blocks|key|293124|text|你的帖子来自不同的来源(所以不同的端口或主机名)吗？如果是这样的话，我刚刚回答的这个最近的话题可能会有所帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|293125|293126|Odd+jQuery+problem+-+Ajax+request+to+a+C+program+not+quite+working|unordered-list-item|offset|length|293127|293128|问题出在XHR跨域策略，以及如何使用一种称为JSONP的技术绕过它的有用技巧。最大的缺点是JSONP不支持POST请求。|293129|我知道在最初的帖子中没有提到JavaScript，但是JSON通常用于JavaScript，所以这就是我跳到这个结论的原因|293130|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/3831255/odd-jquery-problem-ajax-request-to-a-c-program-not-quite-working^0|0|0|0|1U|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|V|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|W|8|@]|9|@$F|X|G|Y|1|Z]]|A|$]]|$1|H|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

Are you posting from a different source (so different port, or hostname)? If so, this very very recent topic I just answered might be helpful.

<ul>
<li><a href="https://stackoverflow.com/questions/3831255/odd-jquery-problem-ajax-request-to-a-c-program-not-quite-working">Odd jQuery problem - Ajax request to a C program not quite working</a></li>
</ul>

The problem was the XHR Cross Domain Policy, and a useful tip on how to get around it by using a technique called JSONP. The big downside is that JSONP does not support POST requests.

I know in the original post there is no mention of JavaScript, however JSON is usually used for JavaScript so that's why I jumped to that conclusion

blocks|key|3019460|text|通常，您可以通过相同的方式在servlet中获取和发布参数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3019461|request.getParameter("cmd");|code-block|syntax|javascript|3019462|，但仅当POST数据是以键值对形式的内容类型的应用程序时：“/x-www-++-urlencoded”，就像使用标准HTML表单时一样。|offset|length|style|BOLD|3019463|如果您对post数据使用不同的编码模式，就像您在post+json数据流时一样，您需要使用一个自定义解码器来处理来自以下内容的原始数据流：|3019464|BufferedReader+reader+=+request.getReader();|3019465|Json后处理示例(使用++包)|3019466|public+void+doPost(HttpServletRequest+request,+HttpServletResponse+response)
++throws+ServletException,+IOException+{

++StringBuffer+jb+=+new+StringBuffer();
++String+line+=+null;
++try+{
++++BufferedReader+reader+=+request.getReader();
++++while+((line+=+reader.readLine())+!=+null)
++++++jb.append(line);
++}+catch+(Exception+e)+{+/*report+an+error*/+}

++try+{
++++JSONObject+jsonObject+=++HTTP.toJSONObject(jb.toString());
++}+catch+(JSONException+e)+{
++++//+crash+and+burn
++++throw+new+IOException("Error+parsing+JSON+request+string");
++}

++//+Work+with+the+data+using+methods+like...
++//+int+someInt+=+jsonObject.getInt("intParamName");
++//+String+someString+=+jsonObject.getString("stringParamName");
++//+JSONObject+nestedObj+=+jsonObject.getJSONObject("nestedObjName");
++//+JSONArray+arr+=+jsonObject.getJSONArray("arrayParamName");
++//+etc...
}|3019467|entityMap^0|0|0|0|U|0|0|0|0|C|E|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@$I|14|J|15|K|L]|$I|16|J|17|K|L]]|9|@]|A|$]]|$1|S|3|T|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|U|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|V|$]]

Normaly you can GET and POST parameters in a servlet the same way:

<pre><code>request.getParameter("cmd");
</code></pre>

But only if the POST data is <a href="http://en.wikipedia.org/wiki/POST_(HTTP)">encoded</a> as key-value pairs of content type: "application/x-www-form-urlencoded" like when you use a standard HTML form.

If you use a different encoding schema for your post data, as in your case when you post a json data stream, you need to use a custom decoder that can process the raw datastream from:

<pre><code>BufferedReader reader = request.getReader();
</code></pre>

Json post processing example (uses <a href="http://www.json.org/">org.json</a> package )

<pre><code>public void doPost(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {

 StringBuffer jb = new StringBuffer();
 String line = null;
 try {
 BufferedReader reader = request.getReader();
 while ((line = reader.readLine()) != null)
 jb.append(line);
 } catch (Exception e) { /*report an error*/ }

 try {
 JSONObject jsonObject = HTTP.toJSONObject(jb.toString());
 } catch (JSONException e) {
 // crash and burn
 throw new IOException("Error parsing JSON request string");
 }

 // Work with the data using methods like...
 // int someInt = jsonObject.getInt("intParamName");
 // String someString = jsonObject.getString("stringParamName");
 // JSONObject nestedObj = jsonObject.getJSONObject("nestedObjName");
 // JSONArray arr = jsonObject.getJSONArray("arrayParamName");
 // etc...
}
</code></pre>

I am HTTP POST-ing to URL http://laptop:8080/apollo/services/rpc?cmd=execute
with
POST data
<pre class="lang-json prettyprint-override"><code>{ &quot;jsondata&quot; : &quot;data&quot; }
</code></pre>
Http request has Content-Type of <code>application/json; charset=UTF-8</code>
How do I get the POST data (jsondata) from HttpServletRequest?
If I enumerate the request params, I can only see one param,
which is &quot;cmd&quot;, not the POST data.

HttpServletRequest get JSON POST data

数据流

JSON

我是HTTP POST-ing to URL 使用POST数据{ "jsondata" : "data" }Http请求的Content-Type为application/json; charset=UTF-8如何从HttpServletRequest获取POST数据(jsondata)？如果我枚举请求参数，我只能看到...

问HttpServletRequest获取JSON POST数据
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