先要去微信公众平台注册一个小程序，每个小程序都有相应的AppID(小程序ID)和AppSecret(小程序密钥)，它们是获取ACCESS_TOKEN所需要的。微信公众平台地址：

https://mp.weixin.qq.com/

注册添加小程序后会取得AppID(小程序ID)和AppSecret(小程序密钥)：

* 需要正确的 appid 和 secret 查看自己的微信开放平台 */ public String getAccessToken() { //这里需要换成你d的小程序appid String appid = "wx141ac029d803ce4c"; //这里需要换成你的小程序secret String appSecret = "bb245ef5f0add972bccd718087b7dd50"; //获取微信ACCESS_TOKEN 的Url String accent_token_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET"; String url = accent_token_url.replace("APPID", appid).replace("APPSECRET", appSecret); //发送请求 String result = HttpClientUtils.doGet(url); Map resultMap = (Map) JsonUtil.jsonToMap(result); System.out.println("access_token------>" + resultMap.get("access_token").toString()); return resultMap.get("access_token").toString(); } } public class HttpClientUtils { private static final Logger LOGGER = LoggerFactory.getLogger(HttpClientUtils.class); private static ConnectionSocketFactory plainsf = null; private static LayeredConnectionSocketFactory sslsf = null; private static Registry registry = null; private static PoolingHttpClientConnectionManager cm = null; private static HttpRequestRetryHandler httpRequestRetryHandler = null; private static RequestConfig requestConfig = null; private static CloseableHttpClient httpClient = null; static { plainsf = PlainConnectionSocketFactory.getSocketFactory(); sslsf = SSLConnectionSocketFactory.getSocketFactory(); registry = RegistryBuilder.create() .register("http", plainsf) .register("https", sslsf) .build(); cm = new PoolingHttpClientConnectionManager(registry); // 最大连接数 cm.setMaxTotal(30); // 每个路由基础的连接 cm.setDefaultMaxPerRoute(10); //请求重试处理 httpRequestRetryHandler = new HttpRequestRetryHandler() { @Override public boolean retryRequest(IOException exception, int executionCount, HttpContext context) { if (executionCount >= 5) {// 如果已经重试了5次，就放弃 return false; } if (exception instanceof NoHttpResponseException) {// 如果服务器丢掉了连接，那么就重试 return true; } if (exception instanceof SSLHandshakeException) {// 不要重试SSL握手异常 return false; } if (exception instanceof InterruptedIOException) {// 超时 return false; } if (exception instanceof UnknownHostException) {// 目标服务器不可达 return false; } if (exception instanceof ConnectTimeoutException) {// 连接被拒绝 return false; } if (exception instanceof SSLException) {// ssl握手异常 return false; } HttpClientContext clientContext = HttpClientContext.adapt(context); HttpRequest request = clientContext.getRequest(); // 如果请求是幂等的，就再次尝试 if (!(request instanceof HttpEntityEnclosingRequest)) { return true; } return false; } }; requestConfig = RequestConfig.custom() .setConnectionRequestTimeout(5000) .setConnectTimeout(5000) .setSocketTimeout(5000) .build(); httpClient = HttpClients.custom() .setConnectionManager(cm) .setRetryHandler(httpRequestRetryHandler) .build(); } /** * get请求 * * @param url 访问ur * @return */ public static String doGet(String url) { String result = null; CloseableHttpResponse response = null; HttpGet httpget = new HttpGet(url); try { String resultEnc = "UTF-8"; httpget.setConfig(requestConfig); response = httpClient.execute(httpget, HttpClientContext.create()); result = EntityUtils.toString(response.getEntity(), resultEnc); } catch (Exception e) { LOGGER.error("get请求 doPost", e); return result; } finally { if (null != response) { try { response.close(); } catch (IOException e) { LOGGER.error("get请求 doPost IOException", e); } } httpget.abort(); } return result; } /** * 获取数据流 * * @param url * @param paraMap * @return */ public static byte[] doImgPost(String url, Map paraMap) { byte[] result = null; HttpPost httpPost = new HttpPost(url); httpPost.addHeader("Content-Type", "application/json"); try { // 设置请求的参数 JSONObject postData = new JSONObject(); for (Map.Entry entry : paraMap.entrySet()) { postData.put(entry.getKey(), entry.getValue()); } httpPost.setEntity(new StringEntity(postData.toString(), "UTF-8")); HttpClient httpClient = HttpClientBuilder.create().build(); HttpResponse response = httpClient.execute(httpPost); HttpEntity entity = response.getEntity(); result = EntityUtils.toByteArray(entity); } catch (ConnectionPoolTimeoutException e) { e.printStackTrace(); } catch (ConnectTimeoutException e) { e.printStackTrace(); } catch (SocketTimeoutException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } finally { httpPost.releaseConnection(); } return result; } } public class JsonUtil { private static Gson gson = new Gson(); public static Map jsonToMap(String jsonStr) { Map objMap = null; if (gson != null) { Type type = new com.google.gson.reflect.TypeToken