session共享

矫情吗；* 2022-05-21 12:51 193阅读 0赞

思路：就是模拟一个session，利用redis，redis可以设置过期时间。这样就不局限在一个tomcat里了。在用户登陆成功后，用uuid生成一个字符串，相当于sessionid作为key，用户的'User'对象作为value存储在redis里然后吧这个sessionid写入cookie中就行了。

这里有个cookie工具类分享一下：

package com.utils;
    
    import java.io.UnsupportedEncodingException;
    import java.net.URLDecoder;
    import java.net.URLEncoder;
    
    import javax.servlet.http.Cookie;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    
    /**
     * 
     * 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
         */
        private static final String getDomainName(HttpServletRequest request) {
            String domainName = null;
    
            String serverName = request.getRequestURL().toString();
            if (serverName == null || serverName.equals("")) {
                domainName = "";
            } else {
                serverName = serverName.toLowerCase();
                serverName = serverName.substring(7);
                final int end = serverName.indexOf("/");
                serverName = serverName.substring(0, end);
                final String[] domains = serverName.split("\\.");
                int len = domains.length;
                if (len > 3) {
                    // www.xxx.com.cn
                    domainName = "." + domains[len - 3] + "." + domains[len - 2] + "." + domains[len - 1];
                } else if (len <= 3 && len > 1) {
                    // xxx.com or xxx.cn
                    domainName = "." + domains[len - 2] + "." + domains[len - 1];
                } else {
                    domainName = serverName;
                }
            }
    
            if (domainName != null && domainName.indexOf(":") > 0) {
                String[] ary = domainName.split("\\:");
                domainName = ary[0];
            }
            return domainName;
        }
    
    }