API请求签名加密，备注

public static void main(String[] args) {
try {
// params 请求参数
Map<String, String> params = new HashMap<String, String>();
params.put("username", "test");
params.put("password", "test");

        String queryString = "";

        for (Map.Entry<String, String> entry : params.entrySet()) {
            queryString += "&" + entry.getKey() + "=" + entry.getValue();
        }
        if (queryString.length() > 0) {
            queryString = queryString.substring(1);
        }

        // 获取请求body长度
        int contentlength = queryString.getBytes().length;
        // 接口校验账户信息
        String api_key = "10000";
        String api_pass = "poiuytrewq1234567890";

        // 请求的接口
        String url = "http://127.0.0.1/api/2/login.dhtml";
        // 请求事件
        long date = System.currentTimeMillis();
        // 生成签名
        StringBuffer sign = new StringBuffer();
        sign.append(HttpMethod.POST);
        sign.append(url);
        sign.append(date);
        sign.append(contentlength);
        sign.append(api_pass);
        String md5Sign = MD5.toMD5(sign.toString());
        // 将请求事件和请求签名添加到header当中
        Map<String, String> headers = new HashMap<String, String>();
        headers.put("date", date + "");
        headers.put("sign", api_key + ":" + md5Sign);
        // 封装http body请求体
        HttpRequestBody body = new HttpRequestBody(url, charSet, HttpMethod.POST, headers, null, params);
        HttpClient client = new HttpClient();
        HttpResponseBody response = client.service(body);
        // http请求返回状态
        System.out.println(response.getCode());
        // http请求返回结果
        System.out.println(response.getResultString());
    } catch (HttpErrorException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

服务端获取后校验