JavaEE项目中的Log4j2配置文件

Question

我有简单的 Maven Java-EE 基于 Jersey Web 服务在我的 Eclipse 中运行 Windows 10. 项目是从创建的jersey-quickstart-webapp神器。我正在尝试使用 Log4j 记录器，但找不到放置 log4j2.xml 文件的位置。我试图将它与源代码 java 文件放在一起，但记录器抱怨找不到配置文件。保存配置文件的正确位置是什么？

Answer 1

根据docs，Log4j2会按照以下顺序查找配置文件：

1. Log4j will inspect the "log4j.configurationFile" system property and, if set, will attempt to load the configuration using the ConfigurationFactory that matches the file extension.
2. If no system property is set the properties ConfigurationFactory will look for log4j2-test.properties in the classpath.
3. If no such file is found the YAML ConfigurationFactory will look for log4j2-test.yaml or log4j2-test.yml in the classpath.
4. If no such file is found the JSON ConfigurationFactory will look for log4j2-test.json or log4j2-test.jsn in the classpath.
5. If no such file is found the XML ConfigurationFactory will look for log4j2-test.xml in the classpath.
6. If a test file cannot be located the properties ConfigurationFactory will look for log4j2.properties on the classpath.
7. If a properties file cannot be located the YAML ConfigurationFactory will look for log4j2.yaml or log4j2.yml on the classpath.
8. If a YAML file cannot be located the JSON ConfigurationFactory will look for log4j2.json or log4j2.jsn on the classpath.
9. If a JSON file cannot be located the XML ConfigurationFactory will try to locate log4j2.xml on the classpath.
10. If no configuration file could be located the DefaultConfiguration will be used. This will cause logging output to go to the console.

所以你可以看到除了(1)之外，都是从类路径中查找配置文件。在标准的 Maven 项目中，/src/main/resources 是类路径的根。所以你可以把 log4j2.xml 放在 /src/main/resources.

否则，你必须通过log4j.configurationFile系统显式指定配置文件属性 :

-Dlog4j.configurationFile=path/to/log4j2.xml

Answer 2

放入资源目录。通常，所有配置文件都保存在那里。