配置log4j.properties以将错误输出到文件

Question

我有多个java类，并希望将调试和错误输出写入不同的日志文件以及不同的位置。如何使用log4j.properties实现这一目标？

Answer 1

您需要过滤消息。但是，过滤器仅可通过XML配置文件log4j.xml获得。

• org.apache.log4j.varia.LevelRangeFilter

  如果要指定appender的较低范围和较高范围：

  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE log4j:configuration PUBLIC "-//log4j/log4j Configuration//EN"
                                       "log4j.dtd">
  <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
  
      <!-- DEBUG appender -->
      <appender name="DEBUGFILE" class="org.apache.log4j.FileAppender">
          <param name="file" value="debug.log" />
          <layout class="org.apache.log4j.SimpleLayout" />
          <filter class="org.apache.log4j.varia.LevelRangeFilter">
              <param name="LevelMin" value="DEBUG" />
              <param name="LevelMax" value="DEBUG" />
          </filter>
      </appender>
  
      <!-- ERROR appender -->
      <appender name="ERRORFILE" class="org.apache.log4j.FileAppender">
          <param name="file" value="error.log" />
          <layout class="org.apache.log4j.SimpleLayout" />
          <filter class="org.apache.log4j.varia.LevelRangeFilter">
              <param name="LevelMin" value="ERROR" />
              <param name="LevelMax" value="ERROR" />
          </filter>
      </appender>
  
      <!-- root -->
      <root>
          <priority value="ALL" />
          <appender-ref ref="DEBUGFILE" />
          <appender-ref ref="ERRORFILE" />
      </root>
  
  </log4j:configuration>
  

• org.apache.log4j.varia.LevelMatchFilter

  如果您想过滤单个级别：

  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE log4j:configuration PUBLIC "-//log4j/log4j Configuration//EN"
                                       "log4j.dtd">
  <log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
  
      <!-- DEBUG appender -->
      <appender name="DEBUGFILE" class="org.apache.log4j.FileAppender">
          <param name="file" value="debug.log" />
          <layout class="org.apache.log4j.SimpleLayout" />
          <filter class="org.apache.log4j.varia.LevelMatchFilter">
              <param name="levelToMatch" value="DEBUG" />
          </filter>
      </appender>
  
      <!-- ERROR appender -->
      <appender name="ERRORFILE" class="org.apache.log4j.FileAppender">
          <param name="file" value="error.log" />
          <layout class="org.apache.log4j.SimpleLayout" />
          <filter class="org.apache.log4j.varia.LevelMatchFilter">
              <param name="levelToMatch" value="ERROR" />
          </filter>
      </appender>
  
      <!-- root -->
      <root>
          <priority value="ALL" />
          <appender-ref ref="DEBUGFILE" />
          <appender-ref ref="ERRORFILE" />
      </root>
  
  </log4j:configuration>