发送一个post请求apache和java

Question

我有这个代码块，它向我的一个localhost端口发送一个post请求：

public String request(String name){
        String responseString = null;

        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("userName", name));
        params.add(new BasicNameValuePair("passWord","123455"));
        HttpPost post = new HttpPost("http://localhost:2332/getData/postData");
        post.addHeader("Content-Type", "application/x-www-form-urlencoded");
        post.setEntity(new StringEntity(URLEncodedUtils.format(params,"UTF-8"), HTTP.UTF_8));

        responseString = execute(post,params.toString());

        return responseString;
    }

    public String execute(HttpRequestBase requestBase, String params){
        HttpClient httpClient = new DefaultHttpClient();
        HttpResponse response = null;
        String responseString = "";
        try {
            LOG.info("Request Method:{}",requestBase.getMethod());
            LOG.info("Request Parameters:{}",params);

            response = httpClient.execute(requestBase);
            HttpEntity entity = response.getEntity();
            responseString = EntityUtils.toString(entity);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return responseString;
    }

我认为这个代码块应该可以工作，因为我使用了一个教程作为参考，但每当我运行我的应用程序时，responseString的值为null或者应用程序没有向我显示任何结果。我的代码有问题吗？