log4j2 常见配置并支持logId

声明：原创文章，转载请注明出处。http://www.jianshu.com/u/e02df63eaa87

1、常见配置及解释

<?xml version="1.0" encoding="UTF-8"?>
<!--日志级别以及优先级排序: OFF > FATAL > ERROR > WARN > INFO > DEBUG > TRACE > ALL -->
<!--Configuration后面的status，这个用于设置log4j2自身内部的信息输出，可以不设置，当设置成trace时，你会看到log4j2内部各种详细输出-->
<!--monitorInterval：Log4j能够自动检测修改配置 文件和重新配置本身，设置间隔秒数-->
<configuration status="INFO" monitorInterval="30">
    <!--先定义所有的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="[ %p ] [%-d{yyyy-MM-dd HH:mm:ss}] [ LOGID:%X{logid} ] [%l] %m%n"/>
        </console>

        <!--文件会打印出所有信息，这个log每次运行程序会自动清空，由append属性决定，这个也挺有用的，适合临时测试用-->
        <File name="Test" fileName="log/test.log" append="false">
            <PatternLayout pattern="[ %p ] %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] [%l] %m%n"/>
        </File>

        <RollingFile name="RollingFileInfo" fileName="log/log.log" filePattern="log/log.log.%d{yyyy-MM-dd}">
            <!-- 只接受level=INFO以上的日志 -->
            <ThresholdFilter level="info" onMatch="ACCEPT" onMismatch="DENY"/>
            <PatternLayout pattern="[ %p ] [%-d{yyyy-MM-dd HH:mm:ss}] [ LOGID:%X{logid} ] [%l] %m%n"/>
            <Policies>
                <TimeBasedTriggeringPolicy modulate="true" interval="1"/>
                <SizeBasedTriggeringPolicy/>
            </Policies>
        </RollingFile>

        <RollingFile name="RollingFileError" fileName="log/error.log" filePattern="log/error.log.%d{yyyy-MM-dd}">
            <!-- 只接受level=WARN以上的日志 -->
            <Filters>
            <ThresholdFilter level="warn" onMatch="ACCEPT" onMismatch="DENY" />
            </Filters>
            <PatternLayout pattern="[ %p ] %-d{yyyy-MM-dd HH:mm:ss} [ %t:%r ] [%l] %m%n"/>
            <Policies>
                <TimeBasedTriggeringPolicy modulate="true" interval="1"/>
                <SizeBasedTriggeringPolicy/>
            </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="Test"/>
            <appender-ref ref="RollingFileInfo"/>
            <appender-ref ref="RollingFileError"/>
        </root>
    </loggers>
</configuration>

2、Java端配置

运行时指定上述log4j2.xml的配置：

-Dlog4j.configurationFile=./conf/log4j2.xml

3、输出logId或者与log交互

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.ThreadContext;

/**
 * Created by think on 2017/1/22 0022.
 */
public class LogTest {
    private static final Logger logger = LogManager.getLogger(LogTest.class);

    static class test extends Thread {
        @Override
        public void run() {
            long time = System.currentTimeMillis();
            ThreadContext.put("logid", String.valueOf( time));
            logger.info("test thread.");
            ThreadContext.clearAll();
        }
    }

    public static void main(String[] args) {
        long time = System.currentTimeMillis() ;
        ThreadContext.put("logid", String.valueOf(time));
        try {
            logger.trace("trace...");
            logger.debug("debug...");
            logger.info("info...");
            logger.warn("warn...");
            logger.error("error...");
            logger.fatal("fatal...");

            test test1 = new test();
            test test2 = new test();
            test1.start();
            test2.start();

        } catch (Exception e) {
            e.printStackTrace();
        }

        ThreadContext.clearAll();
    }
}

输出：

[ TRACE ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:37)] trace...
[ DEBUG ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:38)] debug...
[ INFO ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:39)] info...
[ WARN ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:40)] warn...
[ ERROR ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:41)] error...
[ FATAL ] [2017-02-04 17:10:27] [ LOGID:199427158 ] [logtest.LogTest.main(LogTest.java:42)] fatal...
[ INFO ] [2017-02-04 17:11:38] [ LOGID:199498552 ] [logtest.LogTest$test.run(LogTest.java:20)] test thread.
[ INFO ] [2017-02-04 17:11:38] [ LOGID:199498551 ] [logtest.LogTest$test.run(LogTest.java:20)] test thread.

本文代码可参考：https://github.com/hawkingfoo/log-test