RestTemplate 调用外部方法

 /**
     * 定义调用外部接口实例
     */
    private static final RestTemplate INSTANCE = new RestTemplate();

    public static RestTemplate getInstance() {
        return HttpRequestService.INSTANCE;
    }

    /**
     * @param uri          uri
     * @param param        请求参数
     * @param responseType 返回值类型
     * @param <T>
     * @return
     */
    public <T> T request(String uri, String param, Class<T> responseType) {
        // 设置请求头信息
        HttpHeaders headers = new HttpHeaders();
        MediaType type = MediaType.parseMediaType("application/json; charset=UTF-8");
        headers.setContentType(type);
        headers.add("Accept-Charset", MediaType.APPLICATION_JSON.toString());
        // 封装参数
        HttpEntity<String> object = new HttpEntity<>(param, headers);
        String url = YTX_URL + uri;
        LOGGER.info("request url:{},appkey:{},ts:{},msgdgt:{}", url, appKey, ts, msgdgt);
        ResponseEntity<T> exchange = getInstance().exchange(url, HttpMethod.DELETE, object, responseType);
        LOGGER.info("responseResult code:{},body:{}", exchange.getStatusCode(), exchange.getBody());
        return exchange.getBody();
    }