使用post发送接口请求

urlString ：接口请求地址
params：参数
encode：编码

 public static String post(String urlString, Map<String, String> params,
            String encode) throws Exception {
        PostMethod method = new PostMethod(urlString);
        try {
            Set<String> keys = params.keySet();
            NameValuePair[] values = new NameValuePair[keys.size()];
            int i = 0;
            for (String key : keys) {
                NameValuePair v = new NameValuePair();
                v.setName(key);
                v.setValue(params.get(key));
                values[i] = v;
                i++;
            }

            HttpClient client = new HttpClient();
            client.getHostConfiguration().setHost(urlString, 80, "http");
            if (!"".equals(encode) && encode != null)
                client.getParams().setParameter(
                        HttpMethodParams.HTTP_CONTENT_CHARSET, encode);
            method.setRequestBody(values); // 使用 POST 方式提交数据
            int state = client.executeMethod(method); // 返回的状态
            if (state != HttpStatus.SC_OK) {
                throw new Exception("HttpStatus is " + state);
            }
            String response = method.getResponseBodyAsString();
            if (null != encode && !StringUtils.EMPTY.equals(encode)) {// nul写在前面，避免空指针
                response = new String(response.getBytes(encode), encode);
            }
            return response; // response就是最后得到的结果
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        } finally {
            method.releaseConnection();
        }
    }