shiro 实现单用户登录，一个用户同一时刻只能在一个地方登录

[main]
# Objects and their properties are defined here,
# Such as the securityManager, Realms and anything
# else needed to build the SecurityManager
authc.loginUrl = /login.jsp
authc.successUrl = /web/index.jsp

#cache manager
builtInCacheManager = org.apache.shiro.cache.MemoryConstrainedCacheManager
securityManager=org.apache.shiro.web.mgt.DefaultWebSecurityManager
securityManager.cacheManager = $builtInCacheManager
securityManager.sessionManager=$sessionManager

#session 必须配置session，强制退出时，通过将session移除实现
sessionManager=org.apache.shiro.web.session.mgt.DefaultWebSessionManager
sessionManager.sessionDAO=$sessionDAO

sessionDAO=org.apache.shiro.session.mgt.eis.MemorySessionDAO

# Create ldap realm
ldapRealm = org.apache.shiro.realm.ldap.JndiLdapRealm
#......

# Configure JDBC realm datasource
dataSource = org.postgresql.ds.PGPoolingDataSource
#.......


# Create JDBC realm.
jdbcRealm.permissionsLookupEnabled = true
jdbcRealm = org.apache.shiro.realm.jdbc.JdbcRealm
jdbcRealm.userRolesQuery = ......
jdbcRealm.permissionsQuery = ......
jdbcRealm.dataSource = $dataSource

#self realm
localAuthorizingRealm = com.redbudtek.shiro.LocalAuthorizingRealm

securityManager.realms = $ldapRealm, $localAuthorizingRealm

@Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authenticationToken) throws AuthenticationException {
        String userName = (String)authenticationToken.getPrincipal();

        //处理session
        DefaultWebSecurityManager securityManager = (DefaultWebSecurityManager) SecurityUtils.getSecurityManager();
        DefaultWebSessionManager sessionManager = (DefaultWebSessionManager)securityManager.getSessionManager();
        Collection<Session> sessions = sessionManager.getSessionDAO().getActiveSessions();//获取当前已登录的用户session列表
        for(Session session:sessions){
            //清除该用户以前登录时保存的session
            if(userName.equals(String.valueOf(session.getAttribute(DefaultSubjectContext.PRINCIPALS_SESSION_KEY)))) {
                sessionManager.getSessionDAO().delete(session);
            }
        }

        String pwd = null;
        return new SimpleAuthenticationInfo(userName,pwd,getName());
    }