingTester {
    private final Logger logger = Logger.getLogger(LoggingTester.class
            .getName());
    private FileHandler fh = null;

    public LoggingTester() {
        //just to make our log file nicer :)
        SimpleDateFormat format = new SimpleDateFormat("M-d_HHmmss");
        try {
            fh = new FileHandler("C:/temp/test/MyLogFile_"
                + format.format(Calendar.getInstance().getTime()) + ".log");
        } catch (Exception e) {
            e.printStackTrace();
        }

        fh.setFormatter(new SimpleFormatter());
        logger.addHandler(fh);
    }

    public void doLogging() {
        logger.info("info msg");
        logger.severe("error message");
        logger.fine("fine message"); //won't show because to high level of logging
    }
}   

In your code you forgot to define the formatter, if you need simple one you can do it as I mentioned above, but there is another option, you can format it by yourself, there is an example (just insert it instead of this line fh.setFormatter(new SimpleFormatter()) following code):

fh.setFormatter(new Formatter() {
            @Override
            public String format(LogRecord record) {
                SimpleDateFormat logTime = new SimpleDateFormat("MM-dd-yyyy HH:mm:ss");
                Calendar cal = new GregorianCalendar();
                cal.setTimeInMillis(record.getMillis());
                return record.getLevel()
                        + logTime.format(cal.getTime())
                        + " || "
                        + record.getSourceClassName().substring(
                                record.getSourceClassName().lastIndexOf(".")+1,
                                record.getSourceClassName().length())
                        + "."
                        + record.getSourceMethodName()
                        + "() : "
                        + record.getMessage() + "\n";
            }
        });

Or any other modification whatever you like. Hope it helps.

Solution 3:

Location of log file can be control through logging.properties file. And it can be passed as JVM parameter ex : java -Djava.util.logging.config.file=/scratch/user/config/logging.properties

Details: https://docs.oracle.com/cd/E23549_01/doc.1111/e14568/handler.htm

Configuring the File handler

To send logs to a file, add FileHandler to the handlers property in the logging.properties file. This will enable file logging globally.

handlers= java.util.logging.FileHandler Configure the handler by setting the following properties:

java.util.logging.FileHandler.pattern=<home directory>/logs/oaam.log
java.util.logging.FileHandler.limit=50000
java.util.logging.FileHandler.count=1
java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter

java.util.logging.FileHandler.pattern specifies the location and pattern of the output file. The default setting is your home directory.

java.util.logging.FileHandler.limit specifies, in bytes, the maximum amount that the logger writes to any one file.

java.util.logging.FileHandler.count specifies how many output files to cycle through.

java.util.logging.FileHandler.formatter specifies the java.util.logging formatter class that the file handler class uses to format the log messages. SimpleFormatter writes brief "human-readable" summaries of log records.

To instruct java to use this configuration file instead of $JDK_HOME/jre/lib/logging.properties:

java -Djava.util.logging.config.file=/scratch/user/config/logging.properties