利用cookie作为保存信息，需要做处理的是获取domain，特别是跨域问题，不同的网址域名不一样，

package com.rb.utils.auth;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.UnsupportedEncodingException;import java.net.URLDecoder;import java.net.URLEncoder;/** *  * Cookie 工具类 * */public final class CookieUtils {    /**     * 得到Cookie的值, 不编码     *      * @param request     * @param cookieName     * @return     */    public static String getCookieValue(HttpServletRequest request, String cookieName) {        return getCookieValue(request, cookieName, false);    }    /**     * 得到Cookie的值,     *      * @param request     * @param cookieName     * @return     */    public static String getCookieValue(HttpServletRequest request, String cookieName, boolean isDecoder) {        Cookie[] cookieList = request.getCookies();        if (cookieList == null || cookieName == null) {            return null;        }        String retValue = null;        try {            for (int i = 0; i < cookieList.length; i++) {                if (cookieList[i].getName().equals(cookieName)) {                    if (isDecoder) {                        retValue = URLDecoder.decode(cookieList[i].getValue(), "UTF-8");                    } else {                        retValue = cookieList[i].getValue();                    }                    break;                }            }        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        return retValue;    }    /**     * 得到Cookie的值,     *      * @param request     * @param cookieName     * @return     */    public static String getCookieValue(HttpServletRequest request, String cookieName, String encodeString) {        Cookie[] cookieList = request.getCookies();        if (cookieList == null || cookieName == null) {            return null;        }        String retValue = null;        try {            for (int i = 0; i < cookieList.length; i++) {                if (cookieList[i].getName().equals(cookieName)) {                    retValue = URLDecoder.decode(cookieList[i].getValue(), encodeString);                    break;                }            }        } catch (UnsupportedEncodingException e) {             e.printStackTrace();        }        return retValue;    }    /**     * 设置Cookie的值 不设置生效时间默认浏览器关闭即失效,也不编码     */    public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,            String cookieValue) {        setCookie(request, response, cookieName, cookieValue, -1);    }    /**     * 设置Cookie的值 在指定时间内生效,但不编码     */    public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,            String cookieValue, int cookieMaxage) {        setCookie(request, response, cookieName, cookieValue, cookieMaxage, false);    }    /**     * 设置Cookie的值 不设置生效时间,但编码     */    public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,            String cookieValue, boolean isEncode) {        setCookie(request, response, cookieName, cookieValue, -1, isEncode);    }    /**     * 设置Cookie的值 在指定时间内生效, 编码参数     */    public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,            String cookieValue, int cookieMaxage, boolean isEncode) {        doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, isEncode);    }    /**     * 设置Cookie的值 在指定时间内生效, 编码参数(指定编码)     */    public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,            String cookieValue, int cookieMaxage, String encodeString) {        doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, encodeString);    }    /**     * 删除Cookie带cookie域名     */    public static void deleteCookie(HttpServletRequest request, HttpServletResponse response,            String cookieName) {        doSetCookie(request, response, cookieName, "", -1, false);    }    /**     * 设置Cookie的值，并使其在指定时间内生效     *      * @param cookieMaxage cookie生效的最大秒数     */    private static final void doSetCookie(HttpServletRequest request, HttpServletResponse response,            String cookieName, String cookieValue, int cookieMaxage, boolean isEncode) {        try {            if (cookieValue == null) {                cookieValue = "";            } else if (isEncode) {                cookieValue = URLEncoder.encode(cookieValue, "utf-8");            }            Cookie cookie = new Cookie(cookieName, cookieValue);            if (cookieMaxage > 0)                cookie.setMaxAge(cookieMaxage);            if (null != request) {
    // 设置域名的cookie                String domainName = getDomainName(request);                System.out.println(domainName);                if (!"localhost".equals(domainName)) {                    cookie.setDomain(domainName);                }            }            cookie.setPath("/");            response.addCookie(cookie);        } catch (Exception e) {             e.printStackTrace();        }    }    /**     * 设置Cookie的值，并使其在指定时间内生效     *      * @param cookieMaxage cookie生效的最大秒数     */    private static final void doSetCookie(HttpServletRequest request, HttpServletResponse response,            String cookieName, String cookieValue, int cookieMaxage, String encodeString) {        try {            if (cookieValue == null) {                cookieValue = "";            } else {                cookieValue = URLEncoder.encode(cookieValue, encodeString);            }            Cookie cookie = new Cookie(cookieName, cookieValue);            if (cookieMaxage > 0)                cookie.setMaxAge(cookieMaxage);            if (null != request) {
    // 设置域名的cookie                String domainName = getDomainName(request);                System.out.println(domainName);                if (!"localhost".equals(domainName)) {                    cookie.setDomain(domainName);                }            }            cookie.setPath("/");            response.addCookie(cookie);        } catch (Exception e) {             e.printStackTrace();        }    }    /**     * 得到cookie的域名     */    public static final String getDomainName(HttpServletRequest request) {        String url = request.getRequestURL().toString();        String result = "";        int j = 0, startIndex = 0, endIndex = 0;        for (int i = 0; i < url.length(); i++) {            if (url.charAt(i) == '/') {                j++;                if (j == 2)                    startIndex = i;                else if (j == 3)                    endIndex = i;            }        }        result = url.substring(startIndex + 1, endIndex);        if (result != null && result.indexOf(":") > 0) {            String[] ary = result.split("\\:");            result = ary[0];        }        return result;    }}

 

根据请求动态获取域名。