Log4J2(2.5)中的java可加性
根据位于http://logging.apache.org/log4j/2.x/manual/configuration.html的Log4J2手册,使用
...
<Loggers>
<Logger name="com.foo.Bar" level="trace">
<AppenderRef ref="Console"/>
</Logger>
<Root level="error">
<AppenderRef ref="Console"/>
</Root>
</Loggers>
...
记录一份声明,比如
Logger barLogger = LogManager.getLogger(Bar.class);
barLogger.info("A simple info message");
应该产生产出
"A simple info message"
然而,我收到了两次信息,即
"A simple info message"
"A simple info message"
想知道为什么?我知道,不为条形记录器指定additivity="false"
也会将消息传播到根记录器。然而,在这种情况下,根记录器的日志级别设置为error,当我阅读手册时,不应再次记录该消息(该消息仅被记录为“info”)
有什么提示吗
更新: 我看到了@rgoers的第一个答案,这似乎是合理的。然而,在我看来,http://logging.apache.org/log4j/2.x/manual/configuration.html的文档似乎仍然过时或不正确。根据文件,该计划
public class MyApp {
// Define a static logger variable so that it references the
// Logger instance named "MyApp".
private static final Logger logger = LogManager.getLogger(MyApp.class);
public static void main(final String... args) {
// Set up a simple configuration that logs on the console.
logger.trace("Entering application.");
Bar bar = new Bar();
if (!bar.doIt()) {
logger.error("Didn't do it.");
}
logger.trace("Exiting application.");
}
}
public class Bar {
static final Logger logger = LogManager.getLogger(Bar.class.getName());
public boolean doIt() {
logger.entry();
logger.error("Did it again!");
return logger.exit(false);
}
}
使用log4J2配置
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.foo.Bar" level="trace">
<AppenderRef ref="Console"/>
</Logger>
<Root level="error">
<AppenderRef ref="Console"/>
</Root>
</Loggers>
</Configuration>
应产生以下输出
17:13:01.540 [main] TRACE com.foo.Bar - entry
17:13:01.540 [main] TRACE com.foo.Bar - entry
17:13:01.540 [main] ERROR com.foo.Bar - Did it again!
17:13:01.540 [main] TRACE com.foo.Bar - exit (false)
17:13:01.540 [main] TRACE com.foo.Bar - exit (false)
17:13:01.540 [main] ERROR MyApp - Didn't do it.
然而,运行这个我得到了
00:45:49.951 [main] TRACE com.foo.Bar - entry
00:45:49.951 [main] TRACE com.foo.Bar - entry
00:45:49.951 [main] ERROR com.foo.Bar - Did it again!
00:45:49.951 [main] ERROR com.foo.Bar - Did it again!
00:45:49.951 [main] TRACE com.foo.Bar - exit with(false)
00:45:49.951 [main] TRACE com.foo.Bar - exit with(false)
00:45:49.951 [main] ERROR com.foo.MyApp - Didn't do it.
也就是说,“又做了一次!”记录两次,而不是文档中提到的仅记录一次
# 1 楼答案
只有第一个匹配记录器的日志级别用于接受或拒绝日志事件。一旦它被接受,它将被传递给所有的父日志记录者,不管他们指定了什么级别。我认为文件对此非常清楚,但也许不是