in spring boot project we can write logging.level.root=WARN but here problem is, we have to restart again even we added devtools dependency, in property file if we are modified any value will not autodetectable, for this limitation i came to know the solution i,e we can add actuator in pom.xml and pass the logger level as below shown in postman client in url bar http://localhost:8080/loggers/ROOT or http://localhost:8080/loggers/com.mycompany and in the body you can pass the json format like below

{
  "configuredLevel": "WARN"
}

现有的答案很好。我只是想与您分享一个新的spring引导功能，允许对日志进行分组并在整个组上设置日志级别。

来自文件的例子:

创建日志记录组

logging.group.tomcat=org.apache.catalina, org.apache.coyote, org.apache.tomcat

为组设置日志级别

logging.level.tomcat=TRACE

这是一个很好的功能，它带来了更多的灵活性。

如果您想使用不同的日志框架(例如log4j)，我发现最简单的方法是禁用spring引导自己的日志记录并实现自己的日志记录。这样我就可以在一个文件log4j.xml(在我的例子中)中配置每个日志级别。

要实现这一点，你只需要将这些行添加到你的pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j</artifactId>
</dependency>

您可能已经有了第一个依赖项，只需要另外两个依赖项。请注意，这个例子只包含log4j。 以上就是全部内容，现在您就可以在log4j配置文件中为引导配置日志了!

in spring boot project we can write logging.level.root=WARN but here problem is, we have to restart again even we added devtools dependency, in property file if we are modified any value will not autodetectable, for this limitation i came to know the solution i,e we can add actuator in pom.xml and pass the logger level as below shown in postman client in url bar http://localhost:8080/loggers/ROOT or http://localhost:8080/loggers/com.mycompany and in the body you can pass the json format like below

{
  "configuredLevel": "WARN"
}

记录:官方文档，如Spring Boot v1.2.0。RELEASE和Spring v4.1.3 RELEASE:

If the only change you need to make to logging is to set the levels of various loggers then you can do that in application.properties using the "logging.level" prefix, e.g. logging.level.org.springframework.web: DEBUG logging.level.org.hibernate: ERROR You can also set the location of a file to log to (in addition to the console) using "logging.file". To configure the more fine-grained settings of a logging system you need to use the native configuration format supported by the LoggingSystem in question. By default Spring Boot picks up the native configuration from its default location for the system (e.g. classpath:logback.xml for Logback), but you can set the location of the config file using the "logging.config" property.

根据文档，您可以根据java包拥有不同的日志级别。

 logging.level.com.mypackage.myproject=WARN
 logging.level.org.springframework=DEBUG
 logging.level.root=INFO 

这就意味着

对于您的自定义包com.mypackage.myproject将应用WARN日志级别 对于spring框架包org。将应用springframework DEBUG日志级别 对于每个其他包，将应用INFO日志级别

您还可以将不同的java包分组在一起，并指示系统在一行中对该组的所有包使用相同的日志级别。

在前面的例子中你可以这样做

 logging.level.root=INFO 
 logging.level.org.springframework=DEBUG
 
 logging.group.myCustomGroup = com.mypackage.myproject, com.otherpackage.otherproject, com.newpackage.newproject
 logging.level.myCustomGroup=WARN

这就意味着包裹

com.mypackage.myproject com.otherpackage.otherproject com.newpackage.newproject

是否所有日志级别都应用了WARN