电脑端微信授权登录逻辑

一、用户点击授权后先跳转到本地的后台服务器，然后响应302跳转，重定向到微信服务器。

    @Override
    public void oAuth2RedirectURL(OAuthApiDto oAuthApiDto, HttpServletRequest httpServletRequest,
            HttpServletResponse httpServletResponse) {
        String weixin_auth_url = MessageFormat.format(weixin_auth_url_format, oAuthApiDto.getState(),
                oAuthApiDto.getCallbackUrl());
        httpServletResponse.setStatus(HttpStatus.SC_MOVED_TEMPORARILY);
        httpServletResponse.setHeader("location", weixin_auth_url);
    }

二、用户扫码之后，微信将浏览器重定向到TOPPGO，然后进行回调，TOPPGO获取用户的基本信息，根据unionid判单用户是否存在，没有注册，有直接获取信息且生成将要登陆的链接

String code = httpServletRequest.getParameter("code");

        String token_url = MessageFormat.format(token_url_format, code);

        System.out.println(token_url);

        String result = JsoupUtils.getDocumentUseGet(token_url);

        try {
            JSONObject jonJsonObject = JSONObject.parseObject(result);

            String unionid = jonJsonObject.getString("unionid");
            String openid = jonJsonObject.getString("openid");
            LOGGER.info("openid:{},unionid:{}", openid, unionid);

            User userDb = userService.findUserByOpenidOrUnionid(openid, unionid);
            if (userDb != null) {
                // 直接跳转开始进行登录
                redirect2WxLoginAction(unionid, httpServletRequest, httpServletResponse);
            } else {
                String ip = IPUtils.getIP(httpServletRequest);
                User user = new User();
                user.setRegistIp(ip);
                user.setWechatOpenid(unionid);
                // 新增用户的注册来源
                user.setFromType(FromType.WECHAT4PC);
                userService.save(user, null);
                // 开始跳转登录
                redirect2WxLoginAction(unionid, httpServletRequest, httpServletResponse);
            }
        } catch (Exception e) {
            LOGGER.error(e.getMessage(), e);
            LOGGER.info("result:" + JSONObject.toJSONString(result));
        }

三、根据重定向的链接和目的的URL，浏览器重定向，直接登录。

String targetServer = auhtorServer;

        String state = httpServletRequest.getParameter("state");
        if (StringUtils.isNotBlank(state)) {
            if (state.contains(OAuth2AuthController.stateSplitCharacter)) {
                String[] stateSplits = state.split(OAuth2AuthController.stateSplitCharacter);
                if (stateSplits.length > 1) {
                    String targetDomain = stateSplits[1];
                    if (targetDomain.startsWith("http")) {
                        targetServer = targetDomain;
                    } else {
                        targetServer = "http://" + targetDomain;
                    }
                }
            }
        }

        String redirectUrl = MessageFormat.format("{0}/subject/wxRedirect?token=@WX@{1}&wxRedirect={2}", targetServer, unionid,
                targetServer);

        //返回freemark页面
        httpServletResponse.setContentType("text/html;charset=utf-8");
        Template template = configuration.getTemplate("/wxAuth.ftl");
        Map<String,Object> dateModel = Maps.newHashMap();
        dateModel.put("redirectUrl", redirectUrl);
        template.process(dateModel, httpServletResponse.getWriter());