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>
public class UserFilter implements Filter {
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