手写一个生成带参数 微信二维码的工具类

1.先定义接口

package com.example.mongodemo.framework.wechat;

import com.example.mongodemo.framework.wechat.entity.AccessToken;
import com.example.mongodemo.framework.wechat.entity.ImageTicket;
import com.example.mongodemo.framework.wechat.entity.LoginUser;
import org.checkerframework.checker.signature.qual.FieldDescriptorForPrimitive;

/**
 * @Author lyr
 * @create 2020/4/19 15:54
 */
public interface WechatTemplate {
    /**
     * 获取token的 url，没什么用
     * @return 生成获取 token的 url
     */
    @Deprecated
    String generateTokenUrl();

    /**
     * 请求微信接口，获取 accessToken
     * @return 返回微信的 ACCESS_TOKEN
     */
    AccessToken getAccessTokenObject();

    /**
     * 查看用户的登录状态
     * @param sceneId 场景id
     * @return 返回登录状态的包装类
     */
    LoginUser isUserLogin(String sceneId);

    /**
     * 查看用户是否登录，后台确认登录了，返回true，否则返回 false
     * @param sceneId 用户场景id
     * @return
     */
    boolean userIsLogin(String sceneId);

    /**
     * 设置用户已经登录
     * @param sceneId 用户场景id => 表示唯一的用户
     */
    void setUserIsLogin(String sceneId);

    /**
     * 获取扫描二维码的图片门票
     * @return 获取扫码二维码的图片门票
     */
    ImageTicket getImageTicket();

    /**
     * 生成访问二维码的 url
     * @param ticket 门票对象
     * @return
     */
    String generateQrCodeUrl(ImageTicket ticket);
}

下面是 AccesToken 的 pojo 等等

package com.example.mongodemo.framework.wechat.entity;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;

/**
 * @Author lyr
 * @create 2020/4/19 13:50
 */
@Data
public class AccessToken {
    /**
     * redis前缀
     */
    public static final String REDIS_KEY = "ac_tk::actk";

    @JsonProperty("access_token")
    private String accessTokenContent;
    @JsonProperty("expires_in")
    private Long expiresIn;
}

// 生成二维码的门票

package com.example.mongodemo.framework.wechat.entity;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;
import lombok.experimental.Accessors;

/**
 * @Author lyr
 * @create 2020/4/19 16:00
 * 获取微信二维码的门票
 *
 */
@Data
@Accessors(chain = true)
public class ImageTicket {

    /**
     * 获取微信二维码门票的链接
     */
    public static final String
    GET_TICKET_URL = "https://api.weixin.qq.com/cgi-bin/qrcode/create?" +
            "access_token=" +
            "%s";



    /**
     * 获取微信二维码的门票
     */
    @JsonProperty("ticket")
    private String ticket;

    /**
     * 过期时间
     */
    @JsonProperty("expires_seconds")
    private Integer expireSeconds;
    /**
     * 返回给前端，让前端用这个 sceneId 轮询后端接口，确认是否用户已经登录
     */
    private String sceneId;

}

用户登录状态实体（这里其实不用看的，你要什么业务，定义什么接口）

package com.example.mongodemo.framework.wechat.entity;

import com.example.mongodemo.pojo.WeixinUserInfo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.RequiredArgsConstructor;
import lombok.experimental.Accessors;

/**
 * @Author lyr
 * @create 2020/4/19 15:29
 */
@Data
@Accessors(chain = true)
@AllArgsConstructor
public class LoginUser {
    public static final String REDIS_KEY=
            "loginuser::";

    private String sceneId;


    /**
     * 登录状态
     */
    private Boolean loginStatus = false;

    public LoginUser(String sceneId) {
        this.sceneId = sceneId;
    }
}

请求接口，获取门票的配置

package com.example.mongodemo.framework.wechat.entity;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.Data;
import lombok.experimental.Accessors;

/**
 * @Author lyr
 * @create 2020/4/19 16:20
 */
@Data
@Accessors(chain = true)
public class TicketRequest {

    public static final
    String REQUEST_TICKET_URL
            ="https://api.weixin.qq.com/cgi-bin/qrcode/create?" +
            "access_token=" +
            "%s"
    ;
    public static final String REQUEST_TEMPLATE
            ="{\n" +
            "    \"expire_seconds\": 1800,\n" +
            "    \"action_name\": \"QR_SCENE\",\n" +
            "    \"action_info\": {\n" +
            "        \"scene\": {\n" +
            "            \"scene_str\": \"%s\"\n" +
            "        }\n" +
            "    }\n" +
            "}";



}

wechatTemplate 的实现

package com.example.mongodemo.framework.wechat;

import com.example.mongodemo.framework.wechat.entity.AccessToken;
import com.example.mongodemo.framework.wechat.entity.ImageTicket;
import com.example.mongodemo.framework.wechat.entity.LoginUser;
import com.example.mongodemo.framework.wechat.entity.TicketRequest;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;


import javax.annotation.Resource;
import java.time.Duration;

/**
 * @Author lyr
 * @create 2020/4/19 11:31
 */
@Component
@Slf4j
public class RestWechatTemplate implements WechatTemplate{
    /**
     * 获取 调用接口权限 的 ac token
     */
    @Value("${wechatTemplate.getTicket.appid}")
    private String appId;
    /**
     * **
     */
    @Value("${wechatTemplate.getTicket.secret}")
    private String secret;
    @Value("${wechatTemplate.getTicket.grant_type}")
    private String grantType;
    @Resource
    private RedisTemplate<String, Object> redisTemplate;
    /**
     * 远程调用 微信接口
     */
    @Resource
    private RestTemplate restTemplate;

    /**
     * @return 生成请求微信接口的 url => 请求 微信token的 url
     */
    @Override
    public String generateTokenUrl() {
        String getBasicAccessToken = "https://api.weixin.qq.com/cgi-bin/" +
                "token?" +
                "grant_type=%s" +
                "&" +
                "appid=%s" +
                "&" +
                "secret=%s";
        return String.format(getBasicAccessToken,grantType,appId,secret);

        // //log.info("微信返回结果 {}",responseString);
        // return responseString;
    }





    /**
     * 公众号每日 10000 次调用机会
     * @return 返回 AccessToken
     */
    @Deprecated
    public String getAccessToken() {
        String responseString
                = restTemplate
                .getForObject(generateTokenUrl(),String.class);
        return responseString;
    }

    /**
     * @return 请求微信接口，获得 AccessToken =》将 json传转对象
     */
    @Override
    public AccessToken getAccessTokenObject() {
        AccessToken token = (AccessToken) redisTemplate.opsForValue()
                .get(AccessToken.REDIS_KEY);
        if(token==null) {
            //请求微信
            token = restTemplate.getForObject(generateTokenUrl(),AccessToken.class);

            if(token!=null) {
                //缓存 token 至有效时间
                redisTemplate.opsForValue()
                        .set(AccessToken.REDIS_KEY,token, Duration.ofSeconds(token.getExpiresIn()-10));
            }

        }
        return token;
    }


    /**
     * 用户是否已经登录
     * @param sceneId 场景id
     * @return
     */
    @Override
    public LoginUser isUserLogin(String sceneId) {
        LoginUser loginUser = (LoginUser) redisTemplate
                .opsForValue()
                .get(LoginUser.REDIS_KEY);
        return loginUser==null ? new LoginUser(sceneId):loginUser;
    }

    /**
     * 用户是否已经登录
     * @param sceneId 场景id
     * @return
     */
    @Override
    public boolean userIsLogin(String sceneId) {
        return isUserLogin(sceneId).getLoginStatus();
    }

    @Override
    public void setUserIsLogin(String sceneId) {
        redisTemplate.opsForValue()
                .set(LoginUser.REDIS_KEY+sceneId,new LoginUser(sceneId).setLoginStatus(true));
    }

    @Override
    public ImageTicket getImageTicket() {
        String getTicketUrl = String
                .format(ImageTicket.GET_TICKET_URL,
                        getAccessTokenObject()
                                .getAccessTokenContent());
        String sceneId
                = String.valueOf(System.nanoTime());
        ResponseEntity<ImageTicket> responseEntity = restTemplate
                .postForEntity(
                        //url
                        getTicketUrl,
                        //请求参数
                        String.format(TicketRequest.REQUEST_TEMPLATE, sceneId),
                        ImageTicket.class
                );

        ImageTicket ticket = responseEntity.getBody();

        return ticket!=null?ticket.setSceneId(sceneId):null;
    }
    @Override
    public String generateQrCodeUrl(ImageTicket ticket) {
        String qrCodeUrl = "https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=%s";
        return String.format(qrCodeUrl, ticket.getTicket());
    }







}