/** 
 * 
 * @ClassName: LoginListenner 
 * @Description: 登录监听类-处理同一时间只允许账号，单地点登录 
 * @author mr_smile2014 605051929@qq.com 
 * @date 2014年11月12日 下午2:23:41 
 * 
 */ 
public class LoginListenner implements HttpSessionAttributeListener { 
  /** 
   * 用于存放账号和session对应关系的map 
   */ 
  private Map<String, HttpSession> map = new HashMap<String, HttpSession>(); 
 
  /** 
   * 当向session中放入数据触发 
   */ 
  public void attributeAdded(HttpSessionBindingEvent event) { 
    String name = event.getName(); 
 
    if (name.equals("loginuser")) { 
      User user = (User) event.getValue(); 
      if (map.get(user.getUserName()) != null) { 
        HttpSession session = map.get(user.getUserName()); 
        session.removeAttribute(user.getUserName()); 
        session.invalidate(); 
      } 
      map.put(user.getUserName(), event.getSession()); 
    } 
 
  } 
  /** 
   * 当向session中移除数据触发 
   */ 
  public void attributeRemoved(HttpSessionBindingEvent event) { 
    String name = event.getName(); 
 
    if (name.equals("loginuser")) { 
      User user = (User) event.getValue(); 
      map.remove(user.getUserName()); 
 
    } 
  } 
 
  public void attributeReplaced(HttpSessionBindingEvent event) { 
 
  } 
 
  public Map<String, HttpSession> getMap() { 
    return map; 
  } 
 
  public void setMap(Map<String, HttpSession> map) { 
    this.map = map; 
  } 
 
} 

/** 
   * 登录 
   * 
   * @param userName 
   * @param passWord 
   * @param code 
   *      验证码 
   * @param type 
   *      登陆类型（商户，操作员） 
   * @param model 
   * @return 
   */ 
  @RequestMapping("/login") 
  public String login(String account, String passWord, String code, 
      Model model, HttpServletRequest request) { 
      //登录验证并返回登录成功用户对象 
      User user=loginResult(userPhone, passWord, code, request); 
      //把用户对象放入到session中，将会触发LoginListenner中的attributeAdded事件 
      request.getSession().setAttribute("loginuser", user); 
       
      } 

<!--一个用户只能在一个主机登录 --> 
  <listener> 
    <listener-class>com.test.listenner.LoginListenner</listener-class> 
  </listener>