httpfilter.java

这段代码是用struts实现的客户管理系统

package com.tarena.util;

import java.io.IOException;

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

/**
 * 基于HTTP协议的通用过滤器的实现。设计该类的目的
 * 是让开发者通过继承该类来编写过滤器，从而使开发者
 * 关注的是HTTP协议下的request, response
 * 提供了安全的init方法供子类覆盖
 * 提供了方便的读取初始化参数的方法
 * 提供了方便的获取上下文对象的方法
 * 
 * @author Allan
 */
public abstract class HttpFilter implements Filter {
	private FilterConfig config;

	public void init(FilterConfig config) throws ServletException {
		this.config = config;
		init();
	}

	public void init() throws ServletException {
	}
	
	public ServletContext getServletContext(){
		return config.getServletContext();
	}

	public String getInitParameter(String name) {
		return config.getInitParameter(name);
	}

	public final void doFilter(ServletRequest request,
			ServletResponse response, FilterChain chain) throws IOException,
			ServletException {
		doFilter((HttpServletRequest) request, (HttpServletResponse) response,
				chain);
	}

	public abstract void doFilter(HttpServletRequest request,
			HttpServletResponse response, FilterChain chain)
			throws IOException, ServletException;

	public void destroy() {
	}
}