日志是应用软件中不可缺少的部分,Apache的开源项目log4j是一个功能强大的日志组件,提供方便的日志记录。
apache下载log4j:https://logging.apache.org/log4j/2.x/download.html
一、导入log4j的包:
1)下载jar包放到lib中。
2)maven下载依赖:
<dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-core</artifactId> <version>2.11.0</version> </dependency> <dependency> <groupId>org.apache.logging.log4j</groupId> <artifactId>log4j-api</artifactId> <version>2.11.0</version> </dependency>
二、编写配置文件:
1)配置log4j.properties
### 设置### log4j.rootLogger = debug,stdout,D,E ### 输出信息到控制抬 ### 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 = [%-5p] %d{yyyy-MM-dd HH:mm:ss,SSS} method:%l%n%m%n ### 输出DEBUG 级别以上的日志到=G://logs/error.log ### log4j.appender.D = org.apache.log4j.DailyRollingFileAppender log4j.appender.D.File = G://logs/log.log log4j.appender.D.Append = true log4j.appender.D.Threshold = DEBUG log4j.appender.D.layout = org.apache.log4j.PatternLayout log4j.appender.D.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [ %l] - [ %p ] %m%n ### 输出ERROR 级别以上的日志到=G://logs/error.log ### log4j.appender.E = org.apache.log4j.DailyRollingFileAppender log4j.appender.E.File =G://logs/error.log log4j.appender.E.Append = true log4j.appender.E.Threshold = ERROR log4j.appender.E.layout = org.apache.log4j.PatternLayout log4j.appender.E.layout.ConversionPattern = %-d{yyyy-MM-dd HH:mm:ss} [%l] - [ %p ] %m%n
1)配置log4j2.xml
<?xml version="1.0" encoding="UTF-8"?> <configuration status="WARN" monitorInterval="30"> <!--定义所有的appender --> <appenders> <!--这个输出控制台的配置 --> <console name="Console" target="SYSTEM_OUT"> <!--输出日志的格式 --> <PatternLayout pattern="[%d{HH:mm:ss:SSS}] [%p] - %l -%n%m%n" /> </console> <!-- 这个会打印出所有的info及以下级别的信息,每次大小超过size,则这size大小的日志会自动存入按年份-月份建立的文件夹下面并进行压缩,作为存档 --> <RollingFile name="RollingFileInfo" fileName="G://log2/info.log" filePattern="G://log2/$${date:yyyy-MM}/info-%d{yyyy-MM-dd}-%i.log"> <!--控制台只输出level及以上级别的信息(onMatch),其他的直接拒绝(onMismatch) --> <ThresholdFilter level="info" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n" /> <Policies> <TimeBasedTriggeringPolicy /> <SizeBasedTriggeringPolicy size="10MB" /> </Policies> </RollingFile> <RollingFile name="RollingFileWarn" fileName="G://log2/warn.log" filePattern="G://log2/$${date:yyyy-MM}/warn-%d{yyyy-MM-dd}-%i.log"> <ThresholdFilter level="warn" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n" /> <Policies> <TimeBasedTriggeringPolicy /> <SizeBasedTriggeringPolicy size="10MB" /> </Policies> <!-- DefaultRolloverStrategy属性如不设置,则默认为最多同一文件夹下7个文件,这里设置了10 --> <DefaultRolloverStrategy max="10" /> </RollingFile> <RollingFile name="RollingFileError" fileName="G://log2/error.log" filePattern="G://log2/$${date:yyyy-MM}/error-%d{yyyy-MM-dd}-%i.log"> <ThresholdFilter level="error" onMatch="ACCEPT" onMismatch="DENY" /> <PatternLayout pattern="[%d{HH:mm:ss:SSS}] [%p] - %l - %m%n" /> <Policies> <TimeBasedTriggeringPolicy /> <SizeBasedTriggeringPolicy size="10MB" /> </Policies> </RollingFile> </appenders> <!--然后定义logger,只有定义了logger并引入的appender,appender才会生效 --> <loggers> <!--过滤掉spring和mybatis的一些无用的DEBUG信息 --> <logger name="org.springframework" level="INFO"></logger> <logger name="org.mybatis" level="INFO"></logger> <root level="all"> <appender-ref ref="Console" /> <appender-ref ref="RollingFileInfo" /> <appender-ref ref="RollingFileWarn" /> <appender-ref ref="RollingFileError" /> </root> </loggers> </configuration>
三、编写代码:
1)Log4j.java (注意:导入Logger的jar包和Logger的获取方式)
package com.lris.test; import org.apache.log4j.Logger; public class Log4j { private static Logger logger = Logger.getLogger(Test.class); public static void main(String[] args) { // 记录debug级别的信息 logger.debug("This is debug message!"); // 记录info级别的信息 logger.info("This is info message!"); // 记录error级别的信息 logger.error("This is error message!"); // 记录warn级别的信息 logger.warn("This is warn message!"); } }
2)Log4j2.java (注意:导入Logger的jar包和Logger的获取方式)
package com.lris.test; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; public class Log4j2 { private static Logger logger2 = LogManager.getLogger(Test.class); public static void main(String[] args) { // 记录debug级别的信息 logger2.debug("This is debug message!"); // 记录info级别的信息 logger2.info("This is info message!"); // 记录error级别的信息 logger2.error("This is error message!"); // 记录warn级别的信息 logger2.warn("This is warn message!"); } }