public static String getAccessToken(String appid, String appsecret)
    {
        String requestUrl = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="+appid+"&secret="+appsecret+"";
        String accessToken = null;
        try
        {
            String response = HttpClientUtil.getInstance().sendHttpsGet(
                    requestUrl, null);
            JSONObject json = JSONObject.parseObject(response);
            accessToken = String.valueOf(json.get("access_token"));
        }
        catch (Exception e)
        {
            logger.error("getAccessToken error", e);
        }

        return accessToken;
    }

說(shuō)明：調(diào)用微信API接口傳入小程序的appid和appsecret參數(shù)即可。

調(diào)用微信api生成小程序太陽(yáng)碼

 public static String generatLimitSunCode(WxScanCodeParam param) throws Exception 
    {
       String token =param.getAccessToken();
       Map<String, String> params = new HashMap<>();
       params.put("path", param.getPath());
       params.put("width", "430");
       CloseableHttpClient httpClient = HttpClientBuilder.create().build();
       HttpPost httpPost = new HttpPost("https://api.weixin.qq.com/wxa/getwxacode?access_token="+token);
       httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
       String body = JSON.toJSONString(params);
       StringEntity entity = new StringEntity(body);
       entity.setContentType("image/jpg");
       httpPost.setEntity(entity);
       HttpResponse response = httpClient.execute(httpPost);
       int statusCode = response.getStatusLine().getStatusCode();
       if (statusCode == HttpStatus.SC_OK) 
       {
           HttpEntity entity2 = response.getEntity();
           if(!entity2.getContentType().getValue().equals("image/jpeg"))
           {
               String result = EntityUtils.toString(entity2, "UTF-8");
               logger.error("generate sun code error,http execute result:" + result);
               return null;
           }
       }
       else
       {
           logger.error("generate sun code error,http execute result:" + statusCode);
       }
       
       InputStream inputStream = response.getEntity().getContent();
        // 保存圖片到本地     
       int flag = saveImg(inputStream, param.getFilePath(), name);
       if (flag == 0)
       {
           throw new SysException("保存圖片[" + name + "]失敗");
       }
       else
       {
           logger.info("太陽(yáng)碼[{}]生成成功", name);
       }
       return param.getFilePath() + File.separatorChar + name;
   }

說(shuō)明

參數(shù)說(shuō)明

path：掃碼進(jìn)入的小程序頁(yè)面路徑，最大長(zhǎng)度 128 字節(jié)，不能為空；例如:pages/index/index
access_token：小程序授權(quán)token

注意事項(xiàng)

需要特殊注意,本方案生成的小程序太陽(yáng)碼與二維碼的總數(shù)不能超過(guò)10萬(wàn)個(gè)，微信沒(méi)有提供對(duì)應(yīng)的Api接口查詢的使用的數(shù)量，一旦超過(guò)了數(shù)量，將會(huì)導(dǎo)致小程序失效，且微信目前無(wú)法重置查詢次數(shù)，適合于生成數(shù)量少的場(chǎng)景。

生成無(wú)限制太陽(yáng)碼

獲取小程序的access_token

如同第一種的方案

調(diào)用微信api生成小程序太陽(yáng)碼

/**
     * 生成無(wú)限制的小程序碼
     * @param param
     * @return
     * @throws Exception
     */
    public static String generatUnlimitSunCode(WxScanCodeParam param) throws Exception 
    {
       String token =param.getAccessToken();
       Map<String, String> params = new HashMap<>();
       params.put("scene", param.getScene());
       params.put("page", param.getPath());
       params.put("width", "430");
       CloseableHttpClient httpClient = HttpClientBuilder.create().build();
       HttpPost httpPost = new HttpPost("https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token="+token);
       httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
       String body = JSON.toJSONString(params);
       StringEntity entity = new StringEntity(body);
       entity.setContentType("image/jpg");
       httpPost.setEntity(entity);
       HttpResponse response = httpClient.execute(httpPost);
       int statusCode = response.getStatusLine().getStatusCode();
       if (statusCode == HttpStatus.SC_OK) 
       {
           HttpEntity entity2 = response.getEntity();
           if(!entity2.getContentType().getValue().equals("image/jpeg"))
           {
               String result = EntityUtils.toString(entity2, "UTF-8");
               logger.error("generate sun code error,http execute result:" + result);
               return null;
           }
       }
       else
       {
           logger.error("generate sun code error,http execute result:" + statusCode);
       }
       
       InputStream inputStream = response.getEntity().getContent();
       
       //太陽(yáng)碼寫標(biāo)題
       String content=param.getWriteContent();
       if(StringUtil.isNotEmpty(content) && param.isWrite())
       {
          inputStream = ImageUtil.addImageTitle(param.getWriteContent(), inputStream, 450, 450);
       }
      
       String name = param.getFileName()+".jpg";//文件名加后綴，跟上面對(duì)應(yīng)
       

       int flag = saveImg(inputStream, param.getFilePath(), name);// 保存圖片
       if (flag == 0)
       {
           throw new SysException("保存圖片[" + name + "]失敗");
       }
       else
       {
           logger.info("太陽(yáng)碼[{}]生成成功", name);
       }
       return param.getFilePath() + File.separatorChar + name;
   }

說(shuō)明

參數(shù)說(shuō)明

scene：最大32個(gè)可見(jiàn)字符,參數(shù)格式可以自行定義a&b或者a=1&b=2都行
access_token：小程序授權(quán)token

參數(shù)過(guò)長(zhǎng)問(wèn)題

由于scene參數(shù)的長(zhǎng)度只支持32位字符，如果參數(shù)超過(guò)了32位，我們將如何合處理？

解決方案

改問(wèn)題的解決方案為：設(shè)計(jì)一張小程序參數(shù)表，將生成的參數(shù)存儲(chǔ)到表中，生成小程序是scene參數(shù)設(shè)置此表表的主鍵，小程序掃碼后，先請(qǐng)求后臺(tái)通過(guò)scene參數(shù)獲取小程序的具體參數(shù)。

如下示例：