我有一个使用Lombok内置的@ Slf4j记录的Maven项目。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
中间的两行是slf4j记录的那一行。
resources / 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类如下:
@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:
不知道我到底在想什么。任何帮助/提示表示赞赏。
[经过官方apache manual page.亲自弄清楚
我将把整个答案分为以下两个部分
将以下依赖项添加到pom.xml中
<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中
<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。要求使用名称log4j2.xml,因为在classpath中扫描配置会自动将其选中,否则将需要在web.xml中再输入几行来设置配置文件路径。不仅是名称,还必须将配置文件放在web.xml也驻留的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。还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page
最后一点是在Java类中使用记录器。可以将Logger注入到Java类中,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();
}
}
这很好,但是通过在每个类中初始化实例来注入Logger很烦人,因此节省一些工作Slf4j可以提供帮助。 Slf4j只是一个外观(抽象层),在其后面工作的是一个实际的日志记录框架(例如Log4j,Java的内置util.Logger和Logback等)。因此,在将来,如果更好的日志记录框架浮出水面,那么我们就不必接触实例化了日志记录器的Java类,只需根据新需求来照顾依赖项和配置。
除了在案例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批注
@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)并将其注入到类中。
就是这样。很高兴为您提供帮助:)