JavaWeb 过滤器 Filter 的配置使用（相关知识点：重定向，Ajax请求和普通请求判断）

1.在web.xml中配置filter过滤器

<filter>
		<filter-name>cookieFilter</filter-name>
		<filter-class>com.xxx.commonsys.interceptor.CookieFilter</filter-class>
</filter>

<filter-mapping>
		<filter-name>cookieFilter</filter-name>
		<url-pattern>/*</url-pattern>
</filter-mapping>

2.CookieFilter.java文件内容

/*
 * CookieFilter.java Created On 2015-8-12
 * Copyright(c) 2014 BroadText Inc.
 * ALL Rights Reserved.
 */
package com.xxx.commonsys.interceptor;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

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.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * CookieFilter
 * 
 * @time: 下午2:56:51
 * @author xxx
 */
public class CookieFilter implements Filter {
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse resp = (HttpServletResponse) response;

        //cookieFilter
		Cookie[] cookies = req.getCookies();
		
		//应用程序未容错漏洞修复 2016-08-30 xxx begin
		String url = req.getRequestURI();
		//*****判断异步请求和普遍请求*****
		String if_flag = req.getHeader("X-Requested-With");
		//不是ajax请求
		if (if_flag == null) {
		    if ("/itos/bfapp/buffalo/cpMainServiceAjax".equals(url) ||
	                "/itos/bfapp/buffalo/dmMainServiceAjax".equals(url)) {
				//*****重定向*****
	            resp.sendRedirect(req.getContextPath()+"/pages/common/500.jsp");
	            return;
	        }
		}
		//应用程序未容错漏洞修复 2016-08-30 xxx end
		
		if (cookies != null) {
			Cookie cookie = cookies[0];
			if (cookie != null) {
				/*
				 * cookie.setMaxAge(3600);
				 * cookie.setSecure(true);
				 * resp.addCookie(cookie);
				 */

				// Servlet 2.5不支持在Cookie上直接设置HttpOnly属性
				String value = cookie.getValue();
				StringBuilder builder = new StringBuilder();
				builder.append("JSESSIONID=" + value + "; ");
				builder.append("Secure; ");
				builder.append("HttpOnly; ");
				Calendar cal = Calendar.getInstance();
				cal.add(Calendar.HOUR, 1);
				Date date = cal.getTime();
				Locale locale = Locale.US;
				SimpleDateFormat sdf = new SimpleDateFormat(
						"dd-MM-yyyy HH:mm:ss", locale);
				builder.append("Expires=" + sdf.format(date));
				resp.setHeader("Set-Cookie", builder.toString());
			}
		}
	}

	public void destroy() {
	}

	public void init(FilterConfig arg0) throws ServletException {
	}

}