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

Question

I have a situation in which I want to write all logs created by me into a text file   We are using java util logging Logger API to generate the logs   I tried   private static Logger logger   Logger getLogger className class getName     FileHandler fh     fh   new FileHandler  C  className log       logger addHandler fh      But still getting my logs on console only

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Here is my logging class based on the accepted answer   import java io File  import java io IOException  import java nio file Files  import java nio file Paths  import java text DateFormat  import java text SimpleDateFormat  import java util Date  import java util logging     public class ErrorLogger       private Logger logger       public ErrorLogger                 logger   Logger getAnonymousLogger             configure               private void configure                 try                       String logsDirectoryFolder    logs               Files createDirectories Paths get logsDirectoryFolder                FileHandler fileHandler   new FileHandler logsDirectoryFolder   File separator   getCurrentTimeString       log                logger addHandler fileHandler               SimpleFormatter formatter   new SimpleFormatter                fileHandler setFormatter formatter             catch  IOException exception                        exception printStackTrace                       addCloseHandlersShutdownHook               private void addCloseHandlersShutdownHook                 Runtime getRuntime   addShutdownHook new Thread    - gt                           Close all handlers to get rid of empty  LCK files             for  Handler handler   logger getHandlers                                  handler close                                          private String getCurrentTimeString                 DateFormat dateFormat   new SimpleDateFormat  yyyy-MM-dd-HH-mm-ss            return dateFormat format new Date                public void log Exception exception                logger log Level SEVERE      exception

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A good library available named log4j for Java  This will provide numerous feature  Go through link and you will find your solution

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import java io IOException  import org apache log4j Appender  import org apache log4j FileAppender  import org apache log4j Logger  import org apache log4j SimpleLayout           author Kiran         public class MyLogger        public MyLogger                public static void main String   args            Logger logger   Logger getLogger  MyLog            Appender fh   null          try               fh   new FileAppender new SimpleLayout     MyLogFile log                logger addAppender fh               fh setLayout new SimpleLayout                 logger info  My first log              catch  SecurityException e                e printStackTrace              catch  IOException e                e printStackTrace                      logger info  Hi How r u

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Here is an example of how to overwrite Logger configuration from the code  Does not require external configuration file     FileLoggerTest java   import java io ByteArrayInputStream  import java io IOException  import java util logging Level  import java util logging LogManager  import java util logging Logger   public class FileLoggerTest        public static void main String   args             try               String h   MyLogHandler class getCanonicalName                StringBuilder sb   new StringBuilder                sb append   level ALL n                sb append  handlers    append h  append   n                LogManager getLogManager   readConfiguration new ByteArrayInputStream sb toString   getBytes  UTF-8                catch  IOException   SecurityException ex                   Do something about it                    Logger getGlobal   severe  Global SEVERE log entry            Logger getLogger FileLoggerTest class getName    log Level SEVERE   This is a SEVERE log entry            Logger getLogger  SomeName   log Level WARNING   This is a WARNING log entry            Logger getLogger  AnotherName   log Level INFO   This is an INFO log entry            Logger getLogger  SameName   log Level CONFIG   This is an CONFIG log entry            Logger getLogger  SameName   log Level FINE   This is an FINE log entry            Logger getLogger  SameName   log Level FINEST   This is an FINEST log entry            Logger getLogger  SameName   log Level FINER   This is an FINER log entry            Logger getLogger  SameName   log Level ALL   This is an ALL log entry               MyLogHandler java  import java io IOException  import java util logging FileHandler  import java util logging Level  import java util logging LogRecord  import java util logging SimpleFormatter   public final class MyLogHandler extends FileHandler        public MyLogHandler   throws IOException  SecurityException           super   tmp path-to-log log            setFormatter new SimpleFormatter             setLevel Level ALL               Override     public void publish LogRecord record            System out println  Some additional logic            super publish record

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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

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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  lt home directory gt  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

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Maybe this is what you need      import java awt event ActionEvent  import java awt event ActionListener  import java io IOException  import java util logging FileHandler  import java util logging Level  import java util logging Logger  import javax swing JButton  import javax swing JFrame  import javax swing JOptionPane  import javax swing JPanel          LogToFile class    This class is intended to be use with the default logging class of java    It save the log in an XML file  and display a friendly message to the user     author Ibrabel  lt ibrabel gmail com gt      public class LogToFile        protected static final Logger logger Logger getLogger  MYLOG                   log Method         enable to log all exceptions to a file and display user message on demand         param ex         param level         param msg              public static void log Exception ex  String level  String msg            FileHandler fh   null          try               fh   new FileHandler  log xml  true               logger addHandler fh               switch  level                    case  severe                       logger log Level SEVERE  msg  ex                       if  msg equals                              JOptionPane showMessageDialog null msg                               Error   JOptionPane ERROR MESSAGE                       break                  case  warning                       logger log Level WARNING  msg  ex                       if  msg equals                              JOptionPane showMessageDialog null msg                               Warning   JOptionPane WARNING MESSAGE                       break                  case  info                       logger log Level INFO  msg  ex                       if  msg equals                              JOptionPane showMessageDialog null msg                               Info   JOptionPane INFORMATION MESSAGE                       break                  case  config                       logger log Level CONFIG  msg  ex                       break                  case  fine                       logger log Level FINE  msg  ex                       break                  case  finer                       logger log Level FINER  msg  ex                       break                  case  finest                       logger log Level FINEST  msg  ex                       break                  default                      logger log Level CONFIG  msg  ex                       break                          catch  IOException   SecurityException ex1                logger log Level SEVERE  null  ex1             finally              if fh  null fh close                         public static void main String   args                            Create simple frame for the example                    JFrame myFrame   new JFrame            myFrame setTitle  LogToFileExample            myFrame setSize 300  100           myFrame setDefaultCloseOperation JFrame EXIT ON CLOSE           myFrame setLocationRelativeTo null           JPanel pan   new JPanel            JButton severe   new JButton  severe            pan add severe           JButton warning   new JButton  warning            pan add warning           JButton info   new JButton  info            pan add info                           Create an exception on click to use the LogToFile class                    severe addActionListener new ActionListener                  Override             public void actionPerformed ActionEvent ae                    int j   20  i   0                  try                       System out println j i                     catch  ArithmeticException ex                        log ex  severe   You can t divide anything by zero                                                           warning addActionListener new ActionListener                  Override             public void actionPerformed ActionEvent ae                    int j   20  i   0                  try                       System out println j i                     catch  ArithmeticException ex                        log ex  warning   You can t divide anything by zero                                                           info addActionListener new ActionListener                  Override             public void actionPerformed ActionEvent ae                    int j   20  i   0                  try                       System out println j i                     catch  ArithmeticException ex                        log ex  info   You can t divide anything by zero                                                                          Add the JPanel to the JFrame and set the JFrame visible                    myFrame setContentPane pan           myFrame setVisible true

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int SIZE     lt intialize-here gt   int ROTATIONCOUNT     lt intialize-here gt    Handler handler   new FileHandler  test log   SIZE  LOG ROTATIONCOUNT   logger addHandler handler          for your code        you can also set logging levels Logger getLogger this getClass   getName    log Level        addHandler handler

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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

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Hope people find this helpful  public static void writeLog String info        String filename    activity log       String FILENAME    C   testing      filename      BufferedWriter bw   null      FileWriter fw   null      try           fw   new FileWriter FILENAME  true           bw   new BufferedWriter fw           bw write info           bw write   n          catch  IOException e            e printStackTrace          finally           try               if  bw    null                  bw close                if  fw    null                  fw close              catch  IOException ex                ex printStackTrace

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

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