logback 实现给变量指定默认值
格式是 ${变量名:-默认值}
**光有冒号还不够,再加条短线后面才是默认值**
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< appender name = "info" class = "ch.qos.logback.core.rolling.RollingFileAppender" > < file >/logs${log.folder:-/imeth}/info.log</ file > < rollingPolicy class = "ch.qos.logback.core.rolling.TimeBasedRollingPolicy" > <!-- daily rollover --> < fileNamePattern >/logs${log.folder:-/imeth}/info.%d{yyyy-MM-dd}.log</ fileNamePattern > <!-- keep 30 days worth of history --> < maxHistory >30</ maxHistory > < maxFileSize >${log.file.size.max:-50}MB</ maxFileSize > </ rollingPolicy > < filter class = "ch.qos.logback.classic.filter.LevelFilter" > < level >INFO</ level > < onMatch >ACCEPT</ onMatch > < onMismatch >DENY</ onMismatch > </ filter > <!-- encoders are assigned the type ch.qos.logback.classic.encoder.PatternLayoutEncoder by default --> < encoder > < pattern > [%d{yyyy-MM-dd HH:mm:ss}] [%thread] [%-5level] %logger{35} - %msg%n </ pattern > </ encoder > </ appender > |
logback变量
定义变量
- 在 logback.xml 中定义
- 在命令行定义
- 引入properties文件
在 logback.xml 中定义变量
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<? xml version = "1.0" encoding = "UTF-8" ?> < configuration > < property name = "logBase" value = "/logs" /> ... </ configuration > |
在命令行定义变量
在命令行通过大D参数来定义
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java -DHOME="/home/logstore" xxx.jar |
引入properties文件
在properties文件定义变量。logback引入properties文件后,获得变量。
通过文件路径引入properties文件:
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< configuration > < property file = "/AppPath/logbackVars.properties" /> ... </ configuration > |
通过classpath引入properties文件:
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< configuration > < property resource = "logbackVars.properties" /> ... </ configuration > |
properties文件的格式是 key-value 型:
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HOME=/logs |
变量的作用域
变量有三个作用域:
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local
作用域在配置文件内有效 -
context
作用域的有效范围延伸至 logger context -
system
作用域的范围最广,整个 JVM 内都有效 -
logback
在替换变量时,首先搜索 local 变量,然后搜索 context,然后搜索 system。
如何为变量指定 scope ?
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< configuration > < property scope = "context" name = "home" value = "/logs" /> < appender name = "FILE" class = "ch.qos.logback.core.FileAppender" > < file >/${home}/myApp.log</ file > ... </ appender > ... </ configuration > |
变量的默认值
在引用一个变量时,如果该变量未定义,需要为其指定默认值,写法是:
${变量名:-默认值}
示例:
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<? xml version = "1.0" encoding = "UTF-8" ?> < configuration > < property name = "logBase" value = "${HOME:-/logs}" /> < appender name = "file" class = "ch.qos.logback.core.rolling.RollingFileAppender" > < rollingPolicy class = "ch.qos.logback.core.rolling.TimeBasedRollingPolicy" > < FileNamePattern >${logBase}/log.%d{yyyy-MM-dd}.log</ FileNamePattern > < MaxHistory >60</ MaxHistory > </ rollingPolicy > < encoder > < pattern >%d{yy/MM/dd HH:mm:ss.SSS} %-5level %line %logger{15} - %msg %n</ pattern > < charset >UTF-8</ charset > </ encoder > </ appender > ... </ configuration > |
变量使用
使用方式:
${变量名}
示例:参见前面示例中用法。
以上为个人经验,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/vispin/article/details/50965669