[英]@SLF4J : How to configure lombok supported slf4j
我有一个 maven 项目,它使用 Lombok 的内置 @Slf4j 进行记录。 目前我的日志在控制台中可见,如下所示
06-Apr-2020 17:42:38.217 INFO [RMI TCP Connection(2)-127.0.0.1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
[2020-04-06 05:42:40,701] Artifact Tarkshala-Scholars-Engine:war exploded: Artifact is deployed successfully
[2020-04-06 05:42:40,701] Artifact Tarkshala-Scholars-Engine:war exploded: Deploy took 4,521 milliseconds
[http-nio-8080-exec-1] INFO com.tarkshala.scholars.engine.webservices.AuthenticationService - Welcome to Tarkshala Scholar APIs
[http-nio-8080-exec-3] INFO com.tarkshala.scholars.engine.webservices.AuthenticationService - Welcome to Tarkshala Scholar APIs
06-Apr-2020 17:42:45.808 INFO [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [/Users/kuldeep/Work/apps/apache-tomcat-9/webapps/manager]
06-Apr-2020 17:42:45.843 INFO [Catalina-utility-2] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [/Users/kuldeep/Work/apps/apache-tomcat-9/webapps/manager] has finished in [35] ms
中间的一对线是 slf4j 记录的。
资源/log4j.properties 如下所示
# Root logger option
log4j.rootLogger=DEBUG, stdout, file
# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
# Redirect log messages to a log file, support file rolling.
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=/Users/kuldeep/Work/repos/Tarkshala-Scholars-APIs/logs/application.log
log4j.appender.file.MaxFileSize=5MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n
pom.xml 如下所示:
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.30</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-simple</artifactId>
<version>1.7.30</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.10</version>
<scope>provided</scope>
</dependency>
Java class 看起来像这样:
@Slf4j
@Path("/authentication")
@Authorization
public class AuthenticationService extends SpringApplication {
@Path("/greet")
@GET
@Produces(MediaType.TEXT_PLAIN)
@PubliclyAllowed
public Response greet(){
log.info("Welcome to Tarkshala Scholar APIs");
return getBean(AuthenticationServiceHandler.class).greet();
}
}
我有几个问题:
不知道我到底错过了什么。 任何帮助/提示表示赞赏。
在浏览了官方apache 手册页后,我自己弄清楚了。
我将把整个答案分成以下两个部分
将以下依赖项添加到 pom.xml
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.13.1</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.13.1</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-web</artifactId>
<version>2.13.1</version>
</dependency>
将以下过滤器添加到 web.xml
<filter>
<filter-name>log4jServletFilter</filter-name>
<filter-class>org.apache.logging.log4j.web.Log4jServletFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>log4jServletFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
一个配置文件 log4j2.xml。 需要遵循名称 log4j2.xml,因为扫描类路径中的配置会自动拾取它,否则 web.Z0F635D0E0F3874FFF8B581C132E6C7 中的配置文件将需要设置为7。 不仅仅是名称,配置文件必须放在 web.xml 所在的 WEB-INF 目录中。
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="DEBUG">
<Appenders>
<Console name="LogToConsole" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
<RollingRandomAccessFile name="LogToRollingRandomAccessFile" fileName="logs/TSE-app.log"
filePattern="logs/$${date:yyyy-MM}/app-%d{MM-dd-yyyy}-%i.log.gz">
<PatternLayout>
<Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
</PatternLayout>
<Policies>
<TimeBasedTriggeringPolicy/>
<SizeBasedTriggeringPolicy size="1 MB"/>
</Policies>
<DefaultRolloverStrategy max="10"/>
</RollingRandomAccessFile>
</Appenders>
<Loggers>
<!-- avoid duplicated logs with additivity=false -->
<Logger name="com.tarkshala.scholars" level="debug" additivity="false">
<AppenderRef ref="LogToConsole"/>
<AppenderRef ref="LogToRollingRandomAccessFile"/>
</Logger>
<Root level="error">
<AppenderRef ref="LogToRollingRandomAccessFile"/>
<AppenderRef ref="LogToConsole"/>
</Root>
</Loggers>
</Configuration>
上面给出的配置包含两种类型的记录器,第一种用于控制台,第二种用于文件。 也可以为单个记录器指定日志级别。 有关日志模式等更多信息,请遵循 apache 的手册页
最后一点是在 java class 中使用记录器。 记录器可以注入到 java class 中,如下所示:
@Path("/authentication")
public class AuthenticationService extends SpringApplication {
private Logger logger = LogManager.getLogger(AuthenticationService.class);
@Path("/greet")
@GET
@Produces(MediaType.TEXT_PLAIN)
public Response greet(){
logger.info("Welcome to Tarkshala Scholar APIs");
logger.error("THis is error log");
logger.debug("THis is debug log");
return getBean(AuthenticationServiceHandler.class).greet();
}
}
这工作正常,但通过在每个 class 中初始化实例来注入 Logger 很烦人,所以为了节省一些工作 Slf4j 可以提供帮助。 Slf4j 只是一个外观(抽象层),其背后是一个实际的日志框架(如 Log4j,Java 的内置 util.Logger 和 Logback 等)。 因此,如果将来出现更好的日志记录框架,那么我们将不必触及已实例化记录器的 java 类,只需根据新需求处理依赖项和配置。
除了我们在案例 1 中所做的所有工作之外,我们还需要添加更多的依赖项。
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.13.1</version>
</dependency>
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-slf4j-impl</artifactId>
<version>2.13.1</version>
</dependency>
使用 Lombok 注释@Slf4j
注入记录器非常容易。
@Path("/authentication")
@Slf4j
public class AuthenticationService extends SpringApplication {
private Logger logger = LogManager.getLogger(AuthenticationService.class);
@Path("/greet")
@GET
@Produces(MediaType.TEXT_PLAIN)
public Response greet(){
log.info("Welcome to Tarkshala Scholar APIs");
log.error("THis is error log");
log.debug("THis is debug log");
return getBean(AuthenticationServiceHandler.class).greet();
}
}
Lombok 负责初始化记录器实例( log
对象)并将其注入 class。
就是这样。 乐意效劳:)
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