使用log4j的时候如何输出printStackTrace()的堆栈信息 

研究了一下发现很简单，如下： 
log.error(e.getMessage(),e); 

输出信息如下： 
2009-05-11 12:40:45  [ Thread-1:2231687 ] - [ ERROR ]  Connection reset by peer: socket write error 
java.net.SocketException: Connection reset by peer: socket write error 
at java.net.SocketOutputStream.socketWrite0(Native Method) 
at java.net.SocketOutputStream.socketWrite(Unknown Source) 
at java.net.SocketOutputStream.write(Unknown Source) 
at java.io.DataOutputStream.write(Unknown Source) 
at java.io.FilterOutputStream.write(Unknown Source) 
at com.mythlink.facebook.server.Server.run(Server.java:110) 
at java.lang.Thread.run(Unknown Source) 

其中Connection reset by peer: socket write error 是e.getMessage();所得到的