1\了解过滤器的声明周期

2\过滤器的web.xml文件的配置

 <filter>

	  <filter-name>EncodingFilter</filter-name>

	  <filter-class>com.gyarmy.demo1.EncodingFilter</filter-class>

	  <init-param>

	  	<param-name>encoding</param-name>

	  	<param-value>utf-8</param-value>

	  </init-param>

  </filter>

  

  <filter-mapping>

  	<filter-name>EncodingFilter</filter-name>

  	<url-pattern>/*</url-pattern>

  </filter-mapping>

3\过滤器的使用

package com.gyarmy.demo1;



import java.io.IOException;



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;



public class EncodingFilter implements Filter {



	private FilterConfig config;



	@Override

	public void destroy() {

		// TODO Auto-generated method stub



	}



	@Override

	public void doFilter(ServletRequest req, ServletResponse resp,

			FilterChain chain) throws IOException, ServletException {

		// TODO Auto-generated method stub

		//方便滴啊用API

		HttpServletRequest request =  (HttpServletRequest)req;

		HttpServletResponse response = (HttpServletResponse)resp;

		

		//设置编码

		String encoding = config.getInitParameter("encoding");

		System.out.println(encoding);

		response.setContentType("text/html;charset="+encoding);

		

		//禁止缓存数据

		response.setHeader("cache-control", "no-cache");

		response.setHeader("pragma", "no-cache");

		response.setDateHeader("expires", 0);

		

		

		chain.doFilter(request, response);

		

		

	}



	@Override

	public void init(FilterConfig filterConfig) throws ServletException {

		// TODO Auto-generated method stub

		this.config = filterConfig;

	}



}