The basic principles and workflows of the "Utilities Logging" framework in the Java class library

The "Utilities Logging" framework in the Java library is a tool to track and record events and errors in the system.It provides a simple and powerful method to record the behavior of the application and generate a log.This article will introduce the basic principles and workflows of the Utilities Logging framework, and provide some Java code examples to illustrate its usage. ## Overview The Utilities Logging framework is a tool commonly used in Java development. It provides the operating status of the application and the function of generating logs.By using this framework, developers can easily record logs to different targets (such as console, files, databases, etc.), and specify the level of logs (such as debugging, information, warning, errors, etc.) according to need.This enables developers to better understand the behavior of applications and timely capture and solve problems. ## Fundamental The basic principle of the Utilities Logging framework is to record the event using a log recorder (Logger).Each recorder is associated with a specific class, and the full name of this class is usually used as the name of the recorder.The purpose of using a recorder is to send log information to different processors (handler), which are responsible for output log information to different targets.For example, the console processor outputs log information to the console, and the file processor writes the log information into the file, and the database processor writes the log information into the database. ## Workingflow The workflow of the Utilities Logging framework is as follows: 1. Create a recorder: Create a recorder by `Logger.getLogger (String name) '.The name of the recorder is usually the full name of the relevant class. import java.util.logging.Logger; Logger logger = Logger.getLogger("com.example.myapp"); 2. Configure the processor: Configure the processor by `Logger.addhandler (handler handler) '.You can add multiple processors to output log information to different goals. import java.util.logging.ConsoleHandler; import java.util.logging.FileHandler; import java.util.logging.Handler; Handler consoleHandler = new ConsoleHandler(); Handler fileHandler = new FileHandler("logs/myapp.log"); logger.addHandler(consoleHandler); logger.addHandler(fileHandler); 3. Set the log level: Set the log level by setting the method of `Logger.SetLevel (Level Level).You can set different levels to control the output of log information. import java.util.logging.Level; logger.setLevel(Level.INFO); 4. Record log: Use the recorder's `LOVEL Level, String Message) method to record the log.You can choose different log levels and message content as needed. logger.log(Level.INFO, "This is an info message"); logger.log(Level.WARNING, "This is a warning message"); 5. Close the processor: When the application is terminated, the processor needs to be turned off to ensure that all the log information is output correctly. for (Handler handler : logger.getHandlers()) { handler.close(); } ## sample code Below is a simple Java code example, demonstrating the basic usage of the Utilities Logging framework: import java.util.logging.ConsoleHandler; import java.util.logging.FileHandler; import java.util.logging.Handler; import java.util.logging.Level; import java.util.logging.Logger; public class LoggingExample { private static final Logger logger = Logger.getLogger(LoggingExample.class.getName()); public static void main(String[] args) throws Exception { Handler consoleHandler = new ConsoleHandler(); Handler fileHandler = new FileHandler("logs/myapp.log"); logger.addHandler(consoleHandler); logger.addHandler(fileHandler); logger.setLevel(Level.INFO); logger.log(Level.INFO, "This is an info message"); logger.log(Level.WARNING, "This is a warning message"); for (Handler handler : logger.getHandlers()) { handler.close(); } } } The above code creates a recorder `Logger`, output the log information into the console and file, and set the log level to INFO.Then, use the `logger.log ()` method to record an INFO -level log information and a warning level log information.Finally, turn off all processors to ensure that log information is output correctly. ## Summarize The Utilities Logging framework is a practical tool in the Java class library to record the operating status and generating logs of the application.This article introduces the basic principles and workflows of the framework, and provides a simple Java code example to illustrate its usage.By using the Utilities Logging framework, developers can better understand and control applications' behaviors and timely capture and solve problems.