<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
        prefix="localhost_access_log." suffix=".txt"
        pattern="%h %l %u %t &quot;%r&quot; [%{postdata}r] %s %{Referer}i %{User-Agent}i %T %b" />

%a  这是记录访问者的IP，在日志里是127.0.0.1 
%A  这是记录本地服务器的IP，在日志里是192.168.254.108 
%b  发送信息的字节数，不包括http头，如果字节数为0的话，显示为- 
%B  发送信息的字节数，不包括http头。 
%h  服务器的名称。如果resolveHosts为false的话，这里就是IP地址了，例如我的日志里是10.217.14.16 
%H  访问者的协议，这里是HTTP/1.0 
%l  官方解释：Remote logical username from identd (可能这样翻译：记录浏览者进行身份验证时提供的名字)(always returns '-') 
%m  访问的方式，是GET还是POST 
%p  本地接收访问的端口  
%q  比如你访问的是aaa.jsp"-" 
%U  访问的URL地址，我这里是/rightmainima/leftbott4.swf 
%v  服务器名称，可能就是你url里面写的那个吧，我这里是localhost 
%D  Time taken to process the request,in millis，请求消耗的时间，以毫秒记 
%T  Time taken to process the request,in seconds，请求消耗的时间，以秒记 

package com.xiaoxiliu  
import java.io.IOException; 
import java.util.Enumeration;  
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 org.slf4j.Logger; 
import org.slf4j.LoggerFactory;  
public final class PostDataDumperFilter implements Filter {  
  Logger logger = LoggerFactory.getLogger(getClass());  
  private FilterConfig filterConfig = null;  
  public void destroy() { 
    this.filterConfig = null; 
  } 
 
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
      throws IOException, ServletException { 
    if (filterConfig == null) 
      return;  
    Enumeration<String> names = request.getParameterNames(); 
    StringBuilder output = new StringBuilder(); 
    while (names.hasMoreElements()) { 
      String name = (String) names.nextElement(); 
      output.append(name).append("="); 
      String values[] = request.getParameterValues(name); 
      for (int i = 0; i < values.length; i++) { 
        if (i > 0) { 
          output.append("' "); 
        } 
 
        output.append(values[i]); 
      } 
      if (names.hasMoreElements()) 
        output.append("&"); 
    } 
    request.setAttribute("postdata", output); 
    logger.debug("postdata: " + output); 
    chain.doFilter(request, response); 
  } 
 
  public void init(FilterConfig filterConfig) throws ServletException { 
    this.filterConfig = filterConfig; 
  } 
} 

<filter> 
    <filter-name>post-data-dumper-filter</filter-name> 
    <filter-class>com.xiaoxiliu.PostDataDumperFilter</filter-class> 
  </filter> 
  <filter-mapping> 
    <filter-name>post-data-dumper-filter</filter-name> 
    <url-pattern>/*</url-pattern> 
  </filter-mapping>