使用 JDK Logging
package com.demo; import java.util.logging.Logger; public class Main { public static void main(String[] args) { Logger logger = Logger.getLogger(Main.class.getName()); logger.info("info"); } }
输出
八月 06, 2020 5:39:42 下午 com.demo.Main main 信息: info • 1 • 2
使用 commons-logging
依赖
<dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.2</version> </dependency>
示例
package com.demo; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class Main { public static void main(String[] args) { Log log = LogFactory.getLog(Main.class); log.info("info"); } }
使用 log4j
关系：
- Commons Logging 日志接口
- Log4j 日志实现
依赖
<!--commons-logging--> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.2</version> </dependency> <!--log4j--> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-core</artifactId> <version>2.13.3</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-api</artifactId> <version>2.13.3</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-jcl</artifactId> <version>2.13.3</version> </dependency>
日志配置 log4j2.xml
<?xml version="1.0" encoding="UTF-8"?> <Configuration> <Properties> <!-- 定义日志格式 --> <Property name="log.pattern">%d{MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{36}%n%msg%n%n</Property> <!-- 定义文件名变量 --> <Property name="file.err.filename">log/err.log</Property> <Property name="file.err.pattern">log/err.%i.log.gz</Property> </Properties> <!-- 定义Appender，即目的地 --> <Appenders> <!-- 定义输出到屏幕 --> <Console name="console" target="SYSTEM_OUT"> <!-- 日志格式引用上面定义的log.pattern --> <PatternLayout pattern="${log.pattern}" /> </Console> <!-- 定义输出到文件,文件名引用上面定义的file.err.filename --> <RollingFile name="err" bufferedIO="true" fileName="${file.err.filename}" filePattern="${file.err.pattern}"> <PatternLayout pattern="${log.pattern}" /> <Policies> <!-- 根据文件大小自动切割日志 --> <SizeBasedTriggeringPolicy size="1 MB" /> </Policies> <!-- 保留最近10份 --> <DefaultRolloverStrategy max="10" /> </RollingFile> </Appenders> <Loggers> <Root level="info"> <!-- 对info级别的日志，输出到console --> <AppenderRef ref="console" level="info" /> <!-- 对error级别的日志，输出到err，即上面定义的RollingFile --> <AppenderRef ref="err" level="error" /> </Root> </Loggers> </Configuration>
使用示例
package com.demo; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; public class Main { public static void main(String[] args) { Log log = LogFactory.getLog(Main.class); log.info("info"); log.error("error"); } }
SLF4J和Logback
关系
- SLF4J 日志接口
- Logback 日志的实现
Simple Logging Facade for Java (SLF4J)
依赖
<!--logback--> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>1.7.30</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-core</artifactId> <version>1.2.3</version> </dependency>
配置文件logback.xml
<?xml version="1.0" encoding="UTF-8"?> <configuration> <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender"> <encoder> <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern> </encoder> </appender> <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender"> <encoder> <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern> <charset>utf-8</charset> </encoder> <file>log/output.log</file> <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy"> <fileNamePattern>log/output.log.%i</fileNamePattern> </rollingPolicy> <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy"> <MaxFileSize>1MB</MaxFileSize> </triggeringPolicy> </appender> <root level="INFO"> <appender-ref ref="CONSOLE" /> <appender-ref ref="FILE" /> </root> </configuration>
示例
package com.demo; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Main { public static void main(String[] args) { Logger log = LoggerFactory.getLogger(Main.class); log.info("info"); log.error("error"); } }
