//首先工具类
public class MyX509TrustManager implements X509TrustManager {
    @Override
    public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
    }
    @Override
    public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
    }
    @Override
    public X509Certificate[] getAcceptedIssuers() {
        return new X509Certificate[0];
    }
}

//WeixinUtil工具类 获取token需要用到的
public class WeixinUtil {
    private static Logger log = LoggerFactory.getLogger(WeixinUtil.class);
    /**
     * 发起https请求并获取结果
     *
     * @param requestUrl 请求地址
     * @param requestMethod 请求方式（GET、POST）
     * @param outputStr 提交的数据
     * @return JSONObject(通过JSONObject.get(key)的方式获取json对象的属性值)
     */
    public static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
        JSONObject jsonObject = null;
        StringBuffer buffer = new StringBuffer();
        try {
            // 创建SSLContext对象，并使用我们指定的信任管理器初始化
            TrustManager[] tm = { new MyX509TrustManager() };
            SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
            sslContext.init(null, tm, new java.security.SecureRandom());
            // 从上述SSLContext对象中得到SSLSocketFactory对象
            SSLSocketFactory ssf = sslContext.getSocketFactory();

            URL url = new URL(requestUrl);
            HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();
            httpUrlConn.setSSLSocketFactory(ssf);

            httpUrlConn.setDoOutput(true);
            httpUrlConn.setDoInput(true);
            httpUrlConn.setUseCaches(false);
            // 设置请求方式（GET/POST）
            httpUrlConn.setRequestMethod(requestMethod);
            if ("GET".equalsIgnoreCase(requestMethod))
                httpUrlConn.connect();
            // 当有数据需要提交时
            if (null != outputStr) {
                OutputStream outputStream = httpUrlConn.getOutputStream();
                // 注意编码格式，防止中文乱码
                outputStream.write(outputStr.getBytes("UTF-8"));
                outputStream.close();
            }
            // 将返回的输入流转换成字符串
            InputStream inputStream = httpUrlConn.getInputStream();
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
            String str = null;
            while ((str = bufferedReader.readLine()) != null) {
                buffer.append(str);
            }
            bufferedReader.close();
            inputStreamReader.close();
            // 释放资源
            inputStream.close();
            inputStream = null;
            httpUrlConn.disconnect();
            jsonObject = JSONObject.parseObject(buffer.toString());
        } catch (ConnectException ce) {
            log.error("Weixin server connection timed out.");
        } catch (Exception e) {
            log.error("https request error:{}", e);
        }
        return jsonObject;
    }
}

//AccessToken
public class AccessToken {
    // 获取到的凭证
    private String token;
    // 凭证有效时间，单位：秒
    private int expiresIn;
    public String getToken() {
        return token;
    }
    public void setToken(String token) {
        this.token = token;
    }
    public int getExpiresIn() {
        return expiresIn;
    }
    public void setExpiresIn(int expiresIn) {
        this.expiresIn = expiresIn;
    }
}

//在获取小程序码之前，首先获取token
public String getToken(){
        Locale locale = new Locale("en", "US");
        ResourceBundle resource = ResourceBundle.getBundle("你的配置文件路径", locale);   //读取属性文件
        String appId = resource.getString("appId"); //开发者设置中的appId
        String secret = resource.getString("appSecret"); //开发者设置中的appSecret
        AccessToken accessToken = null;
        ////请求地址 https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET
        String requestUrl = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" + appId + "&secret=" + secret;
        JSONObject jsonObject = WeixinUtil.httpRequest(requestUrl, "GET", null);
        // 如果请求成功
        if (null != jsonObject) {
            try {
                accessToken = new AccessToken();
                accessToken.setToken(jsonObject.getString("access_token"));
                accessToken.setExpiresIn(jsonObject.getIntValue("expires_in"));
            } catch (JSONException e) {
                accessToken = null;
                // 获取token失败
                logger.error("获取token失败 errcode:{} errmsg:{}", jsonObject.getIntValue("errcode"), jsonObject.getString("errmsg"));
            }
        }
String token = accessToken.getToken();
return token;
}

//下面在获取小程序码
    public Map getQrCode(String accessToken) {
        RestTemplate rest = new RestTemplate();
        InputStream inputStream = null;
        OutputStream outputStream = null;
        try {
            String url = "https://api.weixin.qq.com/wxa/getwxacode?access_token=" + accessToken;
            Map<String, Object> param = new HashMap<>();
          //param.put("path", "pages/要跳转小程序的路径")//有限
          //param.put("page", "pages/index/index"); //无限
            param.put("width", 430);
            param.put("auto_color", false);
            Map<String, Object> line_color = new HashMap<>();
            line_color.put("r", 0);
            line_color.put("g", 0);
            line_color.put("b", 0);
            param.put("line_color", line_color);
            logger.info("调用生成微信URL接口传参:" + param);
            MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
            HttpEntity requestEntity = new HttpEntity(JSON.toJSONString(param), headers);
            ResponseEntity<byte[]> entity = rest.exchange(url, HttpMethod.POST, requestEntity, byte[].class, new Object[0]);
            logger.info("调用小程序生成微信永久小程序码URL接口返回结果:" + entity.getBody());
            byte[] result = entity.getBody();
            logger.info(Base64.encodeBase64String(result));
            inputStream = new ByteArrayInputStream(result);

            File file = new File("保存到本地的路径");
            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) {
            logger.error("调用小程序生成微信永久小程序码URL接口异常", e);
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }