log4j记录前端用户登陆信息 .
原文地址：http://blog.donews.com/ooFrank/archive/2006/02/11/722553.aspx
在记录日志的时候，我们可能有这种需求，对于每个记录除了知道日志信息外，也要当前登录用户的信息。
可以这样解决：使用log4j的MDC
在web.xml加入 Filter：
<filter>
? <filter-name>set log4j MDC for log2userId</filter-name>
? <filter-class>UserFilter</filter-class>
? </filter>
? <filter-mapping>
? <filter-name>set log4j MDC for log2userId</filter-name>
? <url-pattern>/*</url-pattern>
? </filter-mapping>
UserFilter的代码如下：
import org.apache.log4j.Logger;
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 javax.servlet.http.HttpSession;
import org.apache.log4j.MDC;
import org.springside.bookstore.domain.Customer;
/**
?* 记录当前使用者的信息到log4j.MDC
?* @author frank
?*
?*/
public class UserFilter implements Filter {
?? ?/**
?? ? * Logger for this class
?? ? */
?? ?private static final Logger logger = Logger.getLogger(UserFilter.class);
??? private final static String DEFAULT_USERID="anonymous";
?
?? ?public void doFilter(ServletRequest request, ServletResponse response,
?? ??? ??? ?FilterChain chain) throws IOException, ServletException {
?? ??? ?HttpServletRequest req=(HttpServletRequest)request;
?? ??? ?HttpSession session= req.getSession();
?? ??? ?if (session==null){
?? ??? ??? ?MDC.put("userId",DEFAULT_USERID); ?
?? ??? ?}
?? ??? ?else{
?? ??? ??? ?Customer customer=(Customer)session.getAttribute("customer");
?? ??? ??? ?if (customer==null){
?? ??? ??? ??? ?MDC.put("userId",DEFAULT_USERID);
?? ??? ??? ?}
?? ??? ??? ?else
?? ??? ??? ?{
?? ??? ??? ??? ?MDC.put("userId",customer.getLoginid());
?? ??? ??? ?}
?? ??? ?}
?? ??? ?logger.info("test for MDC.");
?? ??? ?
?? ??? ?chain.doFilter(request,response);
?? ?}
?? ?public void init(FilterConfig fc) throws ServletException {
?? ??? ?
?? ??? ?// do nothing
?? ??? ?
?? ?}
?? ?public void destroy() {
//?? ??? ? do nothing
?? ?}
}
在log4j.properties中加入新配置，示例使用jdbc存储
log4j.appender.db=org.apache.log4j.jdbc.JDBCAppender
#log4j.appender.db.BufferSize=100
log4j.appender.db.URL=jdbc:ulr
log4j.appender.db.driver=org.hsqldb.jdbcDriver
log4j.appender.db.user=sa
log4j.appender.db.password=
log4j.appender.db.sql=INSERT INTO LOG4J_MSG (LOGINID,PRIORITY,LOGDATE,CLASS,METHOD,MSG) VALUES('%X{userId}','%p','%d{yyyy-MM-dd HH:mm:ss}','%C','%M','%m')
%X{userId}：就是取出MDC的代码了
