日志打印

logger.debug("Processing trade with id: {} and symbol : {} ", id, symbol);  
logger.info("{}.{} 接收参数: {}", classNm, method, JSON.toJSONString(params));

打印级别设置：
可以按模块、包来设置不同的级别
写在前面的生效，后面的不生效

#logging.level.com.cashew.parking.repository: debug

控制台查看springboot自动配置的服务
debug: true

log4j

Log4j根据日志信息的重要程度，分OFF、FATAL、ERROR、WARN、INFO、DEBUG、ALL
rootLogger，即使没有显示配置也是存在的，并且默认输出级别为DEBUG
所有其他的Logger都默认继承自rootLogger
log4j.rootLogger = [ level ] , appenderName, appenderName, …
把指定级别以上的日志信息输出到指定的一个或者多个位置
import org.apache.log4j.Logger;
Logger log = Logger.getLogger(this.getClass());
log4j.properties：

log4j.rootLogger=INFO,logfile,stdout  

log4j.appender.logfile=org.apache.log4j.DailyRollingFileAppender  
log4j.appender.logfile.DatePattern='.'yyyy-MM-dd  
log4j.appender.logfile.File=d:/logs/calf.log  
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout  
log4j.appender.logfile.layout.ConversionPattern=[%d{ISO8601}|%t|%-5p|%C] - %m%n  
log4j.appender.logfile.encoding=UTF-8
#console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=[%d{HH:mm:ss}|%-5p|%c] - %m%n  
#show application DEBUG log
log4j.logger.com.asecs = DEBUG,logfile 
#show ibatis DEBUG log
log4j.logger.com.ibatis = DEBUG    
log4j.logger.com.ibatis.common.jdbc.SimpleDataSource = DEBUG    
log4j.logger.com.ibatis.common.jdbc.ScriptRunner = DEBUG    
log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate = DEBUG    
log4j.logger.java.sql.Connection = DEBUG    
log4j.logger.java.sql.Statement = DEBUG    
log4j.logger.java.sql.PreparedStatement = DEBUG  
log4j.logger.java.sql.ResultSet = DEBUG 

calf.log
calf.log.2017-12-25

按级别分文件打印日志

DailyRollingFileAppender特点是固定周期时间生成一个日志文件，比如，默认情况是每天生成一个文件。这种日志可以方便根据时间来定位日志位置，使日志清晰易查。但是这种日志有个不好地方是，不能限制日志数量参考

# priority  :debug<info<warn<error
#you cannot specify every priority with different file for log4j
log4j.rootLogger=debug,stdout,info,debug,warn,error 

#console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender 
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout 
log4j.appender.stdout.layout.ConversionPattern= [%d{yyyy-MM-dd HH:mm:ss a}]:%p %l%m%n
#info log
log4j.logger.info=info
log4j.appender.info=org.apache.log4j.DailyRollingFileAppender 
log4j.appender.info.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.info.File=d:/logs/calf/info.log
log4j.appender.info.Append=true
log4j.appender.info.Threshold=INFO
log4j.appender.info.layout=org.apache.log4j.PatternLayout 
log4j.appender.info.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#debug log
log4j.logger.debug=debug
log4j.appender.debug=org.apache.log4j.DailyRollingFileAppender 
log4j.appender.debug.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.debug.File=d:/logs/calf/debug.log
log4j.appender.debug.Append=true
log4j.appender.debug.Threshold=DEBUG
log4j.appender.debug.layout=org.apache.log4j.PatternLayout 
log4j.appender.debug.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#warn log
log4j.logger.warn=warn
log4j.appender.warn=org.apache.log4j.DailyRollingFileAppender 
log4j.appender.warn.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.warn.File=d:/logs/calf/warn.log
log4j.appender.warn.Append=true
log4j.appender.warn.Threshold=WARN
log4j.appender.warn.layout=org.apache.log4j.PatternLayout 
log4j.appender.warn.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n
#error
log4j.logger.error=error
log4j.appender.error = org.apache.log4j.DailyRollingFileAppender
log4j.appender.error.DatePattern='_'yyyy-MM-dd'.log'
log4j.appender.error.File = d:/logs/calf/error.log 
log4j.appender.error.Append = true
log4j.appender.error.Threshold = ERROR 
log4j.appender.error.layout = org.apache.log4j.PatternLayout
log4j.appender.error.layout.ConversionPattern = %d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c >> Method: %l ]%n%p:%m%n

过滤器的使用

更多相关东西

xml配置

使用log4j.xml详细配置
即使用过滤器

        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="DEBUG"/>
            <param name="LevelMax" value="DEBUG"/>
        </filter>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration>

    <!-- ========================== 自定义输出格式说明================================ -->
    <!-- %p 输出优先级，即DEBUG，INFO，WARN，ERROR，FATAL -->
    <!-- %r 输出自应用启动到输出该log信息耗费的毫秒数  -->
    <!-- %c 输出所属的类目，通常就是所在类的全名 -->
    <!-- %t 输出产生该日志事件的线程名 -->
    <!-- %n 输出一个回车换行符，Windows平台为“/r/n”，Unix平台为“/n” -->
    <!-- %d 输出日志时间点的日期或时间，默认格式为ISO8601，也可以在其后指定格式，比如：%d{yyy MMM dd HH:mm:ss,SSS}，输出类似：2002年10月18日 22：10：28，921  -->
    <!-- %l 输出日志事件的发生位置，包括类目名、发生的线程，以及在代码中的行数。举例：Testlo4.main(TestLog4.java:10)  -->
    <!-- ========================================================================== -->

    <!-- ========================== 输出方式说明================================ -->
    <!-- Log4j提供的appender有以下几种:  -->
    <!-- org.apache.log4j.ConsoleAppender(控制台),  -->
    <!-- org.apache.log4j.FileAppender(文件),  -->
    <!-- org.apache.log4j.DailyRollingFileAppender(每天产生一个日志文件), -->
    <!-- org.apache.log4j.RollingFileAppender(文件大小到达指定尺寸的时候产生一个新的文件),  -->
    <!-- org.apache.log4j.WriterAppender(将日志信息以流格式发送到任意指定的地方)   -->
    <!-- ========================================================================== -->

    <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
        <!-- <param name="Target" value="System.out"/> -->
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c  Method: %l ]%n%p:%m%n"/>
        </layout>
        <!--  <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="DEBUG"/>
            <param name="LevelMax" value="DEBUG"/>
        </filter> -->
    </appender>
    <!-- output the debug   -->
    <!--  <appender name="log4jDebug" class="org.apache.log4j.DailyRollingFileAppender">
         <param name="File" value="log_"/>
          <param name="append" value="true" />
         <param name="MaxFileSize" value="KB"/>
         <param name="MaxBackupIndex" value="2"/> -->
    <appender name="log4jDebug"  class="org.apache.log4j.rolling.RollingFileAppender">
        <param name="Append" value="true"/>
        <rollingPolicy  class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
            <param name="FileNamePattern" value="d:/logs/calfxml/debug_%d{yyyy-MM-dd}.log" />
        </rollingPolicy>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c Method: %l ]%n%p:%m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="DEBUG"/>
            <param name="LevelMax" value="DEBUG"/>
        </filter>
    </appender>
    <!--  <appender name="log4jInfo" class="org.apache.log4j.DailyRollingFileAppender">
         <param name="File" value="log_"/>
         <param name="DatePattern" value="'.log'yyyy-MM-dd"/>
         <param name="Append" value="true"/>
        <param name="MaxFileSize" value="5KB"/>
         <param name="MaxBackupIndex" value="2"/> -->
    <appender name="log4jInfo"  class="org.apache.log4j.rolling.RollingFileAppender">
        <param name="Append" value="true"/>
        <rollingPolicy  class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
            <param name="FileNamePattern" value="d:/logs/calfxml/info_%d{yyyy-MM-dd}.log" />
        </rollingPolicy>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c  Method: %l ]%n%p:%m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="INFO"/>
            <param name="LevelMax" value="INFO"/>
        </filter>
    </appender>
    <!--  <appender name="log4jWarn" class="org.apache.log4j.DailyRollingFileAppender">
         <param name="File" value="/log_"/>
         <param name="DatePattern" value="'.log'yyyy-MM-dd"/>
         <param name="Append" value="true"/>
         <param name="MaxFileSize" value="5KB"/>
         <param name="MaxBackupIndex" value="2"/> -->
    <appender name="log4jWarn" class="org.apache.log4j.rolling.RollingFileAppender">
        <param name="Append" value="true"/>
        <rollingPolicy  class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
            <param name="FileNamePattern" value="d:/logs/calfxml/warn_%d{yyyy-MM-dd}.log" />
        </rollingPolicy>
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c Method: %l ]%n%p:%m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="WARN"/>
            <param name="LevelMax" value="WARN"/>
        </filter>
    </appender>
    <!--  <appender name="log4jError" class="org.apache.log4j.DailyRollingFileAppender"> -->
    <appender name="log4jError"  class="org.apache.log4j.rolling.RollingFileAppender">
        <!--  <param name="File" value="/error_"/>
         <param name="DatePattern" value="'.log'yyyy-MM-dd"/> -->
        <param name="Append" value="true"/>
        <rollingPolicy  class="org.apache.log4j.rolling.TimeBasedRollingPolicy">
            <param name="FileNamePattern" value="d:/logs/calfxml/error_%d{yyyy-MM-dd}.log" />
        </rollingPolicy>

        <!--   <param name="MaxFileSize" value="5KB"/> -->
        <!--   <param name="MaxBackupIndex" value="2"/> -->
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss a} [Thread: %t][ Class:%c Method: %l ]%n%p:%m%n"/>
        </layout>
        <filter class="org.apache.log4j.varia.LevelRangeFilter">
            <param name="LevelMin" value="ERROR"/>
            <param name="LevelMax" value="ERROR"/>
        </filter>
    </appender>
    <!--通过<category></category>的定义可以将各个包中的类日志输出到不同的日志文件中-->
    <!--     <category name="com.gzy">
            <priority value="debug" />
            <appender-ref ref="log4jTestLogInfo" />
            <appender-ref ref="log4jTestDebug" />
        </category> -->
    <appender name="MAIL"
              class="org.apache.log4j.net.SMTPAppender">
        <param name="threshold" value="debug" />
        <!-- 日志的错误级别
         <param name="threshold" value="error"/>
        -->
        <!-- 缓存文件大小，日志达到512K时发送Email -->
        <param name="BufferSize" value="512" /><!-- 单位K -->
        <param name="From" value="wsyyolo@163.com" />
        <param name="SMTPHost" value="smtp.163.com" />
        <param name="Subject" value="juyee-log4jMessage" />
        <param name="To" value="wsyyolo@163.com" />
        <param name="SMTPUsername" value="test" />
        <param name="SMTPPassword" value="test" />
        <layout class="org.apache.log4j.PatternLayout">
            <param name="ConversionPattern"
                   value="%-d{yyyy-MM-dd HH:mm:ss.SSS a} [%p]-[%c] %m%n" />
        </layout>
    </appender>


    <root>
        <priority value="debug"/>
        <appender-ref ref="CONSOLE" />
        <appender-ref ref="log4jDebug" />
        <appender-ref ref="log4jInfo" />
        <appender-ref ref="log4jWarn" />
        <appender-ref ref="log4jError" />
        <!-- <appender-ref ref="MAIL" /> -->
    </root>
</log4j:configuration>

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https://www.cnblogs.com/zsty/p/10608953.html