@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
    String jwt = resolveToken(request);
    //重復登錄只校驗帶有合法jwt的  放過驗證碼以及免鑒權的那些請求
    if (null == jwt || "null".equalsIgnoreCase(jwt) || !this.tokenProvider.validateToken(jwt)) {
        filterChain.doFilter(request, response);
        return;
    }

    if (isAccessAllowed(jwt)) {
        filterChain.doFilter(request, response);
        return;
    }

    // 賬號重復登錄，跳轉(zhuǎn)登錄頁面 logout
    logout(response);
}

/**
 * 重復登錄核心校驗
 * @param token 當前token
 * @return true通過放行 
 */
private boolean isAccessAllowed(String token) {
    Authentication authentication = this.tokenProvider.getAuthentication(token);
    String redisToken = redisTemplate.opsForValue().get(Constants.PREFIX_LOGIN_USER+authentication.getName());
    //redisToken為空 說明第一次登陸 放過并加入redis
    if(!StringUtils.hasLength(redisToken)){
        redisTemplate.opsForValue().set(Constants.PREFIX_LOGIN_USER+authentication.getName(),token,
          86400, TimeUnit.SECONDS);
        return true;
    }
    //redis token和當前token一致  說明是當前登陸用戶訪問  放過
    if(token.equals(redisToken)){
        return true;
    }
    //redis token和當前token不一致，比較兩個token的創(chuàng)建時間，如果當前token大于redistoken 就說當前是最新的，放入redis并放過
    //否則就說明redis里已有最新的token，當前token應該過期，不放行
    Date date = this.tokenProvider.getIssueAt(token);
    Date redisDate = this.tokenProvider.getIssueAt(redisToken);
    if(date.after(redisDate)){
        redisTemplate.opsForValue().set(Constants.PREFIX_LOGIN_USER+authentication.getName(),token,
          86400, TimeUnit.SECONDS);
        return true;
    }else{
        return false;
    }

}

/**
* 獲取jwt
/
private String resolveToken(HttpServletRequest request) {
    String bearerToken = request.getHeader("Authorization");
    if (StringUtils.hasText(bearerToken) && bearerToken.startsWith("Bearer ")) {
        return bearerToken.substring(7);
    }
    return null;
}

/**
 * 返回退出信息到前臺
 * @param response
 */
private void logout(HttpServletResponse response){
    response.setStatus(HttpStatus.FORBIDDEN.value());
    response.setContentType(MediaType.APPLICATION_JSON_UTF8_VALUE);
    try {
        JSONObject resultObj = new JSONObject();
        resultObj.putOnce("data","賬號已在別的地方登錄，請重新登錄");
        response.getWriter().print(resultObj.toString());
    } catch (IOException e) {
        e.printStackTrace();
    }
}