1.近期在弄shiro的安全框架，目前情况是后端使用form请求进行登录，前端使用ajax进行登录。一是为减少重复代码编写，二是为了深入了解shiro的一些知识。

2.后端框架使用ssm + shiro1.2.3，缓存方面主要用ehcache2.6.11或者redis，主要的shiro pom依赖有如下：

 <properties>
            <shiro.version>1.2.3</shiro.version>
 </properties>
<dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-core</artifactId>
            <version>${shiro.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-spring</artifactId>
            <version>${shiro.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-cas</artifactId>
            <version>${shiro.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>commons-logging</groupId>
                    <artifactId>commons-logging</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-web</artifactId>
            <version>${shiro.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-ehcache</artifactId>
            <version>${shiro.version}</version>
        </dependency>

3.spring配置shiro

<!-- Shiro权限过滤过滤器定义 -->
    <bean name="shiroFilterChainDefinitions" class="java.lang.String">
        <constructor-arg>
            <value>
                /open/smartFactory/** = authc
                /weixin/** = anon
                /static/** = anon
                /userfiles/** = anon
                ${adminPath}/cas = cas
                ${adminPath}/login = authc
                ${adminPath}/logout = logout
                ${adminPath}/** = user
                /act/editor/** = user
                /ReportServer/** = user
            </value>
        </constructor-arg>
    </bean>
    
    <!-- 安全认证过滤器 -->
    <bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean">
        <property name="securityManager" ref="securityManager" />
        <property name="loginUrl" value="${adminPath}/login" />
        <property name="successUrl" value="${adminPath}?login" />
        <property name="filters">
            <map>
                <entry key="cas" value-ref="casFilter"/>
                <entry key="authc" value-ref="formAuthenticationFilter"/>
            </map>
        </property>
        <property name="filterChainDefinitions">
            <ref bean="shiroFilterChainDefinitions"/>
        </property>
    </bean>
    
    <!-- CAS认证过滤器 -->  
    <bean id="casFilter" class="org.apache.shiro.cas.CasFilter">  
        <property name="failureUrl" value="${adminPath}/login"/>
    </bean>
    
    <!-- 定义Shiro安全管理配置 -->
    <bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager">
        <property name="realm" ref="systemAuthorizingRealm" />
        <property name="sessionManager" ref="sessionManager" />
        <property name="cacheManager" ref="shiroCacheManager" />
    </bean>
    
    <!-- 自定义会话管理配置 -->
    <bean id="sessionManager" class="com.thinkgem.jeesite.common.security.shiro.session.SessionManager"> 
        <property name="sessionDAO" ref="sessionDAO"/>
        
        <!-- 会话超时时间，单位：毫秒  -->
        <property name="globalSessionTimeout" value="${session.sessionTimeout}"/>
        
        <!-- 定时清理失效会话, 清理用户直接关闭浏览器造成的孤立会话   -->
        <property name="sessionValidationInterval" value="${session.sessionTimeoutClean}"/>
<!--        <property name="sessionValidationSchedulerEnabled" value="false"/> -->
        <property name="sessionValidationSchedulerEnabled" value="true"/>
        
        <property name="sessionIdCookie" ref="sessionIdCookie"/>
        <property name="sessionIdCookieEnabled" value="true"/>
    </bean>
    
    <!-- 指定本系统SESSIONID, 默认为: JSESSIONID 问题: 与SERVLET容器名冲突, 如JETTY, TOMCAT 等默认JSESSIONID,
        当跳出SHIRO SERVLET时如ERROR-PAGE容器会为JSESSIONID重新分配值导致登录会话丢失! -->
    <bean id="sessionIdCookie" class="org.apache.shiro.web.servlet.SimpleCookie">
        <constructor-arg name="name" value="jeesite.session.id"/>
    </bean>

    <!-- 自定义Session存储容器 -->
<!--    <bean id="sessionDAO" class="com.thinkgem.jeesite.common.security.shiro.session.JedisSessionDAO"> -->
<!--        <property name="sessionIdGenerator" ref="idGen" /> -->
<!--        <property name="sessionKeyPrefix" value="${redis.keyPrefix}_session_" /> -->
<!--    </bean> -->
    <bean id="sessionDAO" class="com.thinkgem.jeesite.common.security.shiro.session.CacheSessionDAO">
        <property name="sessionIdGenerator" ref="idGen" />
        <property name="activeSessionsCacheName" value="activeSessionsCache" />
        <property name="cacheManager" ref="shiroCacheManager" />
    </bean>
    
    <!-- 自定义系统缓存管理器-->
<!--    <bean id="shiroCacheManager" class="com.thinkgem.jeesite.common.security.shiro.cache.JedisCacheManager"> -->
<!--        <property name="cacheKeyPrefix" value="${redis.keyPrefix}_cache_" /> -->
<!--    </bean> -->
    <bean id="shiroCacheManager" class="org.apache.shiro.cache.ehcache.EhCacheManager">
        <property name="cacheManager" ref="cacheManager"/>
    </bean>
    
    <!-- 保证实现了Shiro内部lifecycle函数的bean执行 -->
    <bean id="lifecycleBeanPostProcessor" class="org.apache.shiro.spring.LifecycleBeanPostProcessor"/>
    
    <!-- AOP式方法级权限检查  -->
    <bean class="org.springframework.aop.framework.autoproxy.DefaultAdvisorAutoProxyCreator" depends-on="lifecycleBeanPostProcessor">
        <property name="proxyTargetClass" value="true" />
    </bean>
    <bean class="org.apache.shiro.spring.security.interceptor.AuthorizationAttributeSourceAdvisor">
        <property name="securityManager" ref="securityManager"/>
    </bean>

4.shiro的登录

@Service
public class FormAuthenticationFilter extends org.apache.shiro.web.filter.authc.FormAuthenticationFilter {

    private static final Logger LOGGER = LoggerFactory.getLogger(FormAuthenticationFilter.class);

    public static final String DEFAULT_CAPTCHA_PARAM = "validateCode";
    public static final String DEFAULT_MOBILE_PARAM = "mobileLogin";
    public static final String DEFAULT_MESSAGE_PARAM = "message";

    private String captchaParam = DEFAULT_CAPTCHA_PARAM;
    private String mobileLoginParam = DEFAULT_MOBILE_PARAM;
    private String messageParam = DEFAULT_MESSAGE_PARAM;

    protected AuthenticationToken createToken(ServletRequest request, ServletResponse response) {
        String username = getUsername(request);
        String password = getPassword(request);
        if (password == null) {
            password = "";
        }
        boolean rememberMe = isRememberMe(request);
        String host = StringUtils.getRemoteAddr((HttpServletRequest) request);
        String captcha = getCaptcha(request);
        boolean mobile = isMobileLogin(request);
        return new UsernamePasswordToken(username, password.toCharArray(), rememberMe, host, captcha, mobile);
    }

    /**
     * 每次请求的时候都先进入此方法
     *
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean onAccessDenied(ServletRequest request,
                                     ServletResponse response) throws Exception {
        HttpServletResponse resp = (HttpServletResponse) response;
        HttpServletRequest resq = (HttpServletRequest) request;
        // 后台form
        if (isLoginRequest(request, response)) {
            if (isLoginSubmission(request, response)) {
                return executeLogin(request, response);
            } else {
                return true;
            }
        } else {
            // ajax请求
            if ("XMLHttpRequest"
                    .equalsIgnoreCase(((HttpServletRequest) request)
                            .getHeader("X-Requested-With"))) {
                saveRequestAndRedirectToLogin(request, response);
            } else {
                request.setCharacterEncoding("utf-8");
                resp.setHeader("Content-type", "text/html;charset=UTF-8");
                resp.setCharacterEncoding("utf-8");

                Result result = ResultGenerator.getNotLoginResult(
                        new String("没有登录,请登录".getBytes(), "UTF-8"));
                resp.getWriter().write(JSON.toJSONString(result));
                resp.getWriter().flush();
                resp.getWriter().close();
            }
            return false;
        }
    }

    /**
     * 获取登录用户名
     */

    protected String getUsername(ServletRequest request, ServletResponse response) {
        String username = super.getUsername(request);
        if (StringUtils.isBlank(username)) {
            username = StringUtils.toString(request.getAttribute(getUsernameParam()), StringUtils.EMPTY);
        }
        return username;
    }

    /**
     * 获取登录密码
     */
    @Override
    protected String getPassword(ServletRequest request) {
        String password = super.getPassword(request);
        if (StringUtils.isBlank(password)) {
            password = StringUtils.toString(request.getAttribute(getPasswordParam()), StringUtils.EMPTY);
        }
        return password;
    }

    /**
     * 获取记住我
     */
    @Override
    protected boolean isRememberMe(ServletRequest request) {
        String isRememberMe = WebUtils.getCleanParam(request, getRememberMeParam());
        if (StringUtils.isBlank(isRememberMe)) {
            isRememberMe = StringUtils.toString(request.getAttribute(getRememberMeParam()), StringUtils.EMPTY);
        }
        return StringUtils.toBoolean(isRememberMe);
    }

    public String getCaptchaParam() {
        return captchaParam;
    }

    protected String getCaptcha(ServletRequest request) {
        return WebUtils.getCleanParam(request, getCaptchaParam());
    }

    public String getMobileLoginParam() {
        return mobileLoginParam;
    }

    protected boolean isMobileLogin(ServletRequest request) {
        return WebUtils.isTrue(request, getMobileLoginParam());
    }

    public String getMessageParam() {
        return messageParam;
    }

    /**
     * 登录成功之后跳转URL
     */
    public String getSuccessUrl() {
        return super.getSuccessUrl();
    }

    @Override
    protected void issueSuccessRedirect(ServletRequest request,
                                        ServletResponse response) throws Exception {
        SystemAuthorizingRealm.Principal p = UserUtils.getPrincipal();
        if (p != null && !p.isMobileLogin()) {
            WebUtils.issueRedirect(request, response, getSuccessUrl(), null, true);
        }
//        else {
//            super.issueSuccessRedirect(request, response);
//        }
    }


    /**
     * 登录成功回调
     *
     * @param token
     * @param subject
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean onLoginSuccess(AuthenticationToken token, Subject subject, ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest resq = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;
        // 返回ajax数据
        if (!isBackground(request)) {
            request.setCharacterEncoding("utf-8");
            resp.setHeader("Content-type", "text/html;charset=UTF-8");
            resp.setCharacterEncoding("utf-8");
            String tokenId = (String) UserUtils.getSession().getId();
            Map tokenMap = Maps.newHashMapWithExpectedSize(1);
            tokenMap.put(Global.TOKEN, tokenId);
            Result result = ResultGenerator.getSuccessResult(tokenMap);
            response.getWriter().write(JSON.toJSONString(result));
            response.getWriter().flush();
            response.getWriter().close();
        } else {
            // modelandview方式
            issueSuccessRedirect(request, response);
        }
        return false;
    }

    /**
     * 登录失败调用事件
     */
    @Override
    protected boolean onLoginFailure(AuthenticationToken token,
                                     AuthenticationException e, ServletRequest request, ServletResponse response) {
        HttpServletResponse resp = (HttpServletResponse) response;
        String className = e.getClass().getName(), message = "";

        // 返回json格式信息

        if (IncorrectCredentialsException.class.getName().equals(className)
                || UnknownAccountException.class.getName().equals(className)) {
            message = "用户或密码错误, 请重试.";
        } else if (e.getMessage() != null && StringUtils.startsWith(e.getMessage(), "msg:")) {
            message = StringUtils.replace(e.getMessage(), "msg:", "");
        } else {
            message = "系统出现点问题，请稍后再试！";
            e.printStackTrace(); // 输出到控制台
        }
        Result result = ResultGenerator.getFailResult(message);

        // 返回ajax信息
        if (!isBackground(request)) {
            try {
                request.setCharacterEncoding("utf-8");
                resp.setHeader("Content-type", "text/html;charset=UTF-8");
                resp.setCharacterEncoding("utf-8");
                response.getWriter().write(JSON.toJSONString(result));
                response.getWriter().flush();
                response.getWriter().close();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        } else {
            request.setAttribute(getFailureKeyAttribute(), className);
            request.setAttribute(getMessageParam(), message);
        }
        return true;
    }


    private boolean isBackground(ServletRequest request) {
        if ("XMLHttpRequest"
                .equalsIgnoreCase(((HttpServletRequest) request)
                        .getHeader("X-Requested-With"))) {
            return true;
        }
        return false;
    }
}

5.系统的认证实现类

@Service
//@DependsOn({"userDao","roleDao","menuDao"})
public class SystemAuthorizingRealm extends AuthorizingRealm {

    private Logger logger = LoggerFactory.getLogger(getClass());
    
    private SystemService systemService;
    
    public SystemAuthorizingRealm() {
        this.setCachingEnabled(false);
    }

    @Override
    protected void assertCredentialsMatch(AuthenticationToken token, AuthenticationInfo info) throws AuthenticationException {
        super.assertCredentialsMatch(token, info);
    }

    /**
     * 认证回调函数, 登录时调用
     */
    @Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authcToken) {
        UsernamePasswordToken token = (UsernamePasswordToken) authcToken;
        
        int activeSessionSize = getSystemService().getSessionDao().getActiveSessions(false).size();
        if (logger.isDebugEnabled()){
            logger.debug("login submit, active session size: {}, username: {}", activeSessionSize, token.getUsername());
        }
        
        // 校验登录验证码
        if (LoginController.isValidateCodeLogin(token.getUsername(), false, false)){
            Session session = UserUtils.getSession();
            String code = (String)session.getAttribute(ValidateCodeServlet.VALIDATE_CODE);
            if (token.getCaptcha() == null || !token.getCaptcha().toUpperCase().equals(code)){
                throw new AuthenticationException("msg:验证码错误, 请重试.");
            }
        }
        
        // 校验用户名密码
        User user = getSystemService().getUserByLoginName(token.getUsername());
        if (user != null) {
            if (Global.NO.equals(user.getLoginFlag())){
                throw new AuthenticationException("msg:该已帐号禁止登录.");
            }
            byte[] salt = Encodes.decodeHex(user.getPassword().substring(0,16));
            return new SimpleAuthenticationInfo(new Principal(user, token.isMobileLogin()), 
                    user.getPassword().substring(16), ByteSource.Util.bytes(salt), getName());
        } else {
            return null;
        }
    }
    
    /**
     * 获取权限授权信息，如果缓存中存在，则直接从缓存中获取，否则就重新获取， 登录成功后调用
     */
    protected AuthorizationInfo getAuthorizationInfo(PrincipalCollection principals) {
        if (principals == null) {
            return null;
        }
        
        AuthorizationInfo info = null;

        info = (AuthorizationInfo)UserUtils.getCache(UserUtils.CACHE_AUTH_INFO);

        if (info == null) {
            info = doGetAuthorizationInfo(principals);
            if (info != null) {
                UserUtils.putCache(UserUtils.CACHE_AUTH_INFO, info);
            }
        }

        return info;
    }

    /**
     * 授权查询回调函数, 进行鉴权但缓存中无用户的授权信息时调用
     */
    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
        Principal principal = (Principal) getAvailablePrincipal(principals);
        // 获取当前已登录的用户
        if (!Global.TRUE.equals(Global.getConfig("user.multiAccountLogin"))){
            Collection<Session> sessions = getSystemService().getSessionDao().getActiveSessions(true, principal, UserUtils.getSession());
            if (sessions.size() > 0){
                // 如果是登录进来的，则踢出已在线用户
                if (UserUtils.getSubject().isAuthenticated()){
                    for (Session session : sessions){
                        getSystemService().getSessionDao().delete(session);
                    }
                }
                // 记住我进来的，并且当前用户已登录，则退出当前用户提示信息。
                else{
                    UserUtils.getSubject().logout();
                    throw new AuthenticationException("msg:账号已在其它地方登录，请重新登录。");
                }
            }
        }
        User user = getSystemService().getUserByLoginName(principal.getLoginName());
        if (user != null) {
            SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
            List<Menu> list = UserUtils.getMenuList();
            for (Menu menu : list){
                if (StringUtils.isNotBlank(menu.getPermission())){
                    // 添加基于Permission的权限信息
                    for (String permission : StringUtils.split(menu.getPermission(),",")){
                        info.addStringPermission(permission);
                    }
                }
            }
            // 添加用户权限
            info.addStringPermission("user");
            // 添加用户角色信息
            for (Role role : user.getRoleList()){
                info.addRole(role.getEnname());
            }
            // 更新登录IP和时间
            getSystemService().updateUserLoginInfo(user);
            // 记录登录日志
            LogUtils.saveLog(Servlets.getRequest(), "系统登录");
            return info;
        } else {
            return null;
        }
    }
    
    @Override
    protected void checkPermission(Permission permission, AuthorizationInfo info) {
        authorizationValidate(permission);
        super.checkPermission(permission, info);
    }
    
    @Override
    protected boolean[] isPermitted(List<Permission> permissions, AuthorizationInfo info) {
        if (permissions != null && !permissions.isEmpty()) {
            for (Permission permission : permissions) {
                authorizationValidate(permission);
            }
        }
        return super.isPermitted(permissions, info);
    }
    
    @Override
    public boolean isPermitted(PrincipalCollection principals, Permission permission) {
        authorizationValidate(permission);
        return super.isPermitted(principals, permission);
    }
    
    @Override
    protected boolean isPermittedAll(Collection<Permission> permissions, AuthorizationInfo info) {
        if (permissions != null && !permissions.isEmpty()) {
            for (Permission permission : permissions) {
                authorizationValidate(permission);
            }
        }
        return super.isPermittedAll(permissions, info);
    }
    
    /**
     * 授权验证方法
     * @param permission
     */
    private void authorizationValidate(Permission permission){
        // 模块授权预留接口
    }
    
    /**
     * 设定密码校验的Hash算法与迭代次数
     */
    @PostConstruct
    public void initCredentialsMatcher() {
        HashedCredentialsMatcher matcher = new HashedCredentialsMatcher(SystemService.HASH_ALGORITHM);
        matcher.setHashIterations(SystemService.HASH_INTERATIONS);
        setCredentialsMatcher(matcher);
    }
    
//  /**
//   * 清空用户关联权限认证，待下次使用时重新加载
//   */
//  public void clearCachedAuthorizationInfo(Principal principal) {
//      SimplePrincipalCollection principals = new SimplePrincipalCollection(principal, getName());
//      clearCachedAuthorizationInfo(principals);
//  }

    /**
     * 清空所有关联认证
     * @Deprecated 不需要清空，授权缓存保存到session中
     */
    @Deprecated
    public void clearAllCachedAuthorizationInfo() {
//      Cache<Object, AuthorizationInfo> cache = getAuthorizationCache();
//      if (cache != null) {
//          for (Object key : cache.keys()) {
//              cache.remove(key);
//          }
//      }
    }

    /**
     * 获取系统业务对象
     */
    public SystemService getSystemService() {
        if (systemService == null){
            systemService = SpringContextHolder.getBean(SystemService.class);
        }
        return systemService;
    }
    
    /**
     * 授权用户信息
     */
    public static class Principal implements Serializable {

        private static final long serialVersionUID = 1L;
        
        private String id; // 编号
        private String loginName; // 登录名
        private String name; // 姓名
        private boolean mobileLogin; // 是否手机登录
        
//      private Map<String, Object> cacheMap;

        public Principal(User user, boolean mobileLogin) {
            this.id = user.getId();
            this.loginName = user.getLoginName();
            this.name = user.getName();
            this.mobileLogin = mobileLogin;
        }

        public String getId() {
            return id;
        }

        public String getLoginName() {
            return loginName;
        }

        public String getName() {
            return name;
        }

        public boolean isMobileLogin() {
            return mobileLogin;
        }

//      @JsonIgnore
//      public Map<String, Object> getCacheMap() {
//          if (cacheMap==null){
//              cacheMap = new HashMap<String, Object>();
//          }
//          return cacheMap;
//      }

        /**
         * 获取SESSIONID
         */
        public String getSessionid() {
            try{
                return (String) UserUtils.getSession().getId();
            }catch (Exception e) {
                return "";
            }
        }
        
        @Override
        public String toString() {
            return id;
        }

    }
}

6.UsernamePasswordToken

public class UsernamePasswordToken extends org.apache.shiro.authc.UsernamePasswordToken {

    private static final long serialVersionUID = 1L;

    private String captcha;
    private boolean mobileLogin;
    
    public UsernamePasswordToken() {
        super();
    }

    public UsernamePasswordToken(String username, char[] password,
            boolean rememberMe, String host, String captcha, boolean mobileLogin) {
        super(username, password, rememberMe, host);
        this.captcha = captcha;
        this.mobileLogin = mobileLogin;
    }

    public String getCaptcha() {
        return captcha;
    }

    public void setCaptcha(String captcha) {
        this.captcha = captcha;
    }

    public boolean isMobileLogin() {
        return mobileLogin;
    }
    
}

7.sessionDao

public interface SessionDAO extends org.apache.shiro.session.mgt.eis.SessionDAO {

    /**
     * 获取活动会话
     * @param includeLeave 是否包括离线（最后访问时间大于3分钟为离线会话）
     * @return
     */
    public Collection<Session> getActiveSessions(boolean includeLeave);
    
    /**
     * 获取活动会话
     * @param includeLeave 是否包括离线（最后访问时间大于3分钟为离线会话）
     * @param principal 根据登录者对象获取活动会话
     * @param filterSession 不为空，则过滤掉（不包含）这个会话。
     * @return
     */
    public Collection<Session> getActiveSessions(boolean includeLeave, Object principal, Session filterSession);
    
}

7.自定义web会话管理类

public class SessionManager extends DefaultWebSessionManager {

    private static final Logger LOGGER = LoggerFactory.getLogger(SessionManager.class);

    public SessionManager() {
        super();
    }

    @Override
    protected Serializable getSessionId(ServletRequest request, ServletResponse response) {
        LOGGER.info("根据token获取sessionID，确定用户是否登录");

        // 如果参数中包含“__sid”参数，则使用此sid会话。 例如：http://localhost/project?__sid=xxx&__cookie=true
        String sid = request.getParameter("__sid");
        if (StringUtils.isNotBlank(sid)) {
            // 是否将sid保存到cookie，浏览器模式下使用此参数。
            if (WebUtils.isTrue(request, "__cookie")) {
                HttpServletRequest rq = (HttpServletRequest) request;
                HttpServletResponse rs = (HttpServletResponse) response;
                Cookie template = getSessionIdCookie();
                Cookie cookie = new SimpleCookie(template);
                cookie.setValue(sid);
                cookie.saveTo(rq, rs);
            }
            // 设置当前session状态
            request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID_SOURCE,
                    ShiroHttpServletRequest.URL_SESSION_ID_SOURCE); // session来源与url
            request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID, sid);
            request.setAttribute(ShiroHttpServletRequest.REFERENCED_SESSION_ID_IS_VALID, Boolean.TRUE);
            return sid;
        } else {
            return super.getSessionId(request, response);
        }
    }

    @Override
    public void validateSessions() {
        super.validateSessions();
    }

    @Override
    protected Session retrieveSession(SessionKey sessionKey) {
        try {
            return super.retrieveSession(sessionKey);
        } catch (UnknownSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public Date getStartTimestamp(SessionKey key) {
        try {
            return super.getStartTimestamp(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public Date getLastAccessTime(SessionKey key) {
        try {
            return super.getLastAccessTime(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public long getTimeout(SessionKey key) {
        try {
            return super.getTimeout(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return 0;
        }
    }

    public void setTimeout(SessionKey key, long maxIdleTimeInMillis) {
        try {
            super.setTimeout(key, maxIdleTimeInMillis);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
        }
    }

    public void touch(SessionKey key) {
        try {
            super.touch(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
        }
    }

    public String getHost(SessionKey key) {
        try {
            return super.getHost(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public Collection<Object> getAttributeKeys(SessionKey key) {
        try {
            return super.getAttributeKeys(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public Object getAttribute(SessionKey sessionKey, Object attributeKey) {
        try {
            return super.getAttribute(sessionKey, attributeKey);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public void setAttribute(SessionKey sessionKey, Object attributeKey, Object value) {
        try {
            super.setAttribute(sessionKey, attributeKey, value);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
        }
    }

    public Object removeAttribute(SessionKey sessionKey, Object attributeKey) {
        try {
            return super.removeAttribute(sessionKey, attributeKey);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
            return null;
        }
    }

    public void stop(SessionKey key) {
        try {
            super.stop(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
        }
    }

    public void checkValid(SessionKey key) {
        try {
            super.checkValid(key);
        } catch (InvalidSessionException e) {
            // 获取不到SESSION不抛出异常
        }
    }

    @Override
    protected Session doCreateSession(SessionContext context) {
        try {
            return super.doCreateSession(context);
        } catch (IllegalStateException e) {
            return null;
        }
    }

    @Override
    protected Session newSessionInstance(SessionContext context) {
        Session session = super.newSessionInstance(context);
        session.setTimeout(getGlobalSessionTimeout());
        return session;
    }

    @Override
    public Session start(SessionContext context) {
        try {
            return super.start(context);
        } catch (NullPointerException e) {
            SimpleSession session = new SimpleSession();
            session.setId(0);
            return session;
        }
    }
}

8.session缓存dao

public class CacheSessionDAO extends EnterpriseCacheSessionDAO implements SessionDAO {

    private Logger logger = LoggerFactory.getLogger(getClass());
    
    public CacheSessionDAO() {
        super();
    }

    @Override
    protected void doUpdate(Session session) {
        if (session == null || session.getId() == null) {  
            return;
        }
        
        HttpServletRequest request = Servlets.getRequest();
        if (request != null){
            String uri = request.getServletPath();
            // 如果是静态文件，则不更新SESSION
            if (Servlets.isStaticFile(uri)){
                return;
            }
            // 如果是视图文件，则不更新SESSION
            if (StringUtils.startsWith(uri, Global.getConfig("web.view.prefix"))
                    && StringUtils.endsWith(uri, Global.getConfig("web.view.suffix"))){
                return;
            }
            // 手动控制不更新SESSION
            String updateSession = request.getParameter("updateSession");
            if (Global.FALSE.equals(updateSession) || Global.NO.equals(updateSession)){
                return;
            }
        }
        super.doUpdate(session);
        logger.debug("update {} {}", session.getId(), request != null ? request.getRequestURI() : "");
    }

    @Override
    protected void doDelete(Session session) {
        if (session == null || session.getId() == null) {  
            return;
        }
        
        super.doDelete(session);
        logger.debug("delete {} ", session.getId());
    }

    @Override
    protected Serializable doCreate(Session session) {
        HttpServletRequest request = Servlets.getRequest();
        if (request != null){
            String uri = request.getServletPath();
            // 如果是静态文件，则不创建SESSION
            if (Servlets.isStaticFile(uri)){
                return null;
            }
        }
        super.doCreate(session);
        logger.debug("doCreate {} {}", session, request != null ? request.getRequestURI() : "");
        return session.getId();
    }

    @Override
    protected Session doReadSession(Serializable sessionId) {
        return super.doReadSession(sessionId);
    }
    
    @Override
    public Session readSession(Serializable sessionId) throws UnknownSessionException {
        try{
            Session s = null;
            HttpServletRequest request = Servlets.getRequest();
            if (request != null){
                String uri = request.getServletPath();
                // 如果是静态文件，则不获取SESSION
                if (Servlets.isStaticFile(uri)){
                    return null;
                }
                s = (Session)request.getAttribute("session_"+sessionId);
            }
            if (s != null){
                return s;
            }

            Session session = super.readSession(sessionId);
            logger.debug("readSession {} {}", sessionId, request != null ? request.getRequestURI() : "");
            
            if (request != null && session != null){
                request.setAttribute("session_"+sessionId, session);
            }
            
            return session;
        }catch (UnknownSessionException e) {
            return null;
        }
    }

    /**
     * 获取活动会话
     * @param includeLeave 是否包括离线（最后访问时间大于3分钟为离线会话）
     * @return
     */
    @Override
    public Collection<Session> getActiveSessions(boolean includeLeave) {
        return getActiveSessions(includeLeave, null, null);
    }
    
    /**
     * 获取活动会话
     * @param includeLeave 是否包括离线（最后访问时间大于3分钟为离线会话）
     * @param principal 根据登录者对象获取活动会话
     * @param filterSession 不为空，则过滤掉（不包含）这个会话。
     * @return
     */
    @Override
    public Collection<Session> getActiveSessions(boolean includeLeave, Object principal, Session filterSession) {
        // 如果包括离线，并无登录者条件。
        if (includeLeave && principal == null){
            return getActiveSessions();
        }
        Set<Session> sessions = Sets.newHashSet();
        for (Session session : getActiveSessions()){
            boolean isActiveSession = false;
            // 不包括离线并符合最后访问时间小于等于3分钟条件。
            if (includeLeave || DateUtils.pastMinutes(session.getLastAccessTime()) <= 3){
                isActiveSession = true;
            }
            // 符合登陆者条件。
            if (principal != null){
                PrincipalCollection pc = (PrincipalCollection)session.getAttribute(DefaultSubjectContext.PRINCIPALS_SESSION_KEY);
                if (principal.toString().equals(pc != null ? pc.getPrimaryPrincipal().toString() : StringUtils.EMPTY)){
                    isActiveSession = true;
                }
            }
            // 过滤掉的SESSION
            if (filterSession != null && filterSession.getId().equals(session.getId())){
                isActiveSession = false;
            }
            if (isActiveSession){
                sessions.add(session);
            }
        }
        return sessions;
    }
    
}