我也有同样的问题。我想通过POST发送数据。 我使用了以下代码:

    URL url = new URL("http://example.com/getval.php");
    Map<String,Object> params = new LinkedHashMap<>();
    params.put("param1", param1);
    params.put("param2", param2);

    StringBuilder postData = new StringBuilder();
    for (Map.Entry<String,Object> param : params.entrySet()) {
        if (postData.length() != 0) postData.append('&');
        postData.append(URLEncoder.encode(param.getKey(), "UTF-8"));
        postData.append('=');
        postData.append(URLEncoder.encode(String.valueOf(param.getValue()), "UTF-8"));
    }
    String urlParameters = postData.toString();
    URLConnection conn = url.openConnection();

    conn.setDoOutput(true);

    OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());

    writer.write(urlParameters);
    writer.flush();

    String result = "";
    String line;
    BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

    while ((line = reader.readLine()) != null) {
        result += line;
    }
    writer.close();
    reader.close()
    System.out.println(result);

我使用Jsoup进行解析:

    Document doc = Jsoup.parseBodyFragment(value);
    Iterator<Element> opts = doc.select("option").iterator();
    for (;opts.hasNext();) {
        Element item = opts.next();
        if (item.hasAttr("value")) {
            System.out.println(item.attr("value"));
        }
    }

我发现HttpURLConnection使用起来非常麻烦。你必须写大量样板，容易出错的代码。我需要一个轻量级的包装为我的Android项目，并提出了一个库，你可以使用:DavidWebb。

上面的例子可以这样写:

Webb webb = Webb.create();
webb.post("http://example.com/index.php")
        .param("param1", "a")
        .param("param2", "b")
        .param("param3", "c")
        .ensureSuccess()
        .asVoid();

您可以在提供的链接上找到备选库的列表。

我用Boann的答案创建了一个更灵活的查询字符串构建器，支持列表和数组，就像php的http_build_query方法一样:

public static byte[] httpBuildQueryString(Map<String, Object> postsData) throws UnsupportedEncodingException {
    StringBuilder postData = new StringBuilder();
    for (Map.Entry<String,Object> param : postsData.entrySet()) {
        if (postData.length() != 0) postData.append('&');

        Object value = param.getValue();
        String key = param.getKey();

        if(value instanceof Object[] || value instanceof List<?>)
        {
            int size = value instanceof Object[] ? ((Object[])value).length : ((List<?>)value).size();
            for(int i = 0; i < size; i++)
            {
                Object val = value instanceof Object[] ? ((Object[])value)[i] : ((List<?>)value).get(i);
                if(i>0) postData.append('&');
                postData.append(URLEncoder.encode(key + "[" + i + "]", "UTF-8"));
                postData.append('=');            
                postData.append(URLEncoder.encode(String.valueOf(val), "UTF-8"));
            }
        }
        else
        {
            postData.append(URLEncoder.encode(key, "UTF-8"));
            postData.append('=');            
            postData.append(URLEncoder.encode(String.valueOf(value), "UTF-8"));
        }
    }
    return postData.toString().getBytes("UTF-8");
}

我强烈推荐构建在apache http api上的http-request。

对于你的案例，你可以看到例子:

private static final HttpRequest<String.class> HTTP_REQUEST = 
      HttpRequestBuilder.createPost("http://example.com/index.php", String.class)
           .responseDeserializer(ResponseDeserializer.ignorableDeserializer())
           .build();

public void sendRequest(String request){
     String parameters = request.split("\\?")[1];
     ResponseHandler<String> responseHandler = 
            HTTP_REQUEST.executeWithQuery(parameters);

   System.out.println(responseHandler.getStatusCode());
   System.out.println(responseHandler.get()); //prints response body
}

如果您对响应体不感兴趣

private static final HttpRequest<?> HTTP_REQUEST = 
     HttpRequestBuilder.createPost("http://example.com/index.php").build();

public void sendRequest(String request){
     ResponseHandler<String> responseHandler = 
           HTTP_REQUEST.executeWithQuery(parameters);
}

对于一般发送post请求与HTTP -request:阅读文档，看到我的答案HTTP post请求与JSON字符串在JAVA，发送HTTP post请求在JAVA, HTTP post使用JSON在JAVA

似乎你还必须调用connection. getoutputstream ()"至少一次"(以及setDoOutput(true))，以将其视为POST。

所以最低要求的代码是:

    URL url = new URL(urlString);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    //connection.setRequestMethod("POST"); this doesn't seem to do anything at all..so not useful
    connection.setDoOutput(true); // set it to POST...not enough by itself however, also need the getOutputStream call...
    connection.connect();
    connection.getOutputStream().close(); 

令人惊讶的是，你甚至可以在urlString中使用“GET”样式参数。尽管这可能会让事情变得复杂。

显然，你也可以使用NameValuePair。

我看到一些其他的答案给出了另一种选择，我个人认为直觉上你在做正确的事情;)不好意思，在devoxx上，有几个演讲者一直在抱怨这种事情。

这就是为什么我个人使用Apache的HTTPClient/HttpCore库来做这类工作，我发现它们的API比Java的原生HTTP支持更容易使用。当然是YMMV了!