log4j显示ip或用户名等自定义信息

通过过滤器来实现web应用的log4j打印自定义信息

import java.io.IOException;

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 javax.servlet.http.HttpServletRequest;

import org.apache.log4j.MDC;

public class Log4jFilter implements Filter{
	@Override
	public void doFilter(ServletRequest req, ServletResponse res,FilterChain chain) throws IOException, ServletException {
		String ip = req.getRemoteAddr();
		String userName = (String)((HttpServletRequest)req).getSession().getAttribute("userName");//获取用户名
		MDC.put("ip", ip);
		MDC.put("userName", userName);
		chain.doFilter(req, res);
		MDC.remove("ip");
		MDC.remove("userName");
	}

	@Override
	public void init(FilterConfig arg0) throws ServletException {
	}
	@Override
	public void destroy() {
	}
}

log4j配置文件

log4j.rootCategory=debug, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d{HH:mm:ss.SSS}] %p %X{ip} %X{userName} %c{1}.%M(%L) | %m%n

[15:27:52.682] DEBUG 127.0.0.1 admin SimpleTest.testLog(42) | testLog