logger

# 查看logger
[arthas@21536]$ logger
name                                   ROOT
class                                  ch.qos.logback.classic.Logger
classLoader                            sun.misc.Launcher$AppClassLoader@18b4aac2
classLoaderHash                        18b4aac2
level                                  INFO
effectiveLevel                         INFO
additivity                             true
codeSource                             file:/D:/.m2/repository/ch/qos/logback/logback-classic/1.2.5/logback-classic-1.2.5.jar
appenders                              name            STDOUT
                                       class           ch.qos.logback.core.ConsoleAppender
                                       classLoader     sun.misc.Launcher$AppClassLoader@18b4aac2
                                       classLoaderHash 18b4aac2
                                       target          System.out

# 指定名字查看logger
[arthas@21536]$ logger -n org.springframework
name                                   org.springframework
class                                  ch.qos.logback.classic.Logger
classLoader                            sun.misc.Launcher$AppClassLoader@18b4aac2
classLoaderHash                        18b4aac2
level                                  WARN
effectiveLevel                         WARN
additivity                             true
codeSource                             file:/D:/.m2/repository/ch/qos/logback/logback-classic/1.2.5/logback-classic-1.2.5.jar

# 查看指定ClassLoader的logger
[arthas@21536]$ logger -c 18b4aac2
name                                   ROOT
class                                  ch.qos.logback.classic.Logger
classLoader                            sun.misc.Launcher$AppClassLoader@18b4aac2
classLoaderHash                        18b4aac2
level                                  INFO
effectiveLevel                         INFO
additivity                             true
codeSource                             file:/D:/.m2/repository/ch/qos/logback/logback-classic/1.2.5/logback-classic-1.2.5.jar
appenders                              name            STDOUT
                                       class           ch.qos.logback.core.ConsoleAppender
                                       classLoader     sun.misc.Launcher$AppClassLoader@18b4aac2
                                       classLoaderHash 18b4aac2
                                       target          System.out

# 设置日志级别
[arthas@21536]$ logger -n org.springframework -l DEBUG
Update logger level success.

# 指定 classloader 更新 logger level
# 默认情况下，logger 命令会在 SystemClassloader 下执行，
# 如果应用是传统的war应用，或者 spring boot fat jar 启动的应用，那么需要指定 classloader。
[arthas@21536]$ logger -c 18b4aac2 -n ROOT -l DEBUG
Update logger level success.