Use Apache Log4J framework for abnormal processing and error log records
Use Apache Log4J framework for abnormal processing and error log records
Overview:
In software development, abnormal processing is very important for ensuring the stability and reliability of the system.Apache Log4j is a powerful logging tool that helps us capture and record abnormalities and error messages during the application of the application.This article will introduce how to use the Apache Log4j framework for abnormal processing and error log records, and provide the corresponding example code and configuration.
Log4j configuration file:
First of all, we need to create a log4j.properties configuration file for the format and output target of specifying log records.The following is a basic configuration example:
properties
# Set the root log level
log4j.rootLogger=INFO, Console, File
# Console output configuration
log4j.appender.Console=org.apache.log4j.ConsoleAppender
log4j.appender.Console.layout=org.apache.log4j.PatternLayout
log4j.appender.Console.layout.ConversionPattern=[%p] %d %c %M - %m%n
# File output configuration
log4j.appender.File=org.apache.log4j.RollingFileAppender
log4j.appender.File.File=logs/application.log
log4j.appender.File.MaxFileSize=5MB
log4j.appender.File.MaxBackupIndex=10
log4j.appender.File.layout=org.apache.log4j.PatternLayout
log4j.appender.File.layout.ConversionPattern=[%p] %d %c %M - %m%n
In the configuration file above, we have two output targets: console and file.Console is used to output logs to the console, and file is used to output logs to the specified file.Appropriate adjustments can be made as needed.
Code example:
Below is a Java code example using LOG4J record abnormalities and error logs:
import org.apache.log4j.Logger;
public class ExampleClass {
private static final Logger logger = Logger.getLogger(ExampleClass.class);
public static void main(String[] args) {
try {
// code logic
} catch (Exception e) {
Logger.error ("" Occasion: " + E.getMessage (), E);
}
int result = divide(10, 0);
}
private static int divide(int dividend, int divisor) {
try {
return dividend / divisor;
} catch (ArithmeticException e) {
logger.error ("" removal abnormal: " + e.getMessage (), e);
return 0;
}
}
}
In the above example, first of all, we obtain a logger instance through the `logger.getLogger` method, and the parameter is the class object of the current class.Then, in the code, we can record different levels of log information by calling different methods of Logger.
In the TRY-CATCH block, the abnormal information is recorded by calling the `logger.error` method.In addition, we can use other methods such as `Logger.fatal`, Logger.warn`,` Logger.info` and other records of the corresponding level of log information.
Log4j log level:
LOG4J provides different logs. You can choose the appropriate level to record log information according to needs.The following is the log level of log4j and the corresponding record method:
-` Logger.Fatal` - fatal error
-` Logger.error` - Error
-` Logger.warn` - Warning
-` logger.info` - Information
-` logger.debug` - debug
-` logger.trace` - tracking
According to actual needs, select the appropriate method to record the corresponding level of information.
Summarize:
This article introduces how to use the Apache Log4j framework for abnormal processing and error log records.By configured log4j.properties files, we can specify the output format and output target of the log.Then, record different levels of log information by calling different methods of Logger in the code.Reasonable use of log4j can help us accurately locate and investigate abnormalities and errors in applications, and improve the stability and reliability of the system.
