public class LoginController{

  private static final String SESSION_ID_COOKIE = "sessionId";

  @Autowired
  private RedisClient client;

  @RequestMapping(value="/login/index")
  public ModelAndView login(HttpServletRequest request, HttpServletResponse response){
    ModelAndView modelAndView = new ModelAndView("/login");
    String sessionId = CookieUtils.getCookieValue(request, SESSION_ID_COOKIE);
    if(StringUtils.isEmptyOrNull(sessionId)) {
      sessionId = getUniqueSessionId();
      addCookie(response, SESSION_ID_COOKIE, sessionId);
    }
    // 其它业务相关信息

    return modelAndView;
  }

  // 添加cookie到response
  private void addCookie(HttpServletResponse response, String cookieName, String cookieValue) {
    Cookie cookie = new Cookie(cookieName, cookieValue);
    cookie.setPath("/");
    cookie.setMaxAge(-1);
    response.addCookie(cookie);
  }

  // 获取唯一sessionid
  private String getUniqueSessionId() {
    String sessionId = "";
    while(true) {
      String uuid = UUID.randomUUID().toString();
      String[] jsessionIdArray = uuid.split("-");
      StringBuilder jsessionIdBuilder = new StringBuilder();
      for(String str: jsessionIdArray) {
        jsessionIdBuilder.append(str);
      }
      sessionId = jsessionIdBuilder.toString();
      if(!redisClient.exists(sessionId)) {
        break;
      }
    }
    return sessionId;
  }
}

public class LoginController{

  private static final String SESSION_ID_COOKIE = "sessionId";

  private static final Integer REDIS_SESSION_TIME_SECONDS = 2 * 60 * 60;

  @Autowired
  private RedisClient client;

  @RequestMapping(value="/authenticate")
  @ResponseBody
  public ResponseInfo login(String username, String password, HttpServletRequest request){
    ResponseInfo<Object> responseInfo = new ResponseInfo<Object>();
    try {
      Account account = authenticate(username, password);

      saveSession(account);
      responseInfo.setStatus(0);
      responseInfo.setMessage("success");
    } catch(Exceptioin e){
      responseInfo.setStatus(1);
      responseInfo.setMessage("服务器正忙,请稍候重试")
    }

    return responseInfo;
  }

  // 保存session信息
  private void saveSession(Account account) {
    String sessionId = CookieUtils.getCookieValue(request, SESSION_ID_COOKIE);
    redisClient.set(sessionId, account);
    redisClient.expire(sessionId, REDIS_SESSION_TIME_SECONDS);
  }
}

public class LoginController{

  private static final String SESSION_ID_COOKIE = "sessionId";

  @Autowired
  private RedisClient client;

  @RequestMapping(value="/logout", method = RequestMethod.GET)
  public void logout(HttpServletRequest request, HttpServletResponse response) {
    // 获取到重定向位置也就是登录页
    String redirectUrl = this.getLoginPageRedirectUrl(request);

    clearSession(request);
    clearSessionCookie(request, response);
    response.sendRedirect(redirectUrl);
  }

  // 删除session在redis里面的信息
  private void clearSession(HttpServletRequest request) {
    String sessionId = CookieUtils.getCookieValue(request, SESSION_ID_COOKIE);
    redisClient.del(sessionId);
  }

  // 删除session在cookie中的sessionid
  private void clearSessionCookie(HttpServletRequest request, HttpServletResponse response) {
    Cookie sessionCookie = CookieUtils.getCookie(request, SESSION_ID_COOKIE);
    sessionCookie.setMaxAge(0);
    response.addCookie(sessionCookie);
  }
}

public class BaseController{

  @Autowired
  private RedisClient redisClient;

  protected Account getAccountFromSession(HttpServletRequest request) {
    String sessionCookieValue = CookieUtils.getCookieValue(request, "sessionid");
    if(StringUtils.isEmptyOrNull(sessionCookieValue)) {
      return null;
    } else {
      String accountJson = this.redisClient.get(sessionCookieValue);
      Account account = null;
      if(!StringUtils.isEmpty(accountJson)) {
        account = (Account)JSON.parseObject(casInfoJson, Account.class);
      }

      return account;
    }
  }

}