前言

使用第三方插件

<dependency>
    <groupId>com.github.binarywang</groupId>
    <artifactId>weixin-java-mp</artifactId>
    <version>4.6.0</version>
</dependency>

准备APPID和appSecet

• 登录微信公众号后台，复制appid和appsecuret。切记如果开发者秘钥已经在使用，请勿重置，否则导致已上线应用无法使用。
• 微信配置，习惯用yml格式

  wechat:
    appId: wx472934ed71cXXX
    secret: 5cf9107ede023fa45ab626c444123a2f
    token: f84542aa3ca2f7e92984dd123683fdac
    aesKey: M5jSic8xaq5YKb8aMMgUo4oaZAs23kLMJ61BcX8Q123
  

• 初始化配置

  @Slf4j
  @Configuration
  public class WxConfiguration {
  
    @Autowired
    private WechatAccountConfig wechatAccountConfig;
  
    @Bean
    public WxMpService wxMpService() {
        WxMpService wxMpService = new WxMpServiceImpl();
        wxMpService.setWxMpConfigStorage(wxMpConfigStorage());
        return wxMpService;
    }
  
    @Bean
    public WxMpConfigStorage wxMpConfigStorage() {
        WxMpDefaultConfigImpl wxMpDefaultConfig = new WxMpDefaultConfigImpl();
        log.info("微信配置文件 ： {}", JSON.toJSONString(wechatAccountConfig));
        wxMpDefaultConfig.setAppId(wechatAccountConfig.getAppId());
        wxMpDefaultConfig.setSecret(wechatAccountConfig.getSecret());
        wxMpDefaultConfig.setToken(wechatAccountConfig.getToken());
        wxMpDefaultConfig.setAesKey(wechatAccountConfig.getAesKey());
        return wxMpDefaultConfig;
    }
  

  @Data
  @Component
  @ConfigurationProperties(value = "wechat")
  public class WechatAccountConfig {
  
    private String appId;
  
    private String secret;
  
    private String token;
  
    private String aesKey;
  }
  

  生成二维码

• 获取二维码方法和扫描状态检查接口

  @Slf4j
  @Api(value = "网关公众号接口", tags = "网关公众号接口")
  @RestController
  @RequestMapping("/gateway/wechat")
  public class WechatSubController {
    @Autowired
    private WxMpService wxMpService;
    @Autowired
    private IWeiXinService weiXinService;
  
    /**
     * 获取微信生成二维码
     */
    @ApiOperation(value = "获取微信二维码")
    @GetMapping(value = "/qrcode/{codeType}")
    public AjaxResult getQrCode(@PathVariable("codeType") String codeType) {
        return AjaxResult.success(weiXinService.getQrCode(MsgEventTypeEnum.getTypeEnum(codeType)));
    }
  
    /**
     * 获取微信生成二维码
     */
    @ApiOperation(value = "获取扫码结果")
    @GetMapping(value = "/getScanResult/{uuid}")
    public AjaxResult getScanResult(@PathVariable("uuid") String uuid) {
        return AjaxResult.success(weiXinService.getScanResult(uuid));
    }
  

• 接口层

  public interface IWeiXinService {
    TicketVo getQrCode(MsgEventTypeEnum msgEventTypeEnum);
  
    String scanQRCodesCallBack(WxMpXmlMessage px);
  
    NatMemberWechat getScanResult(String uuid);
  }
  

• 实现层

  @Slf4j
  @Service
  public class WeiXinServiceImpl implements IWeiXinService {
  
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private WxMpService wxMpService;
    @Autowired
    private INatMemberWechatService natMemberWechatService;
  
    @Override
    public TicketVo getQrCode(MsgEventTypeEnum msgEventTypeEnum) {
        // 这里生成uuid 等下扫码验证微信时，就知道是那个用户扫的码
        // 这个uuid就是上面声明的全局私有变量
        String uuid = UUID.randomUUID().toString();
        Map<String, Object> map = new HashMap<>();
        map.put("uuid", uuid);
        map.put("eventType", msgEventTypeEnum.getEventType());
        stringRedisTemplate.opsForValue().set(RedisKey.WECHAT_SCAN_UUID_FLAG + uuid, JSON.toJSONString(map), 120L, TimeUnit.SECONDS);
  
        WxMpQrCodeTicket ticket = null;
        try {
            // 获取 ticket
            ticket = wxMpService.getQrcodeService().qrCodeCreateTmpTicket(JSON.toJSONString(map), 6400);
        } catch (WxErrorException e) {
            throw new RuntimeException(e);
        }
        String qrUrl = null;
        try {
            // 根据 ticket 换取二维码链接
            qrUrl = wxMpService.getQrcodeService().qrCodePictureUrl(ticket.getTicket());
        } catch (WxErrorException e) {
            throw new RuntimeException(e);
        }
        // 返回二维码链接，我们系统是返回base64编码的，但是代码太长了，我这里直接返回图片的url 和
        //生成的uuid
        TicketVo vo = new TicketVo();
        vo.setImageBase(qrUrl);
        vo.setUuid(uuid);
        return vo;
    }
  

    @Override
    public NatMemberWechat getScanResult(String uuid) {
        String redisData = Objects.toString(stringRedisTemplate.opsForValue().get(RedisKey.WECHAT_SCAN_UUID_RESULT_FLAG + uuid), null);
        if (StringUtils.isEmpty(redisData)) {
            log.debug("redisData is null");
            return null;
        }
        JSONObject jsonObject = JSONObject.parseObject(redisData);
        NatMemberWechat natMemberWechat = natMemberWechatService.selectNatMemberWechatByOpenId(jsonObject.getString("openid"));
        if(natMemberWechat==null){
            natMemberWechat=new NatMemberWechat();
            natMemberWechat.setOpenId(jsonObject.getString("openid"));
            natMemberWechat.setUserId(null);
        }
        return natMemberWechat;
    }
  

  到此，扫码和扫描检查的代码已经写完，接下来配置回调。

  由于回调是微信服务器外网回调服务器，在本地开发是内网，怎么才能让微信调用本地电脑呢，我们就要借助内网穿透。

  内网穿透

• NatCross内网穿透,推荐的原因是免费。可以将局域网个人电脑、服务器映射到公网的内网穿透工具。
• NatCross官网（http://www.natcross.com/）
• 账号注册
• 登录首页如图​​​​​​​
• 配置映射，需要实名认证
• 配置映射，获取生成的访问域名地址​​​​​​​  
• 下载并启动客户端

  下载方式2：windows和linux 版本下载，请点击连接 https://pan.baidu.com/s/16k2jFiWuvtNN5Y8CGNUkzw （提取码：hs9d）
  运行步骤：
  windows版本步骤：
  1、下载window客户端
  2、注册natcross账号
  3、修改config.properties配置文件，修改client.key值改为自己注册的客户端秘钥
  4、双击执行启动client-start.bat
  5、配置添加内网映射或场景映射后，自动连接。
  提示：自带jre，无效安装运行环境。
  linux版本步骤：
  1、下载linux客户端
  2、注册natcross账号
  3、vi config.properties配置文件，修改client.key值改为自己注册的客户端秘钥
  4、执行chmod 777 client-start.sh 授权
  5、执行：启动 ./client-start.sh start ，停止 ./client-start.sh stop ，重启 ./client-start.sh restart
  6、查看logs日志 tail -100f natcross-client-3.0.0.jar.log
  7、配置添加内网映射或场景映射后，自动连接。
  提示： 自带jre，无需再次安装运行环境。
  如有疑问，可以加QQ客服：2496727282 （早9点-晚10点）
  

• 启动成功截图：

  公众号接口配置，将上一步获取到的地址+请求方式配置到微信后台，如图

扫码登录

公众号回调

• 回调代码块实现

  /**
     * 验证微信服务器 此接口不调用
     */
    @ApiOperation(value = "验证微信服务器 此接口不调用")
    @GetMapping(value = "/callback")
    public String checkSign(HttpServletRequest request) {
        String signature = request.getParameter("signature");
        String timestamp = request.getParameter("timestamp");
        String nonce = request.getParameter("nonce");
        String echostr = request.getParameter("echostr");
        log.info("\n接收到来自微信服务器的认证消息：[signature:{}, timestamp:{}, nonce:{}, echostr:{}]", signature, timestamp, nonce, echostr);
        if (!wxMpService.checkSignature(timestamp, nonce, signature)) {
            log.error("【无效的请求】");
            throw new ServiceException("无效的请求", -1);
        }
        return echostr;
    }
  
    /**
     * 响应微信,这一步是关注微信后,响应微信获取信息
     */
    @ApiOperation(value = "微信扫码响应微信服务器")
    @PostMapping("/callback")
    public String scanQRCodesCallBack(HttpServletRequest request, @RequestBody String requestBody) {
        String signature = request.getParameter("signature");
        String timestamp = request.getParameter("timestamp");
        String nonce = request.getParameter("nonce");
        String echostr = request.getParameter("echostr");
        String openid = request.getParameter("openid");
        String encType = request.getParameter("encType");
        String msgSignature = request.getParameter("msgSignature");
        log.info("\n接收到来自微信服务器的认证消息：[signature:{}, timestamp:{}, nonce:{}, echostr:{},encType:{},msgSignature:{}]", signature, timestamp, nonce, echostr, encType, msgSignature);
        if (!wxMpService.checkSignature(timestamp, nonce, signature)) {
            log.error("【无效的请求】");
            throw new ServiceException("无效的请求", -1);
        }
        if (encType == null) {
            // 明文传输的消息
            WxMpXmlMessage inMessage = WxMpXmlMessage.fromXml(requestBody);
            log.debug("\n消息内容为：\n{} ", inMessage.toString());
            return weiXinService.scanQRCodesCallBack(inMessage);
        } else if ("aes".equalsIgnoreCase(encType)) {
            // aes加密的消息
            WxMpXmlMessage inMessage = WxMpXmlMessage.fromEncryptedXml(requestBody, wxMpService.getWxMpConfigStorage(),
                    timestamp, nonce, msgSignature);
            log.debug("\n消息解密后内容为：\n{} ", inMessage.toString());
            return weiXinService.scanQRCodesCallBack(inMessage);
        }
        return "";
    }
  

  复制@Override
    public String scanQRCodesCallBack(WxMpXmlMessage message) {
        log.info("总的message：" + JSON.toJSONString(message));
        // content 公众号回复用户的文本内容
        String content = "欢迎关注公众号！NatCross是内网穿透工具,也是免费的端口映射软件。解决80被封/动态IP/无公网ip问题；适用于发布网站、访问局域网服务器和应用服务。";
        String messageType = message.getMsgType();                                //消息类型
        String messageEvent = message.getEvent();                                    //消息事件
        String fromUser = message.getFromUser();                                 //发送者帐号
        String toUser = message.getToUser();                                       //开发者微信号
        String text = message.getContent();                                        //文本消息  文本内容
        String eventKey = message.getEventKey();                                    //二维码参数
        JSONObject businessParams = JSON.parseObject(eventKey);                    //从二维码参数中获取uuid通过该uuid可通过websocket前端传数据
  
        log.info("消息类型:{},消息事件:{},发送者账号:{},接收者微信:{},文本消息:{},二维码参数：{}", messageType, messageEvent, fromUser, toUser, text, eventKey);
        WxMpUser wxMpUser = null;
        try {
            wxMpUser = wxMpService.getUserService().userInfo(fromUser);
        } catch (WxErrorException e) {
            e.printStackTrace();
        }
        log.info("通过用户openid获取用户信息：" + JSON.toJSONString(wxMpUser));
        if (StringUtils.equalsAnyIgnoreCase(WechatEventEnum.unsubscribe.getType(), messageEvent)) {
            //取消订阅
            log.info("取消订阅");
            return this.msgStr(message, "取消关注成功！");
        }
        String uuid = businessParams.containsKey("uuid") ? businessParams.getString("uuid") : null;
        if (StringUtils.isEmpty(uuid)) {
            //未知关注公众号，默认提示
            log.info("未知关注公众号，默认提示");
            return this.msgStr(message, content);
        }
        String redisData = Objects.toString(stringRedisTemplate.opsForValue().get(RedisKey.WECHAT_SCAN_UUID_FLAG + uuid), null);
        if (StringUtils.isNotEmpty(redisData) && wxMpUser != null) {
            if (StringUtils.equalsAnyIgnoreCase(WechatEventEnum.SCAN.getType(), messageEvent)) {
                String eventType = businessParams.getString("eventType");
                if (StringUtils.equalsAnyIgnoreCase(MsgEventTypeEnum.ADD_WARNING_RECEIVER.getEventType(), eventType)) {
                    content = DateUtils.dateTimeNow(DateUtils.YYYY_MM_DD_HH_MM_SS) + "添加告警接收人成功！";
                } else if (StringUtils.equalsAnyIgnoreCase(MsgEventTypeEnum.USER_LOGIN.getEventType(), eventType)) {
                    content = DateUtils.dateTimeNow(DateUtils.YYYY_MM_DD_HH_MM_SS) + "扫描登录成功！";
                }
                JSONObject dataMap = JSON.parseObject(redisData);
                dataMap.put("openid", wxMpUser.getOpenId());
                dataMap.put("unionid", wxMpUser.getUnionId());
                dataMap.put("nickName", wxMpUser.getNickname());
                dataMap.put("headImgUrl", wxMpUser.getHeadImgUrl());
                stringRedisTemplate.opsForValue().set(RedisKey.WECHAT_SCAN_UUID_RESULT_FLAG + uuid, dataMap.toString());
            }
        }
        // 根据来时的信息格式，重组返回。(注意中间不能有空格)
        final String msgStr = this.msgStr(message, content);
        return msgStr;
    }
  
    @Override
    public NatMemberWechat getScanResult(String uuid) {
        String redisData = Objects.toString(stringRedisTemplate.opsForValue().get(RedisKey.WECHAT_SCAN_UUID_RESULT_FLAG + uuid), null);
        if (StringUtils.isEmpty(redisData)) {
            log.debug("redisData is null");
            return null;
        }
        JSONObject jsonObject = JSONObject.parseObject(redisData);
        NatMemberWechat natMemberWechat = natMemberWechatService.selectNatMemberWechatByOpenId(jsonObject.getString("openid"));
        if(natMemberWechat==null){
            natMemberWechat=new NatMemberWechat();
            natMemberWechat.setOpenId(jsonObject.getString("openid"));
            natMemberWechat.setUserId(null);
        }
        return natMemberWechat;
    }
  
    private String msgStr(WxMpXmlMessage message, String content) {
        // 根据来时的信息格式，重组返回。(注意中间不能有空格)
        final String msgStr = "<xml>"
                + "<ToUserName><![CDATA[" + message.getFromUser() + "]]></ToUserName>"
                + "<FromUserName><![CDATA[" + message.getToUser() + "]]></FromUserName>"
                + "<CreateTime>" + new Date().getTime() + "</CreateTime>"
                + "<MsgType><![CDATA[text]]></MsgType>"
                + "<Content><![CDATA[" + content + "]]></Content>"
                + "</xml>";
        return msgStr;
    }
  

• 回调日志​​​​​​​测试通过后，如果是vue前后端分离，可以把接口给前端调用。
  以上是JAVA实现公众号扫码登录和关注的开发流程。