生成微信小程序指定页面二维码

首先官方开发文档参考：https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/qr-code/wxacode.createQRCode.html

生成的二维码类型有两种：

1：永久有效，但有数量限制  

POST https://api.weixin.qq.com/cgi-bin/wxaapp/createwxaqrcode?access_token=ACCESS_TOKEN

POST https://api.weixin.qq.com/wxa/getwxacode?access_token=ACCESS_TOKEN

 

2：永久有效，但无数量限制

POST https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=ACCESS_TOKEN

我这边用的是第二个，首先需要获得ACCESS_TOKEN

public String token(String appid,String secret) throws IOException {
    id = 2L;
    CloseableHttpClient httpClient = HttpClients.createDefault();
    String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="+ appid +"&secret="+secret;
    HttpPost post = new HttpPost(url);
    CloseableHttpResponse response =httpClient.execute(post);
    String string = EntityUtils.toString(response.getEntity());
    System.out.println(string);
    response.close();
    httpClient.close();
    return string;
}

 

第二步就是调用接口了

public String QR(String access_token) throws IOException {   
   int count = 0;//双引号个数
//字符串处理，截取这边不做json转换，当然你可以拿去自己改成自己想用的
   for (int i = 0; i < string.length(); i++) {
       String s = string.substring(i, i + 1);
       if ("\"".equals(s)) {
           count++;
       }
   }
   List list = new ArrayList();
   for (int i = 0; i < count; i = i + 2) {
       string = string.substring(string.indexOf("\"") + 1, string.length());
       String strTemp = string.substring(0, string.indexOf("\""));
       string = string.substring(strTemp.length() + 1);
       list.add(strTemp);
   }
   String access_token = list.get(1);
   RestTemplate rest = new RestTemplate();
   InputStream inputStream = null;
   OutputStream outputStream = null;
   Long sceneStr = null;//传入的参数
   try {
       String url1 = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token="+ access_token;
       Map param = new HashMap<>();
       param.put("page", "pages/unit/unit");跳转的页面
       param.put("scene", sceneStr);
       param.put("width", 430);
       param.put("auto_color", true);
       param.put("is_hyaline", true);
       MultiValueMap headers = new LinkedMultiValueMap<>();
       HttpEntity requestEntity = new HttpEntity(param, headers);
       ResponseEntity entity = rest.exchange(url1, HttpMethod.POST, requestEntity, byte[].class, new    Object[0]);
       byte[] result = entity.getBody();
       inputStream = new ByteArrayInputStream(result);
       UUID uuid = UUID.randomUUID();
       String filePathName = fileProperties.QRFilePath + uuid + ".png";//文件存储路径
       File file = new File(filePathName);
       if (!file.exists()){
           file.createNewFile();
       }
       outputStream = new FileOutputStream(file);
       int len = 0;
       byte[] buf = new byte[1024];
       while ((len = inputStream.read(buf, 0, 1024)) != -1) {
           outputStream.write(buf, 0, len);
       }
       outputStream.flush();
   } catch (Exception e) {
       e.getMessage();
   } finally {
       if(inputStream != null){
           try {
               inputStream.close();
           } catch (IOException e) {
               e.printStackTrace();
           }
       }

       if(outputStream != null){
           try {
               outputStream.close();
           } catch (IOException e) {
               e.printStackTrace();
           }
       }
   }
   return filePathName;
}