A preliminary study of the Log4j2-yaml configuration pit

I haven’t been aggressive for a long time, and I want to fiddle with new things. There is a problem that cannot be solved in log4j, so I want to try log4j2; I have never written yaml before, so I want to try a new configuration by the way.

 

The author uses maven to build Demo, and adds dependencies according to the instructions on the official website Configuration with YAML

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId> jackson-data-format-yaml </artifactId>
    <version>2.8.6</version>
</dependency>

 I am excited to write the simplest main method, print the info-level log, but keep reporting:

 

ERROR StatusLogger No log4j2 configuration file found. Using default configuration: logging only errors to the console.

I can't find the configuration file of log4j2. I checked it several times. The configuration file has been compiled successfully. How can it be found?
I have searched a lot of related articles on the Internet, but I can't find any similar problems. . .

Can't get stuck here, I really want to try log4j2, Debug the source code, this Debug, I'll go, the jackson-dataformat-yaml dependency package has some dependencies that have not been introduced, com.fasterxml.jackson. databind.ObjectMapper is red in the source file...

 

As a result, the constructor in YamlConfigurationFactory cannot properly load the Class of com.fasterxml.jackson.databind.ObjectMapper...

 

private static final String[] dependencies = new String[] {
      "com.fasterxml.jackson.databind.ObjectMapper",
      "com.fasterxml.jackson.databind.JsonNode",
      "com.fasterxml.jackson.core.JsonParser",
      "com.fasterxml.jackson.dataformat.yaml.YAMLFactory"
};

private final boolean isActive;

public YamlConfigurationFactory() {
    for (final String dependency : dependencies) {
        if (!Loader.isClassAvailable(dependency)) {
            LOGGER.debug("Missing dependencies for Yaml support");
            isActive = false;
            return;
        }
    }
    isActive = true;
}

 

 The result of isActive is false, and the configuration obtained by getConfiguration() of YamlConfigurationFactory is always null

@Override
public Configuration getConfiguration(final LoggerContext loggerContext, final ConfigurationSource source) {
    if (!isActive) {
        return null;
    }
    return new YamlConfiguration(loggerContext, source);
}

 

 

Solution:

Add jackson-databind dependency package

<dependency>
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
       <version>2.8.6</version>
</dependency>