Question
How can I configure Java Util Logging to direct logs to two different files?
# Example logging.properties configuration for dual file logging
handlers=java.util.logging.FileHandler, java.util.logging.FileHandler
# Configure first file handler
java.util.logging.FileHandler.pattern = myapp-log1.%u.%g.txt
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 2
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
# Configure second file handler
java.util.logging.FileHandler.pattern = myapp-log2.%u.%g.txt
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 2
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
Answer
Configuring Java Util Logging (JUL) to log messages to two different files is manageable through a custom setup of the logging configuration file, typically named 'logging.properties'. This setup allows you to define multiple handlers, each directing output to a different log file. Below, I provide a detailed guide on how to achieve this.
# Example logging.properties configuration for dual file logging
handlers=java.util.logging.FileHandler, java.util.logging.FileHandler
# Configure first FileHandler
java.util.logging.FileHandler.pattern = logs/myapp-log1.%u.%g.txt
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 2
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
# Configure second FileHandler
java.util.logging.FileHandler.pattern = logs/myapp-log2.%u.%g.txt
java.util.logging.FileHandler.limit = 50000
java.util.logging.FileHandler.count = 2
java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter
Causes
- Java Util Logging configurations might not include multiple handlers by default.
- Improper configuration of file paths or handlers could lead to logs not being generated.
Solutions
- Edit the `logging.properties` file to include configurations for multiple `FileHandler`s.
- Ensure the log file paths are correctly specified and accessible.
Common Mistakes
Mistake: Not specifying the correct file paths for the log handlers.
Solution: Ensure the file paths in the logging configuration are correct and that the application has the necessary permissions to write to those paths.
Mistake: Omitting the proper configuration for each handler in logging.properties.
Solution: Each handler must be defined separately; ensure all properties are correctly configured for both handlers.
Helpers
- Java Util Logging
- log to multiple files
- logging.properties configuration
- Java logging tutorial
- Java file logging setup
