微信公众号关注回调

环境：

1、springboot后端服务

我们可以在用户关注运营的微信公众号后获取微信的用户信息，并将其存入自己的库中，以便后期使用，申请公众号的步骤这里就不涉猎了，具体操作如下：

1、在公众号页面配置服务器回调地址，只能是域名且是80或者443端口

2、在后端服务中提供这个接口，修改完成后点击下面的“提交”按钮，成功回调后后续用户关注取消关注时都会回调这个接口，本文给一个示例接口：

@RequestMapping(value = "/xxx/onWxMsg")
    public String checkWxToken(@RequestParam(value = "signature", required = false) String signature,
                               @RequestParam(value = "timestamp", required = false) String timestamp,
                               @RequestParam(value = "echostr", required = false) String echostr,
                               @RequestBody(required = false) WxServiceMsgDto wxServiceMsgDto) {
        if (StringUtils.isNotEmpty(echostr)) {
           // 用于微信校验接口存在性，必须返回echostr
            return echostr;
        }
        // 只处理订阅与取消订阅消息
        if (null != wxServiceMsgDto && StringUtils.isNotEmpty(wxServiceMsgDto.getMsgType()) &&
                StringUtils.isNotEmpty(wxServiceMsgDto.getEvent())) {
            String msgType = wxServiceMsgDto.getMsgType();
            String event = wxServiceMsgDto.getEvent();
            boolean isSubcribe = WxMessageType.EVENT.getCode().equals(msgType) &&
                    (WxEeventType.SUBSCRIBE.getCode().equals(event)
                            || WxEeventType.UNSUBSCRIBE.getCode().equals(event));
            if (isSubcribe) {
                WxEeventType wxEeventType = WxEeventType.SUBSCRIBE.getCode().equals(event) ? WxEeventType.SUBSCRIBE : WxEeventType.UNSUBSCRIBE;
                wxService.onFollowCallback(wxServiceMsgDto, wxEeventType);
            }
        }
   。。。。。。
}

　　核心类定义如下：

@XmlRootElement(name = "xml")
@XmlAccessorType(XmlAccessType.FIELD)
@Data
public class WxServiceMsgDto {
  
     @XmlElement(name = "Event")
     private String event;
  
     @XmlElement(name = "Content")
     private String content;
  
     @XmlElement(name = "MsgType")
     private String msgType;
  
     @XmlElement(name = "ToUserName")
     private String toUserName;
  
      
     /**
      * fromUserName为关注人的openId
     **/
  
     @XmlElement(name = "FromUserName")
     private String fromUserName;
  
     @XmlElement(name="CreateTime")
     private String createTime;
}

@Getter
public enum WxEeventType {
    /**
     * 关注公众号
     */
    SUBSCRIBE("subscribe"),
    /**
     * 取消关注公众号
     */
    UNSUBSCRIBE("unsubscribe");
  
    private String code;
  
    WxEeventType(String code) {
        this.code = code;
    }
}

@Getter
public enum WxMessageType {
  
    /**
     * 事件类型，比如订阅与取消订阅
     */
    EVENT("event"),
    /**
     * 向公众号发送的文字消息
     */
    TEXT("text");
  
    private String code;
  
    WxMessageType(String code) {
        this.code = code;
    }
}