Filter的例子

package com.test.filter;



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;

public class Demo1Filter implements Filter {

private FilterConfig filterConfig;



public void doFilter(ServletRequest request, ServletResponse response,

FilterChain chain) throws IOException, ServletException {

System.out.println("Demo1过滤前");

System.out.println(filterConfig.getInitParameter("param1"));

chain.doFilter(request, response);//放行。让其走到下个链或目标资源中

System.out.println("Demo1过滤后");

}



public void init(FilterConfig filterConfig) throws ServletException {

System.out.println("初始化了");

this.filterConfig = filterConfig;

}



public void destroy() {

System.out.println("销毁了");

}

}