Application and Technical Analysis of Apache Log4J Web Framework in Java Class Libraies
Apache Log4j is a classic log record framework for Java applications.This article will explore the application and related technical analysis of the Apache Log4J Web framework in the Java library.If necessary, we will explain the complete programming code and related configuration.
Apache Log4j is a powerful and widely used log record tool that helps developers to achieve flexible logging functions in the application.It provides a variety of log levels (such as DEBUG, Info, Warn, ERROR, and FATAL), which can be enabled or disabled logging of specific levels as needed.In addition, LOG4J also supports a variety of output methods of log records, such as output logs to consoles, files, databases, etc.
Use the log4j web framework in the Java library, we need to complete the following steps:
Step 1: Introduce log4j dependencies
First, add the dependencies to LOG4J in the POM.XML or Build.gradle file in the Java project.For example, in the Maven project, the following code can be added in the DEPENDENDCIES part of the POM.XML file:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.17.1</version>
</dependency>
Step 2: Create log4j configuration file
Create a log4j2.xml or log4j2.properties file in the resource directory of the project to configure the LOG4J behavior.Below is a sample of the content of the configuration file of the 1st LOG4J2.xml:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="Console"/>
</Root>
</Loggers>
</Configuration>
This configuration file outputs the log to the console, the format is timestamp, thread name, log level, recorder name and message.
Step 3: Use LOG4J in the Java library
In the Java class library, we can use log4j through the following code:
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class MyClass {
private static final Logger logger = LogManager.getLogger(MyClass.class);
public void doSomething() {
Logger.info ("This is an info -level log message");
try {
// Execute certain operations
} catch (Exception e) {
logger.error ("Error", e);
}
}
}
In the above examples, we first introduce Logmanager and Logger classes.Then, we create a static logger instance in the class that needs to record the log.In the Dosomething () method, we record different levels of log messages by calling different methods of logger.
It should be noted that the log level is configured.In the log4j configuration file, we can specify the minimum level of log records by modifying the level attribute in the `root level =" info ">` `` `` `` `` `` `` ``In this example, only the INFO level and above log messages are recorded.
Through the above steps, we can successfully use the log4j web framework in the Java class library for log records.Using the LOG4J Web framework can make our applications easier to manage and debug, help us quickly locate and solve potential problems.
