logfilter.java

一个用JAVA编写的过滤器,有各种功能,打开看看就知道了

/*******************************************************************
<br>Copyright (C), 2005-2008, yeeku.H.Lee
<br>Program Name:
<br>Author:yeeku.H.lee [e-mail]
<br>Version:1.0
<br>This program is protected by copyright laws.
<br>Date: 
*******************************************************************/

package lee;


import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.FilterChain;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletContext;

public class LogFilter implements Filter 
{
    private FilterConfig config; 
    
    public void init(FilterConfig config)
    { 
        this.config = config; 
    }

    public void destroy()
    { 
        this.config = null; 
    }

    public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain)
    {
        try
        {
            request.setCharacterEncoding("GBK");       	
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        
        ServletContext context = this.config.getServletContext(); 
        
        long before = System.currentTimeMillis();
        System.out.println("开始过滤...");
        HttpServletRequest hrequest = (HttpServletRequest)request;
        context.log("Filter已经截获到用户的请求的地址： " + hrequest.getServletPath());
        try
        {
            //为请求“放行”
            chain.doFilter(request, response); //此处不需要链参数 
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        long after = System.currentTimeMillis();
        System.out.println("过滤结束");
        context.log("请求被定位到" + ((HttpServletRequest)request).getRequestURI() + "   所花的时间为: " + (after - before)); 
    } 
}