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This article mainly shows you the "sample analysis of the Spring Boot log framework", which is easy to understand and well-organized. I hope it can help you solve your doubts. Let the editor lead you to study and study the "sample analysis of the Spring Boot log framework".

In Java applications, logs are generally divided into the following five levels:

ERROR error message

WARN warning message

INFO General Information

DEBUG debugging information

TRACE tracking information

Spring Boot uses Apache's Commons Logging as the internal logging framework, which is only a logging interface, which needs to be specified for the corresponding logging implementation in practical applications.

The default logging implementation of SpringBt is Java Util Logging, which is the log package that comes with JDK. Of course, SpringBt also supports popular logging implementations such as Log4J and Logback.

The above logging implementations are collectively referred to as the logging framework.

Let's put it into practice!

Use the Spring Boot Logging plug-in

First, add the configuration to the application.properties file:

Logging.level.root=INFO

The code of the controller is as follows:

Package com.hansonwang99.controller;import com.hansonwang99.K8sresctrlApplication;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestController@RequestMapping ("/ testlogging") public class LoggingTestController {private static Logger logger = LoggerFactory.getLogger (K8sresctrlApplication.class); @ GetMapping ("/ hello") public String hello () {logger.info ("test logging..."); return "hello" }}

Running result

Because the log level is set to INFO, log information containing INFO and above will be printed.

As you can see here, most of the INFO logs come from the SpringBt framework itself. If we want to block them, we can set the log level to ERROR first, so that the INFO information of the framework itself will not be printed. Then set the specific package in the application to the DEBUG-level log so that you can see only the DEBUG and above level logs in the package you are interested in.

Controls the log level of a specific package

Modification of configuration in application.yml

Logging: level: root: error com.hansonwang99.controller: debug

Obviously, set the root log level to ERROR, and then set the log level of the com.hansonwang99.controller package to DEBUG, that is, disable all and then allow individual setting methods

Controller code

Package com.hansonwang99.controller;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestController@RequestMapping ("/ testlogging") public class LoggingTestController {private Logger logger = LoggerFactory.getLogger (this.getClass ()); @ GetMapping ("/ hello") public String hello () {logger.info ("test logging..."); return "hello";}}

Running result

It can be seen that the INFO level logs of the framework itself are all hidden, while the logs in the specified package are printed smoothly by level.

Output the log to a file

Logging: level: root: error com.hansonwang99.controller: debug file: ${user.home} / logs/hello.log

Running result

Using Spring Boot Logging, we found that although the log has been output to a file, a copy is still printed in the console, and it is found that using org.slf4j.Logger can not solve this problem.

Integrated Log4J logging framework

Add dependencies to pom.xml

Org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-logging Org.springframework.boot spring-boot-starter-log4j2

Add the log4j2.xml file in the resources directory as follows:

The other code remains the same.

The running program found that there was no log output in the console, but there was something in the hello2.log file, which was in line with our expectations:

And the log format matches that defined in the pattern= "% d {HH:mm:ss,SSS}% p% c (% L) -% m% n" format.

Further practice of Log4J

Pom.xml configuration:

Org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-logging Org.springframework.boot spring-boot-starter-log4j2

Log4j2.xml configuration

Springboot-web logs/$ {app_name}

Controller code:

Package com.hansonwang99.controller;import org.apache.logging.log4j.LogManager;import org.apache.logging.log4j.Logger;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;@RestController@RequestMapping ("/ testlogging") public class LoggingTestController {private final Logger logger = LogManager.getLogger (this.getClass ()); @ GetMapping ("/ hello") public String hello () {for (int item0)

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