通过微信小程序获取二维码的方式有三种, 这里总结一下生成无限制的小程序二维码

调用方式

上代码

1. 定义一个存放接口信息的对象

public String getAccessToken() {
          
   
        String accessToken = (String) redisService.get("ACCESS_TOKEN");
        if (accessToken == null) {
          
   
            String url = WechatInterface.GET_ACCESS_TOKEN_URL
                    .replace("APPID", wechatProperties.getAppid())
                    .replace("APPSECRET", wechatProperties.getAppSecret());
            String         body           = HttpClientUtils.doGet(url);
            AccessTokenDto accessTokenDto = gson.fromJson(body, AccessTokenDto.class);
            accessToken = accessTokenDto.getAccessToken();
            redisService.set("ACCESS_TOKEN", accessToken);
            redisService.expire("ACCESS_TOKEN", 120);
        }
        return accessToken;
    }

public String getQrCode(Long orderId) throws ExecutionException, InterruptedException, IOException {
          
   
        String accessToken = getAccessToken();
        String url = WechatInterface.UNLIMITED_QR_CODE
                .replace("ACCESS_TOKEN", accessToken);
        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("page", wechatProperties.getQrCodePath());
        paramMap.put("scene", "orderId=" + orderId);
        paramMap.put("env_version", wechatProperties.getEnvVersion());
        return getBase64FromInputStream(HttpClientUtils.doPost(url, gson.toJson(paramMap)));
    }

4. 上面的HttpClientUtils用的是java11的HttpClient, 随便做了一点封装, 大家有更好的也可以用自己的

static HttpClient client = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .connectTimeout(Duration.ofMillis(5000))
            .followRedirects(HttpClient.Redirect.NORMAL)
            .build();
            
	public static InputStream doPost(String url, String requestBody) {
          
   
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                //指定提交表单的方式编码请求体
                .header("Contend-Type", "application/json")
                //通过字符串创建请求体，然后作为POST请求的请求参数
                .POST(HttpRequest.BodyPublishers.ofString(requestBody))
                .build();
        HttpResponse<InputStream> response;
        try {
          
   
            response = client.send(request, HttpResponse.BodyHandlers.ofInputStream());
        } catch (IOException | InterruptedException e) {
          
   
            throw new RuntimeException(e);
        }
        return response.body();
    }

5. 最后请求接口, 返回base64, 完事