Скачать или смотреть How to Configure log4j for Error-Only Logging in Spring Applications

Discover the simple steps to adjust your `log4j` configuration in Spring applications to display only error messages during testing, ensuring a cleaner console output.
---
This video is based on the question https://stackoverflow.com/q/64140663/ asked by the user 'David Àlvarez Tudela' ( https://stackoverflow.com/u/13890232/ ) and on the answer https://stackoverflow.com/a/64155665/ provided by the user 'en Lopes' ( https://stackoverflow.com/u/7661910/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: log4j config when testing to show only Errors

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Configure log4j for Error-Only Logging in Spring Applications

In modern application development, logging plays a crucial role in debugging and monitoring the behaviors of applications. However, when running tests, you might only want to see error messages to keep your console output clear and focused. If you are using log4j in a Spring application and you find that your tests produce more log messages than expected, this guide will help you configure log4j effectively to show only errors.

Understanding the Problem

You are working on a Spring application that utilizes EclipseLink and DbUnit for testing. You've set up your log4j.xml configuration file, but you still notice a plethora of log messages flooding your console, even when your intention is to display only error messages.

Here is how your current log4j.xml looks:

[[See Video to Reveal this Text or Code Snippet]]

Despite this configuration, your console is filled with log entries that include messages such as configuration details, SQL logs, and debug messages instead of limiting output to errors.

The Solution: Configuring log4j and EclipseLink

To achieve the desired effect of logging only errors during your tests, it is crucial to adjust both your logging framework (log4j) and your JPA configuration (EclipseLink). Here's a step-by-step breakdown of the necessary changes:

Step 1: Update log4j.xml Configuration

Your log4j.xml file already specifies that the root logging level is set to ERROR. This is the first step in ensuring that only error-level messages are printed. Ensure this does not have any conflicting settings and appears prominently in the configuration as you have it.

Step 2: Configure EclipseLink Logging

The next critical step involves your persistence.xml file located in src/test/java/META-INF/persistence.xml. You need to set the logging levels for EclipseLink properties correctly to prevent additional log outputs. Include the following properties within your persistence-unit definition:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Maven Configuration

Lastly, to ensure consistency across your project, you also need to double-check your pom.xml file under the properties section. Make sure that the logging levels are also set to OFF there:

[[See Video to Reveal this Text or Code Snippet]]

By implementing these changes, you should notice a significant reduction in log output during your test runs, allowing for a cleaner and more focused view of error messages on your console.

Conclusion

Configuring log4j correctly is crucial for minimizing unnecessary console output during testing in a Spring application. By setting both the log4j and EclipseLink logging levels appropriately, you can limit the console to show only error messages, thus improving your testing experience. Implement the configurations mentioned in this guide to streamline your logging setup and maintain clarity during your test executions.