log4j

最新推荐文章于 2024-10-16 10:42:54 发布

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最新推荐文章于 2024-10-16 10:42:54 发布

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本文链接：https://blog.youkuaiyun.com/begin27/article/details/51376569

本文详细介绍了如何配置和使用log4j进行日志输出，包括控制台输出、文件输出以及不同级别的日志记录，并通过示例代码展示了如何在Java中应用这些配置。

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log4j.properties

#设置
log4j.rootLogger = debug,stdout,D,E

#输出信息到控制台
log4j.appender.stdout = org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target = System.out
log4j.appender.stdout.layout = org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n

#输出DEBUG 级别以上的日志到=E://logs/error.log
log4j.appender.D = org.apache.log4j.DailyRollingFileAppender
log4j.appender.D.File = E://logs/log.log
log4j.appender.D.Append = true
log4j.appender.D.Threshold = DEBUG
log4j.appender.D.layout = org.apache.log4j.PatternLayout
log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] - [ %p ] %m%n

#输出ERROR 级别以上的日志到=E://logs/error.log
log4j.appender.E = org.apache.log4j.DailyRollingFileAppender
log4j.appender.E.File =E\://logs/error.log
log4j.appender.E.Append = true
log4j.appender.E.Threshold = ERROR
log4j.appender.E.layout = org.apache.log4j.PatternLayout
log4j.appender.E.layout.ConversionPattern =%-d{yyyy-MM-dd HH\:mm\:ss} [ %t\:%r ] - [ %p ]

注意：.properties属性文件编码格式要设置为GBK，否则会出现乱码

上代码

import org.apache.log4j.Logger;
public class Test
{
private static Logger logger = Logger.getLogger(Test.class);
public static void main(String[] args)
{
// 记录debug级别的信息
logger.debug("This is debug message.");
// 记录info级别的信息
logger.info("This is info message.");
// 记录error级别的信息
logger.error("This is error message.");
try
{
System.out.println(1 / 0);
}
catch (Exception e)
{
logger.error(e.getMessage());
}
try
{
int[] haha = new int[2];
int a = haha[3];
}
catch (Exception e)
{
logger.error("error", e);

}
}
}

控制台输出如下：

[DEBUG] 2016-05-11 17:39:14,374 method:com.Test.main(Test.java:10)
This is debug message.
[INFO ] 2016-05-11 17:39:14,377 method:com.Test.main(Test.java:12)
This is info message.
[ERROR] 2016-05-11 17:39:14,377 method:com.Test.main(Test.java:14)
This is error message.
[ERROR] 2016-05-11 17:39:14,377 method:com.Test.main(Test.java:21)
/ by zero
[ERROR] 2016-05-11 17:39:14,378 method:com.Test.main(Test.java:30)
error
java.lang.ArrayIndexOutOfBoundsException: 3
at com.Test.main(Test.java:26)

在E盘logs文件夹下有2个文件error.log和log.log

error.log内容如下

2016-05-11 16:14:42 [ main:2 ] - [ ERROR ] 2016-05-11 16:14:42 [ main:3 ] - [ ERROR ] java.lang.ArithmeticException: / by zero
at com.Test.main(Test.java:21)
2016-05-11 16:14:42 [ main:5 ] - [ ERROR ] java.lang.ArrayIndexOutOfBoundsException: 3
at com.Test.main(Test.java:31)
2016-05-11 17:39:14 [ main:3 ] - [ ERROR ] 2016-05-11 17:39:14 [ main:3 ] - [ ERROR ] 2016-05-11 17:39:14 [ main:4 ] - [ ERROR ] java.lang.ArrayIndexOutOfBoundsException: 3
at com.Test.main(Test.java:26)

log.log内容如下

2016-05-11 16:14:42 [ main:0 ] - [ DEBUG ] This is debug message.
2016-05-11 16:14:42 [ main:2 ] - [ INFO ] This is info message.
2016-05-11 16:14:42 [ main:2 ] - [ ERROR ] This is error message.
2016-05-11 16:14:42 [ main:3 ] - [ ERROR ] error
java.lang.ArithmeticException: / by zero
at com.Test.main(Test.java:21)
2016-05-11 16:14:42 [ main:5 ] - [ ERROR ] error
java.lang.ArrayIndexOutOfBoundsException: 3
at com.Test.main(Test.java:31)
2016-05-11 17:39:14 [ main:0 ] - [ DEBUG ] This is debug message.
2016-05-11 17:39:14 [ main:3 ] - [ INFO ] This is info message.
2016-05-11 17:39:14 [ main:3 ] - [ ERROR ] This is error message.
2016-05-11 17:39:14 [ main:3 ] - [ ERROR ] / by zero
2016-05-11 17:39:14 [ main:4 ] - [ ERROR ] error
java.lang.ArrayIndexOutOfBoundsException: 3
at com.Test.main(Test.java:26)