log4j2配置固定内容(IP等)

需求： 记录日志时需要添加服务IP和服务编号(由UUID生成)，便于运维人员在查看日志时定位到哪台服务器上的哪个服务。

基于spring web项目

1、 log4j2.xml文件

<?xml version="1.0" encoding="UTF-8"?><Configuration status="error" monitorInterval="30">    <Properties>        <!-- 配置日志文件输出目录 -->        <Property name="LOG_HOME">/home/logs</Property>    </Properties>    <Appenders>        <Console name="CONSOLE" target="SYSTEM_OUT">            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level %class{1.}:%L - IP:%X{ip}&amp;ID:%X{UUID}  %msg%xEx%n" />        </Console>        <!-- 按天第天备份一个日志 -->        <RollingFile name="FILE" fileName="${LOG_HOME}/demo.log"            filePattern="${LOG_HOME}/demo.log.%d{yyyy-MM-dd}.log.gz">            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} %-5level %class{1.}:%L - %X{ip}&amp;ID:%X{UUID}  %msg%xEx%n" />            <Policies>                <!-- 每24小时更新一次 -->                <TimeBasedTriggeringPolicy modulate="true"                    interval="24" />                <SizeBasedTriggeringPolicy size="128KB" />            </Policies>            <!-- 最多备份10个 -->            <DefaultRolloverStrategy max="10" />        </RollingFile>    </Appenders>    <Loggers>        <!--<Logger name="com.mosen" level="info">-->            <!--<AppenderRef ref="FILE" />-->        <!--</Logger>-->        <Root level="info">            <AppenderRef ref="CONSOLE" />            <AppenderRef ref="FILE"></AppenderRef>        </Root>    </Loggers></Configuration>

pattern格式配置
%d{yyyy-MM-dd HH:mm:ss.SSS} “d”, “date” 时间格式
%-5level “p”, “level” 输出日志级别，-5表示左对齐并且固定输出5个字符，如果不足在右边补0
%class{1.} “C”, “class” 类名，包名只有1位
%C{3} 获取类名前3级目录(包含类名)
%L “L”, “line” 输出行号
%M “M”, “method” 输出所在方法名
%m “m”, “msg”, “message” 日志文本
%xEx “xEx”, “xThrowable”, “xException” ExtendedThrowablePatternConverter
“ex”, “throwable”, “exception” ThrowablePatternConverter
“rEx”, “rThrowable”, “rException” RootThrowablePatternConverter
%n 换行

其他占位符有(部分)：
%l “l”, “location” 输出语句所在的行数, 包括类名、方法名、文件名、行数 例如：hahaha.Log4j2Test.main(Log4j2Test.java:15)
%T “T”, “tid”, “threadId” 输出线程ID
%t “t”, “tn”, “thread”, “threadName” 输出当前线程名称
%tp “tp”, “threadPriority” 输出线程权级
%F “F”, “file” 输出所在的类文件名，如Log4j2Test.java
%logger “c”, “logger” 输出logger名称，LogManager.getLogger(Log4j2Test.class);中的名称，此处是hahaha.Log4j2Test
%N “N”, “nano” 纳秒
%sn “sn”, “sequenceNumber” 日志计数(全局)
%u “u”, “uuid” UUID(全局)
%X{ip} “X”, “mdc”, “MDC” MDC方式获取ip(等同于 %MDC{ip} 和 %mdc{ip} )
%x “x”, “NDC” NDC方式

2、 过滤器类
log4j2中用ThreadContext代替MDC

package demo;import org.apache.logging.log4j.ThreadContext;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import java.io.IOException;public class ThreadContextFilter implements Filter {    @Override    public void init(FilterConfig filterConfig) throws ServletException {    }    @Override    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {        try {            ThreadContext.put("UUID", StaticUUID.ID);    //StaticUUID是自己写的类，用于生成UUID常量。            ThreadContext.put("ip", request.getLocalAddr());            chain.doFilter(request, response);        } finally {        //清除ThreadContext,避免内存泄露            ThreadContext.clearAll();        }    }    @Override    public void destroy() {    }}

3、 web.xml

<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd" ><web-app>    <display-name>Archetype Created Web Application</display-name>    <filter>        <filter-name>log4jFilter</filter-name>        <filter-class>demo.ThreadContextFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>log4jFilter</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>    <servlet>        <servlet-name>log4j2demo</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:applicationContext.xml</param-value>        </init-param>        <load-on-startup>1</load-on-startup>    </servlet>    <servlet-mapping>        <servlet-name>log4j2demo</servlet-name>        <url-pattern>/</url-pattern>    </servlet-mapping>    <welcome-file-list>        <welcome-file>index.html</welcome-file>        <welcome-file>index.htm</welcome-file>        <welcome-file>index.jsp</welcome-file>        <welcome-file>default.html</welcome-file>        <welcome-file>default.htm</welcome-file>        <welcome-file>default.jsp</welcome-file>    </welcome-file-list></web-app>

4、 Hello类测试

package demo;import org.apache.logging.log4j.LogManager;import org.apache.logging.log4j.Logger;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;@Controllerpublic class Hello {    public static Logger logger = LogManager.getLogger();    @RequestMapping("/hello")    public void hello(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        logger.info("hello");        request.getRequestDispatcher("index.jsp").forward(request, response);    }}

测试结果(多次刷新页面)
2017-06-28 21:04:59.013 INFO d.Hello:22 - IP:0:0:0:0:0:0:0:1&trace ID:5ba23654bc104e8b8019963084f16cb8 hello

2017-06-28 21:06:48.364 INFO d.Hello:22 - IP:0:0:0:0:0:0:0:1&trace ID:5ba23654bc104e8b8019963084f16cb8 hello

2017-06-28 21:06:49.203 INFO d.Hello:22 - IP:0:0:0:0:0:0:0:1&trace ID:5ba23654bc104e8b8019963084f16cb8 hello

2017-06-28 21:06:49.900 INFO d.Hello:22 - IP:0:0:0:0:0:0:0:1&trace ID:5ba23654bc104e8b8019963084f16cb8 hello
其中IP:0:0:0:0:0:0:0:1等同于127.0.0.1，由于是本地访问，就会出现这个值。用别的机器访问就会正常。