1. Preparation of components before use:
The maven project uses logback:
Add to pom file:
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.1.5</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.5</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-access</artifactId>
<version>1.1.5</version>
</dependency>
Components can also be added manually:
logback-access-1.1.5.jar
logback-classic-1.1.5.jar
logback-core-1.1.5.jar
slf4j-api-1.7.16.jar
Note: If you use open source frameworks such as struts, spring, hibernate, etc. in combination with frameworks, many of these frameworks use log4j to record logs, so log4j-over-slf4j-1.6.6.jar is required
2. Start using
1. Use logback to print the log to the console:
Sample code:
/**
* @author zw Date: 2016/10/9 Time:15:04.
*/
public class TestDemo {
private static Logger log = LoggerFactory.getLogger(TestDemo.class);
public static void main(String[]args){
/**
* The log log is divided into five levels of trace debug info warn error
* level rank order trace < debug < info < warn < error
*/
log.trace("----this log is trace level");
log.debug("----this log is debug level");
log.info("----this log is info level");
log.warn("----this log is warn level");
log.error("----this log is error level");
String name = "logback";
String message = "demo";
String[] params = { "logback", "logback" };
// The printing method provided by logback that can use variables
log.info("##########hello,{}!", name);
// Use placeholders to output log information
log.info("##########hello {}! this is {}!", name, message);
// can pass an array
log.info("##########hello {}! this is {}", params);
}
}
logback.xml configuration file
<?xml version="1.0" encoding="UTF-8"?>
<!--configuration attribute description:
scan attribute: used to set whether to reload when the configuration file changes, the value is true\false, the default is true, that is, reload when the configuration changes
scanPeriod attribute: used to set how often to check whether the configuration changes, the default is 1 minute, the default unit is milliseconds
debug attribute: used to set whether to print out the internal log of logback, that is, output configuration loading information at startup. The value is true\false and the default is false-->
<configuration scan="true" scanPeriod="60 seconds" debug="false">
<!--Define log output format-->
<property name="enPattern" value="%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n" />
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder >
<pattern>${enPattern}</pattern>
</encoder>
</appender>
<!-- The default level of root is DEBUG and can contain multiple <appender-ref> elements -->
<root level="TRACE">
<appender-ref ref="STDOUT" />
</root>
</configuration>
2. Record the log to a file:
Sample code: Same as the sample code in 1.
logback configuration file modification:
In configuration add:
<!--Define log output file directory--> <property name="outFilePath" value="E:/个人/demo/logs/demo.log" />
and replace the appender node,
<appender name="STDOUT" class="ch.qos.logback.core.FileAppender">
<file>${outFilePath}</file>
<append>true</append>
<encoder charset="UTF-8">
<pattern>${enPattern}</pattern>
</encoder>
</appender>
3. Output to file and console at the same time:
The sample code is the same as 1.
The configuration file is as follows:
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder charset="UTF-8">
<pattern>${enPattern}</pattern>
</encoder>
</appender>
<appender name="toFile" class="ch.qos.logback.core.FileAppender">
<file>${outFilePath}</file>
<append>true</append>
<encoder charset="UTF-8">
<pattern>${enPattern}</pattern>
</encoder>
</appender>
<!-- The default level of root is DEBUG and can contain multiple <appender-ref> elements -->
<root level="debug">
<appender-ref ref="STDOUT" />
<appender-ref ref="toFile" />
</root>
4. Output the log to a file and wait for a file every day or every hour:
Sample code: same as 1:
Configuration file:
On the basis of 3, modify. Increase:
<!--Define the log output file before today-->
<property name="outOldFilePath" value="E:/个人/demo/logs/demo-%d{yyyy-MM-dd}.log" />
And modify the appender whose name is toFile, after modification as follows:
<!--Define log output format-->
<property name="enPattern" value="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level {%C.java:%L} - %msg%n" />
<!--Define log output file directory-->
<property name="outFilePath" value="E:/个人/demo/logs/demo.log" />
<!--Define the log output file before today-->
<property name="outOldFilePath" value="E:/个人/demo/logs/demo-%d{yyyy-MM-dd}.log" />
<!--Configuration with loger, do not specify level, do not specify appender output to console -->
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder charset="UTF-8">
<pattern>${enPattern}</pattern>
</encoder>
</appender>
<!--Today's log is output to outFilePath, and the log before today is in -->
<appender name="toFile" class="ch.qos.logback.core.rolling.RollingFileAppender">
<!--Log file for today's log records-->
<file>${outFilePath}</file>
<append>true</append>
<!--Set yesterday's log file-->
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!--The log file of yesterday's log-->
<fileNamePattern>${outOldFilePath}</fileNamePattern>
<!--Keep logs for 30 days-->
<maxHistory>30</maxHistory>
</rollingPolicy>
<encoder charset="UTF-8">
<pattern>${enPattern}</pattern>
</encoder>
</appender>
<!-- The default level of root is DEBUG and can contain multiple <appender-ref> elements -->
<root level="debug">
<appender-ref ref="STDOUT" />
<appender-ref ref="toFile" />
</root>
You can also output files by minutes or hours, adjust
<property name="outOldFilePath" value="E:/个人/demo/logs/demo-%d{yyyy-MM-dd}.log" />
for:
a. By hour:
<property name="outOldFilePath" value="E:/个人/demo/logs/demo-%d{yyyyMMddHH}.log" />
b. In minutes:
<property name="outOldFilePath" value="E:/个人/demo/logs/demo-%d{yyyyMMddHHMM}.log" />
Please correct me if I misunderstand, thank you