Java 如何实现POST(x-www-form-urlencoded)请求

<dependency>
    <groupId>commons-httpclient</groupId>
    <artifactId>commons-httpclient</artifactId>
    <version>3.1</version>
</dependency>

try {
    String postURL
    PostMethod postMethod = null;
    postMethod = new PostMethod(postURL) ;
    postMethod.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=utf-8") ;
//参数设置，需要注意的就是里边不能传NULL，要传空字符串
    NameValuePair[] data = {
            new NameValuePair("startTime",""),
            new NameValuePair("endTime","")            
    };
    postMethod.setRequestBody(data);
    org.apache.commons.httpclient.HttpClient httpClient = new org.apache.commons.httpclient.HttpClient();
    int response = httpClient.executeMethod(postMethod); // 执行POST方法
    String result = postMethod.getResponseBodyAsString() ;
    return result;
} catch (Exception e) {
    logger.info("请求异常"+e.getMessage(),e);
    throw new RuntimeException(e.getMessage());
}

public String getMsg() {
    String result = "";
    try {
        URL url = new URL("https://XXXX.cn/token");
        //通过调用url.openConnection()来获得一个新的URLConnection对象，并且将其结果强制转换为HttpURLConnection.
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestMethod("POST");
        //设置连接的超时值为30000毫秒，超时将抛出SocketTimeoutException异常
        urlConnection.setConnectTimeout(30000);
        //设置读取的超时值为30000毫秒，超时将抛出SocketTimeoutException异常
        urlConnection.setReadTimeout(30000);
        //将url连接用于输出，这样才能使用getOutputStream()。getOutputStream()返回的输出流用于传输数据
        urlConnection.setDoOutput(true);
        //设置通用请求属性为默认浏览器编码类型
        urlConnection.setRequestProperty("content-type", "application/x-www-form-urlencoded");
        //getOutputStream()返回的输出流，用于写入参数数据。
        OutputStream outputStream = urlConnection.getOutputStream();
        String content = "grant_type=password&app_key="+APP_KEY+"&app_secret="+APP_SECRET;
        outputStream.write(content.getBytes());
        outputStream.flush();
        outputStream.close();
        //此时将调用接口方法。getInputStream()返回的输入流可以读取返回的数据。
        InputStream inputStream = urlConnection.getInputStream();
        byte[] data = new byte[1024];
        StringBuilder sb = new StringBuilder();
        //inputStream每次就会将读取1024个byte到data中，当inputSteam中没有数据时，inputStream.read(data)值为-1
        while (inputStream.read(data) != -1) {
            String s = new String(data, Charset.forName("utf-8"));
            sb.append(s);
        }
        result = sb.toString();
        inputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return result;
}