Log4j 的 FileAppender 配置

https://www.bilibili.com/video/BV1iJ411H74S?p=15

log4j.properties

# 指定 RootLogger 顶级父元素默认配置信息
# 指定日志级别=trace，使用的 appender 为 console
log4j.rootLogger = trace,console,file
# 指定控制台日志输出的 appender
log4j.appender.console = org.apache.log4j.ConsoleAppender
# 指定消息格式 layout
log4j.appender.console.layout = org.apache.log4j.PatternLayout
# 指定消息格式的内容
log4j.appender.console.layout.ConversionPattern = [%-10p]%r %l %d{yyyy-MM-dd HH:mm:ss.SSS} %m%n




# 日志文件输出的 appender 对象
log4j.appender.file = org.apache.log4j.FileAppender
# 指定消息格式 layout
log4j.appender.file.layout = org.apache.log4j.PatternLayout
# 指定消息格式的内容
log4j.appender.file.layout.ConversionPattern = [%-10p]%r %l %d{yyyy-MM-dd HH:mm:ss.SSS} %m%n
# 指定日志文件的保存路径
log4j.appender.file.file = /logs/log4j.log
# 指定日志文件的字符集
log4j.appender.file.encoding = UTF-8

log4j.rootLogger = trace,console,file 为 rootLogger 追加了一个 name 为 file 的 appender

log4j.appender.file = org.apache.log4j.FileAppender 声明了一个 name 为 file 的 FileAppender 类型的 appender

log4j.appender.file.file = /logs/log4j.log 通过 OGNL 为 name 为 file 的 appender 指定了属性 file 的值为 “/logs/log4j.log”

log4j.appender.file.encoding = UTF-8 通过 OGNL 为 name 为 file 的 FileAppender 设置继承自父类 WriterAppender 的字符集编码属性 encoding 的值让日志文件不乱码

另外：原来在 Windows 上，log4j.appender.file.file = /logs/log4j.log 中的 “/logs/log4j.log”就指到了程序所在的磁盘根目录“E:\logs\log4j.log”

控制台：

log4j: Trying to find [log4j.xml] using context classloader sun.misc.Launcher$AppClassLoader@18b4aac2.
log4j: Trying to find [log4j.xml] using sun.misc.Launcher$AppClassLoader@18b4aac2 class loader.
log4j: Trying to find [log4j.xml] using ClassLoader.getSystemResource().
log4j: Trying to find [log4j.properties] using context classloader sun.misc.Launcher$AppClassLoader@18b4aac2.
log4j: Using URL [file:/E:/record/2023/2/19/log4j-demo/target/classes/log4j.properties] for automatic log4j configuration.
log4j: Reading configuration from URL file:/E:/record/2023/2/19/log4j-demo/target/classes/log4j.properties
log4j: Parsing for [root] with value=[trace,console,file].
log4j: Level token is [trace].
log4j: Category root set to TRACE
log4j: Parsing appender named "console".
log4j: Parsing layout options for "console".
log4j: Setting property [conversionPattern] to [[%-10p]%r %l %d{yyyy-MM-dd HH:mm:ss.SSS} %m%n].
log4j: End of parsing for "console".
log4j: Parsed "console" options.
log4j: Parsing appender named "file".
log4j: Parsing layout options for "file".
log4j: Setting property [conversionPattern] to [[%-10p]%r %l %d{yyyy-MM-dd HH:mm:ss.SSS} %m%n].
log4j: End of parsing for "file".
log4j: Setting property [encoding] to [UTF-8].
log4j: Setting property [file] to [/logs/log4j.log].
log4j: setFile called: /logs/log4j.log, true
log4j: setFile ended
log4j: Parsed "file" options.
log4j: Finished configuring.
[INFO      ]0 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:24) 2023-02-24 17:46:59.040 hello log4j
[FATAL     ]2 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:27) 2023-02-24 17:46:59.042 fatal
[ERROR     ]2 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:29) 2023-02-24 17:46:59.042 error
[WARN      ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:30) 2023-02-24 17:46:59.043 warn
[INFO      ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:31) 2023-02-24 17:46:59.043 info
[DEBUG     ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:32) 2023-02-24 17:46:59.043 debug
[DEBUG     ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:34) 2023-02-24 17:46:59.043 trace

Process finished with exit code 0

“E:\logs\log4j.log”:

[INFO      ]0 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:24) 2023-02-24 17:46:59.040 hello log4j
[FATAL     ]2 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:27) 2023-02-24 17:46:59.042 fatal
[ERROR     ]2 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:29) 2023-02-24 17:46:59.042 error
[WARN      ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:30) 2023-02-24 17:46:59.043 warn
[INFO      ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:31) 2023-02-24 17:46:59.043 info
[DEBUG     ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:32) 2023-02-24 17:46:59.043 debug
[DEBUG     ]3 io.github.jihch.Log4jTest.testQuick(Log4jTest.java:34) 2023-02-24 17:46:59.043 trace

RollingFileAppender

按照文件大小进行拆分，超过一定的大小就会拆分成多个文件

DailyRollingFileAppender

按照时间规则对文件进行拆分