How to use the NLOG4J framework for the log record of the Java class library
NLOG4J is a powerful log record framework for the Java library.It provides a reliable log record function that can help developers quickly and accurately identify and solve problems.This article will introduce how to use the NLOG4J framework for the log records of the Java class library and provide some Java code examples.
### What is nlog4j?
NLOG4J is a logging framework of the Java library developed by Apache.It is a new improved version of LOG4J, which is more powerful in performance and function.NLOG4J supports a variety of logging levels, including tracking, debugging, information, warnings, errors and seriousness, and can also classify and screen log messages.Using NLOG4J, you can easily add the logging function in the application to better understand the execution of the code during development and operation.
### How to use NLOG4J to perform the log record of the Java library?
The following is the steps to use the nlog4j framework to perform the log records of the Java library:
Step 1: Add nlog4j dependencies
First, you need to add NLOG4J dependency items to the project construction file (eg, maven's pom.xml).Find log4j dependencies and add the following code fragment:
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.14.0</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.14.0</version>
</dependency>
Step 2: Create log4j2.xml configuration file
Create a configuration file called log4j2.xml in the resource folder of the project, and add the following:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</Console>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="Console" />
</Root>
</Loggers>
</Configuration>
The above configuration file prints the log message to the console.
Step 3: Use NLOG4J in the Java library
In the Java library that needs to record logs, you need to add the following code example:
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class MyLibraryClass {
private static final Logger logger = LogManager.getLogger(MyLibraryClass.class);
public void doSomething() {
logger.trace("This is a trace message.");
logger.debug("This is a debug message.");
logger.info("This is an info message.");
logger.warn("This is a warning message.");
logger.error("This is an error message.");
logger.fatal("This is a fatal message.");
}
}
In the above example, a Logger instance was obtained through the getlogger method of the Logmanager class.Then, you can use different log records (trace, debug, info, warn, error, and fatal) to record log messages.
### Summarize
It is very simple to use the NLOG4J framework to perform the log record of the Java library.You only need to add NLOG4J dependency items, and use the logger instance in the Java library for log records.By configured log4j2.xml files, you can customize the format and output target of the log record.In this way, you can better understand the behavior of your application in development and operation.
