JavaEE 添加简单的日志过滤器

<!-- 日志过滤器-->
<filter>
<filter-name>logFilter</filter-name>
<filter-class>chapter9.RequestLogFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>logFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

package chapter9;

import org.apache.commons.lang3.time.StopWatch;

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.HttpServletResponse;
import java.io.IOException;
import java.time.Instant;

/**
* 日志过滤器
*/
public class RequestLogFilter implements Filter
{
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException
{
Instant time = Instant.now();
StopWatch timer = new StopWatch();
try
{
timer.start();
chain.doFilter(request, response);
}
finally
{
timer.stop();
HttpServletRequest in = (HttpServletRequest)request;
HttpServletResponse out = (HttpServletResponse)response;
String length = out.getHeader("Content-Length");
if(length == null || length.length() == 0)
length = "-";
System.out.println(in.getRemoteAddr() + " - - [" + time + "]" +
" \"" + in.getMethod() + " " + in.getRequestURI() + " " +
in.getProtocol() + "\" " + out.getStatus() + " " + length +
" " + timer);
}
}

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

@Override
public void destroy() { }
}