blocks|key|1650586|text|调用HttpURLConnection.setRequestMethod("POST")和HttpURLConnection.setDoOutput(true);实际上只需要后者作为POST，然后成为默认方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1650587|entityMap^0|2|16|19|10|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

Call <code>HttpURLConnection.setRequestMethod("POST")</code> and <code>HttpURLConnection.setDoOutput(true);</code> Actually only the latter is needed as POST then becomes the default method.

blocks|key|1444801|text|String+rawData+=+"id=10";
String+type+=+"application/x-www-form-urlencoded";
String+encodedData+=+URLEncoder.encode(+rawData,+"UTF-8"+);+
URL+u+=+new+URL("http://www.example.com/page.php");
HttpURLConnection+conn+=+(HttpURLConnection)+u.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty(+"Content-Type",+type+);
conn.setRequestProperty(+"Content-Length",+String.valueOf(encodedData.length()));
OutputStream+os+=+conn.getOutputStream();
os.write(encodedData.getBytes());|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1444802|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>String rawData = "id=10";
String type = "application/x-www-form-urlencoded";
String encodedData = URLEncoder.encode( rawData, "UTF-8" ); 
URL u = new URL("http://www.example.com/page.php");
HttpURLConnection conn = (HttpURLConnection) u.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty( "Content-Type", type );
conn.setRequestProperty( "Content-Length", String.valueOf(encodedData.length()));
OutputStream os = conn.getOutputStream();
os.write(encodedData.getBytes());
</code></pre>

blocks|key|1650607|text|更新答案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1650608|由于原始答案中的一些类在较新版本的Apache+HTTP组件中已被弃用，因此我在此发布此更新。|1650609|顺便说一句，您可以访问更多示例here的完整文档。|offset|length|1650610|HttpClient+httpclient+=+HttpClients.createDefault();
HttpPost+httppost+=+new+HttpPost("http://www.a-domain.com/foo/");

//+Request+parameters+and+other+properties.
List<NameValuePair>+params+=+new+ArrayList<NameValuePair>(2);
params.add(new+BasicNameValuePair("param-1",+"12345"));
params.add(new+BasicNameValuePair("param-2",+"Hello!"));
httppost.setEntity(new+UrlEncodedFormEntity(params,+"UTF-8"));

//Execute+and+get+the+response.
HttpResponse+response+=+httpclient.execute(httppost);
HttpEntity+entity+=+response.getEntity();

if+(entity+!=+null)+{
++++try+(InputStream+instream+=+entity.getContent())+{
++++++++//+do+something+useful
++++}
}|code-block|syntax|javascript|1650611|原始答案：|1650612|我推荐使用Apache+HttpClient。它更快、更容易实现。|1650613|HttpPost+post+=+new+HttpPost("http://jakarata.apache.org/");
NameValuePair[]+data+=+{
++++new+NameValuePair("user",+"joe"),
++++new+NameValuePair("password",+"bloggs")
};
post.setRequestBody(data);
//+execute+method+and+handle+any+error+responses.
...
InputStream+in+=+post.getResponseBodyAsStream();
//+handle+response.|1650614|有关更多信息，请查看此url：http://hc.apache.org/|1650615|entityMap|0|LINK|mutability|MUTABLE|url|http://hc.apache.org/httpcomponents-client-ga/tutorial/html/fundamentals.html#d5e37|1|http://hc.apache.org/^0|0|0|F|4|0|0|0|0|0|0|F|L|1|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|16|8|@]|9|@$F|17|G|18|1|19]]|A|$]]|$1|H|3|I|5|J|7|1A|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|1B|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Q|3|R|5|J|7|1D|8|@]|9|@]|A|$K|L]]|$1|S|3|T|5|6|7|1E|8|@]|9|@$F|1F|G|1G|1|1H]]|A|$]]|$1|U|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]|12|$5|X|Y|Z|A|$10|13]]]]

<h3>Updated Answer:</h3>

Since some of the classes, in the original answer, are deprecated in the newer version of Apache HTTP Components, I'm posting this update.

By the way, you can access the full documentation for more examples <a href="http://hc.apache.org/httpcomponents-client-ga/tutorial/html/fundamentals.html#d5e37" rel="noreferrer">here</a>.

<pre><code>HttpClient httpclient = HttpClients.createDefault();
HttpPost httppost = new HttpPost("http://www.a-domain.com/foo/");

// Request parameters and other properties.
List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;(2);
params.add(new BasicNameValuePair("param-1", "12345"));
params.add(new BasicNameValuePair("param-2", "Hello!"));
httppost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));

//Execute and get the response.
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();

if (entity != null) {
 try (InputStream instream = entity.getContent()) {
 // do something useful
 }
}
</code></pre>

<h3>Original Answer:</h3>

I recommend to use Apache HttpClient. its faster and easier to implement.

<pre><code>HttpPost post = new HttpPost("http://jakarata.apache.org/");
NameValuePair[] data = {
 new NameValuePair("user", "joe"),
 new NameValuePair("password", "bloggs")
};
post.setRequestBody(data);
// execute method and handle any error responses.
...
InputStream in = post.getResponseBodyAsStream();
// handle response.
</code></pre>

for more information check this url: <a href="http://hc.apache.org/" rel="noreferrer">http://hc.apache.org/</a>

blocks|key|1444829|text|第一个答案很好，但我必须添加try/catch以避免Java编译器错误。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1444830|此外，我也很难理解如何使用Java库来读取HttpResponse。|offset|length|style|CODE|1444831|下面是更完整的代码：|1444832|/*
+*+Create+the+POST+request
+*/
HttpClient+httpClient+=+new+DefaultHttpClient();
HttpPost+httpPost+=+new+HttpPost("http://example.com/");
//+Request+parameters+and+other+properties.
List<NameValuePair>+params+=+new+ArrayList<NameValuePair>();
params.add(new+BasicNameValuePair("user",+"Bob"));
try+{
++++httpPost.setEntity(new+UrlEncodedFormEntity(params,+"UTF-8"));
}+catch+(UnsupportedEncodingException+e)+{
++++//+writing+error+to+Log
++++e.printStackTrace();
}
/*
+*+Execute+the+HTTP+Request
+*/
try+{
++++HttpResponse+response+=+httpClient.execute(httpPost);
++++HttpEntity+respEntity+=+response.getEntity();

++++if+(respEntity+!=+null)+{
++++++++//+EntityUtils+to+get+the+response+content
++++++++String+content+=++EntityUtils.toString(respEntity);
++++}
}+catch+(ClientProtocolException+e)+{
++++//+writing+exception+to+log
++++e.printStackTrace();
}+catch+(IOException+e)+{
++++//+writing+exception+to+log
++++e.printStackTrace();
}|code-block|syntax|javascript|1444833|entityMap^0|0|L|C|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@$D|S|E|T|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|U|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|V|8|@]|9|@]|A|$M|N]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The first answer was great, but I had to add try/catch to avoid Java compiler errors. 
Also, I had troubles to figure how to read the <code>HttpResponse</code> with Java libraries. 

Here is the more complete code :

<pre><code>/*
 * Create the POST request
 */
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("http://example.com/");
// Request parameters and other properties.
List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;();
params.add(new BasicNameValuePair("user", "Bob"));
try {
 httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
} catch (UnsupportedEncodingException e) {
 // writing error to Log
 e.printStackTrace();
}
/*
 * Execute the HTTP Request
 */
try {
 HttpResponse response = httpClient.execute(httpPost);
 HttpEntity respEntity = response.getEntity();

 if (respEntity != null) {
 // EntityUtils to get the response content
 String content = EntityUtils.toString(respEntity);
 }
} catch (ClientProtocolException e) {
 // writing exception to log
 e.printStackTrace();
} catch (IOException e) {
 // writing exception to log
 e.printStackTrace();
}
</code></pre>

blocks|key|5179858|text|使用Apache+HTTP组件的一种简单方法是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5179859|Request.Post("http://www.example.com/page.php")
++++++++++++.bodyForm(Form.form().add("id",+"10").build())
++++++++++++.execute()
++++++++++++.returnContent();|code-block|syntax|javascript|5179860|看一看Fluent+API|offset|length|5179861|entityMap|0|LINK|mutability|MUTABLE|url|http://hc.apache.org/httpcomponents-client-5.0.x^0|0|0|3|A|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

A simple way using Apache HTTP Components is
<pre><code>Request.Post(&quot;http://www.example.com/page.php&quot;)
 .bodyForm(Form.form().add(&quot;id&quot;, &quot;10&quot;).build())
 .execute()
 .returnContent();
</code></pre>
Take a look at the <a href="http://hc.apache.org/httpcomponents-client-5.0.x" rel="nofollow noreferrer">Fluent API</a>

blocks|key|3762026|text|在vanilla+Java中，发送POST请求很容易。从URL开始，我们需要使用url.openConnection();将其转换为URLConnection。之后，我们需要将它转换为HttpURLConnection，这样我们就可以访问它的setRequestMethod()方法来设置我们的方法。最后，我们说我们将通过连接发送数据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3762027|URL+url+=+new+URL("https://www.example.com/login");
URLConnection+con+=+url.openConnection();
HttpURLConnection+http+=+(HttpURLConnection)con;
http.setRequestMethod("POST");+//+PUT+is+another+valid+option
http.setDoOutput(true);|code-block|syntax|javascript|3762028|然后我们需要说明我们要发送的内容：|3762029|发送一个简单的表单|3762030|来自http表单的普通POST具有well+defined格式。我们需要将输入转换为以下格式：|3762031|Map<String,String>+arguments+=+new+HashMap<>();
arguments.put("username",+"root");
arguments.put("password",+"sjh76HSn!");+//+This+is+a+fake+password+obviously
StringJoiner+sj+=+new+StringJoiner("&");
for(Map.Entry<String,String>+entry+:+arguments.entrySet())
++++sj.add(URLEncoder.encode(entry.getKey(),+"UTF-8")+%2B+"="+
+++++++++%2B+URLEncoder.encode(entry.getValue(),+"UTF-8"));
byte[]+out+=+sj.toString().getBytes(StandardCharsets.UTF_8);
int+length+=+out.length;|3762032|然后，我们可以将表单内容附加到具有适当标头的http请求并发送它。|3762033|http.setFixedLengthStreamingMode(length);
http.setRequestProperty("Content-Type",+"application/x-www-form-urlencoded;+charset=UTF-8");
http.connect();
try(OutputStream+os+=+http.getOutputStream())+{
++++os.write(out);
}
//+Do+something+with+http.getInputStream()|3762034|3762035|发送JSON|3762036|我们也可以使用java发送json，这也很简单：|3762037|byte[]+out+=+"{\"username\":\"root\",\"password\":\"password\"}"+.getBytes(StandardCharsets.UTF_8);
int+length+=+out.length;

http.setFixedLengthStreamingMode(length);
http.setRequestProperty("Content-Type",+"application/json;+charset=UTF-8");
http.connect();
try(OutputStream+os+=+http.getOutputStream())+{
++++os.write(out);
}
//+Do+something+with+http.getInputStream()|3762038|请记住，不同的服务器接受不同的json内容类型，请参阅this问题。|3762039|3762040|使用java+post发送文件|3762041|发送文件可以被认为是更具挑战性的处理，因为格式更复杂。我们还将添加对以字符串形式发送文件的支持，因为我们不希望将文件完全缓冲到内存中。|3762042|为此，我们定义了一些助手方法：|3762043|private+void+sendFile(OutputStream+out,+String+name,+InputStream+in,+String+fileName)+{
++++String+o+=+"Content-Disposition:+form-data;+name=\""+%2B+URLEncoder.encode(name,"UTF-8")+
+++++++++++++%2B+"\";+filename=\""+%2B+URLEncoder.encode(filename,"UTF-8")+%2B+"\"\r\n\r\n";
++++out.write(o.getBytes(StandardCharsets.UTF_8));
++++byte[]+buffer+=+new+byte[2048];
++++for+(int+n+=+0;+n+>=+0;+n+=+in.read(buffer))
++++++++out.write(buffer,+0,+n);
++++out.write("\r\n".getBytes(StandardCharsets.UTF_8));
}

private+void+sendField(OutputStream+out,+String+name,+String+field)+{
++++String+o+=+"Content-Disposition:+form-data;+name=\""+
+++++++++++++%2B+URLEncoder.encode(name,"UTF-8")+%2B+"\"\r\n\r\n";
++++out.write(o.getBytes(StandardCharsets.UTF_8));
++++out.write(URLEncoder.encode(field,"UTF-8").getBytes(StandardCharsets.UTF_8));
++++out.write("\r\n".getBytes(StandardCharsets.UTF_8));
}|3762044|然后我们可以使用这些方法来创建一个多部分的post请求，如下所示：|3762045|String+boundary+=+UUID.randomUUID().toString();
byte[]+boundaryBytes+=+
+++++++++++("--"+%2B+boundary+%2B+"\r\n").getBytes(StandardCharsets.UTF_8);
byte[]+finishBoundaryBytes+=+
+++++++++++("--"+%2B+boundary+%2B+"--").getBytes(StandardCharsets.UTF_8);
http.setRequestProperty("Content-Type",+
+++++++++++"multipart/form-data;+charset=UTF-8;+boundary="+%2B+boundary);

//+Enable+streaming+mode+with+default+settings
http.setChunkedStreamingMode(0);+

//+Send+our+fields:
try(OutputStream+out+=+http.getOutputStream())+{
++++//+Send+our+header+(thx+Algoman)
++++out.write(boundaryBytes);

++++//+Send+our+first+field
++++sendField(out,+"username",+"root");

++++//+Send+a+seperator
++++out.write(boundaryBytes);

++++//+Send+our+second+field
++++sendField(out,+"password",+"toor");

++++//+Send+another+seperator
++++out.write(boundaryBytes);

++++//+Send+our+file
++++try(InputStream+file+=+new+FileInputStream("test.txt"))+{
++++++++sendFile(out,+"identification",+file,+"text.txt");
++++}

++++//+Finish+the+request
++++out.write(finishBoundaryBytes);
}


//+Do+something+with+http.getInputStream()|3762046|entityMap|0|LINK|mutability|MUTABLE|url|https://www.rfc-editor.org/rfc/rfc1866#section-8.2.1|1|https://stackoverflow.com/q/477816/1542723^0|S|3|14|L|1U|D|2K|H|3D|I|0|0|0|0|H|C|0|0|0|0|0|0|0|0|0|R|4|1|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1S|8|@$9|1T|A|1U|B|C]|$9|1V|A|1W|B|C]|$9|1X|A|1Y|B|C]|$9|1Z|A|20|B|C]|$9|21|A|22|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|23|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|24|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|25|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|26|8|@]|D|@$9|27|A|28|1|29]]|E|$]]|$1|Q|3|R|5|H|7|2A|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|2B|8|@]|D|@]|E|$]]|$1|U|3|V|5|H|7|2C|8|@]|D|@]|E|$I|J]]|$1|W|3|-4|5|6|7|2D|8|@]|D|@]|E|$]]|$1|X|3|Y|5|6|7|2E|8|@]|D|@]|E|$]]|$1|Z|3|10|5|6|7|2F|8|@]|D|@]|E|$]]|$1|11|3|12|5|H|7|2G|8|@]|D|@]|E|$I|J]]|$1|13|3|14|5|6|7|2H|8|@]|D|@$9|2I|A|2J|1|2K]]|E|$]]|$1|15|3|-4|5|6|7|2L|8|@]|D|@]|E|$]]|$1|16|3|17|5|6|7|2M|8|@]|D|@]|E|$]]|$1|18|3|19|5|6|7|2N|8|@]|D|@]|E|$]]|$1|1A|3|1B|5|6|7|2O|8|@]|D|@]|E|$]]|$1|1C|3|1D|5|H|7|2P|8|@]|D|@]|E|$I|J]]|$1|1E|3|1F|5|6|7|2Q|8|@]|D|@]|E|$]]|$1|1G|3|1H|5|H|7|2R|8|@]|D|@]|E|$I|J]]|$1|1I|3|-4|5|6|7|2S|8|@]|D|@]|E|$]]]|1J|$1K|$5|1L|1M|1N|E|$1O|1P]]|1Q|$5|1L|1M|1N|E|$1O|1R]]]]

Sending a POST request is easy in vanilla Java. Starting with a <code>URL</code>, we need t convert it to a <code>URLConnection</code> using <code>url.openConnection();</code>. After that, we need to cast it to a <code>HttpURLConnection</code>, so we can access its <code>setRequestMethod()</code> method to set our method. We finally say that we are going to send data over the connection.
<pre class="lang-java prettyprint-override"><code>URL url = new URL(&quot;https://www.example.com/login&quot;);
URLConnection con = url.openConnection();
HttpURLConnection http = (HttpURLConnection)con;
http.setRequestMethod(&quot;POST&quot;); // PUT is another valid option
http.setDoOutput(true);
</code></pre>
We then need to state what we are going to send:
<h2>Sending a simple form</h2>
A normal POST coming from a http form has a <a href="https://www.rfc-editor.org/rfc/rfc1866#section-8.2.1" rel="nofollow noreferrer">well defined</a> format. We need to convert our input to this format:
<pre class="lang-java prettyprint-override"><code>Map&lt;String,String&gt; arguments = new HashMap&lt;&gt;();
arguments.put(&quot;username&quot;, &quot;root&quot;);
arguments.put(&quot;password&quot;, &quot;sjh76HSn!&quot;); // This is a fake password obviously
StringJoiner sj = new StringJoiner(&quot;&amp;&quot;);
for(Map.Entry&lt;String,String&gt; entry : arguments.entrySet())
 sj.add(URLEncoder.encode(entry.getKey(), &quot;UTF-8&quot;) + &quot;=&quot; 
 + URLEncoder.encode(entry.getValue(), &quot;UTF-8&quot;));
byte[] out = sj.toString().getBytes(StandardCharsets.UTF_8);
int length = out.length;
</code></pre>
We can then attach our form contents to the http request with proper headers and send it.
<pre class="lang-java prettyprint-override"><code>http.setFixedLengthStreamingMode(length);
http.setRequestProperty(&quot;Content-Type&quot;, &quot;application/x-www-form-urlencoded; charset=UTF-8&quot;);
http.connect();
try(OutputStream os = http.getOutputStream()) {
 os.write(out);
}
// Do something with http.getInputStream()
</code></pre>
<hr />
<h2>Sending JSON</h2>
We can also send json using java, this is also easy:
<pre class="lang-java prettyprint-override"><code>byte[] out = &quot;{\&quot;username\&quot;:\&quot;root\&quot;,\&quot;password\&quot;:\&quot;password\&quot;}&quot; .getBytes(StandardCharsets.UTF_8);
int length = out.length;

http.setFixedLengthStreamingMode(length);
http.setRequestProperty(&quot;Content-Type&quot;, &quot;application/json; charset=UTF-8&quot;);
http.connect();
try(OutputStream os = http.getOutputStream()) {
 os.write(out);
}
// Do something with http.getInputStream()
</code></pre>
Remember that different servers accept different content-types for json, see <a href="https://stackoverflow.com/q/477816/1542723">this</a> question.
<hr />
<h2>Sending files with java post</h2>
Sending files can be considered more challenging to handle as the format is more complex. We are also going to add support for sending the files as a string, since we don't want to buffer the file fully into the memory.
For this, we define some helper methods:
<pre class="lang-java prettyprint-override"><code>private void sendFile(OutputStream out, String name, InputStream in, String fileName) {
 String o = &quot;Content-Disposition: form-data; name=\&quot;&quot; + URLEncoder.encode(name,&quot;UTF-8&quot;) 
 + &quot;\&quot;; filename=\&quot;&quot; + URLEncoder.encode(filename,&quot;UTF-8&quot;) + &quot;\&quot;\r\n\r\n&quot;;
 out.write(o.getBytes(StandardCharsets.UTF_8));
 byte[] buffer = new byte[2048];
 for (int n = 0; n &gt;= 0; n = in.read(buffer))
 out.write(buffer, 0, n);
 out.write(&quot;\r\n&quot;.getBytes(StandardCharsets.UTF_8));
}

private void sendField(OutputStream out, String name, String field) {
 String o = &quot;Content-Disposition: form-data; name=\&quot;&quot; 
 + URLEncoder.encode(name,&quot;UTF-8&quot;) + &quot;\&quot;\r\n\r\n&quot;;
 out.write(o.getBytes(StandardCharsets.UTF_8));
 out.write(URLEncoder.encode(field,&quot;UTF-8&quot;).getBytes(StandardCharsets.UTF_8));
 out.write(&quot;\r\n&quot;.getBytes(StandardCharsets.UTF_8));
}
</code></pre>
We can then use these methods to create a multipart post request as follows:
<pre class="lang-java prettyprint-override"><code>String boundary = UUID.randomUUID().toString();
byte[] boundaryBytes = 
 (&quot;--&quot; + boundary + &quot;\r\n&quot;).getBytes(StandardCharsets.UTF_8);
byte[] finishBoundaryBytes = 
 (&quot;--&quot; + boundary + &quot;--&quot;).getBytes(StandardCharsets.UTF_8);
http.setRequestProperty(&quot;Content-Type&quot;, 
 &quot;multipart/form-data; charset=UTF-8; boundary=&quot; + boundary);

// Enable streaming mode with default settings
http.setChunkedStreamingMode(0); 

// Send our fields:
try(OutputStream out = http.getOutputStream()) {
 // Send our header (thx Algoman)
 out.write(boundaryBytes);

 // Send our first field
 sendField(out, &quot;username&quot;, &quot;root&quot;);

 // Send a seperator
 out.write(boundaryBytes);

 // Send our second field
 sendField(out, &quot;password&quot;, &quot;toor&quot;);

 // Send another seperator
 out.write(boundaryBytes);

 // Send our file
 try(InputStream file = new FileInputStream(&quot;test.txt&quot;)) {
 sendFile(out, &quot;identification&quot;, file, &quot;text.txt&quot;);
 }

 // Finish the request
 out.write(finishBoundaryBytes);
}


// Do something with http.getInputStream()
</code></pre>

blocks|key|1448997|text|使用post请求发送参数的最简单方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1448998|String+postURL+=+"http://www.example.com/page.php";

HttpPost+post+=+new+HttpPost(postURL);

List<NameValuePair>+params+=+new+ArrayList<NameValuePair>();
params.add(new+BasicNameValuePair("id",+"10"));

UrlEncodedFormEntity+ent+=+new+UrlEncodedFormEntity(params,+"UTF-8");
post.setEntity(ent);

HttpClient+client+=+new+DefaultHttpClient();
HttpResponse+responsePOST+=+client.execute(post);|code-block|syntax|javascript|1448999|你已经做到了。现在您可以使用responsePOST了。以字符串形式获取返回内容：|offset|length|style|CODE|1449000|BufferedReader+reader+=+new+BufferedReader(new++InputStreamReader(responsePOST.getEntity().getContent()),+2048);

if+(responsePOST+!=+null)+{
++++StringBuilder+sb+=+new+StringBuilder();
++++String+line;
++++while+((line+=+reader.readLine())+!=+null)+{
++++++++System.out.println("+line+:+"+%2B+line);
++++++++sb.append(line);
++++}
++++String+getResponseString+=+"";
++++getResponseString+=+sb.toString();
//use+server+output+getResponseString+as+string+value.
}|1449001|entityMap^0|0|0|E|C|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

simplest way to send parameters with the post request:

<pre><code>String postURL = "http://www.example.com/page.php";

HttpPost post = new HttpPost(postURL);

List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;();
params.add(new BasicNameValuePair("id", "10"));

UrlEncodedFormEntity ent = new UrlEncodedFormEntity(params, "UTF-8");
post.setEntity(ent);

HttpClient client = new DefaultHttpClient();
HttpResponse responsePOST = client.execute(post);
</code></pre>

You have done. now you can use <code>responsePOST</code>.
Get response content as string:

<pre><code>BufferedReader reader = new BufferedReader(new InputStreamReader(responsePOST.getEntity().getContent()), 2048);

if (responsePOST != null) {
 StringBuilder sb = new StringBuilder();
 String line;
 while ((line = reader.readLine()) != null) {
 System.out.println(" line : " + line);
 sb.append(line);
 }
 String getResponseString = "";
 getResponseString = sb.toString();
//use server output getResponseString as string value.
}
</code></pre>

blocks|key|1650734|text|我推荐使用基于apache+http+api构建的http-request。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1650735|HttpRequest<String>+httpRequest+=+HttpRequestBuilder.createPost("http://www.example.com/page.php",+String.class)
.responseDeserializer(ResponseDeserializer.ignorableDeserializer()).build();

public+void+send(){
+++String+response+=+httpRequest.execute("id",+"10").get();
}|code-block|syntax|javascript|1650736|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/jsunsoftware/http-request^0|P|C|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

I recomend use <a href="https://github.com/jsunsoftware/http-request" rel="nofollow noreferrer">http-request</a> built on apache http api.

<pre><code>HttpRequest&lt;String&gt; httpRequest = HttpRequestBuilder.createPost("http://www.example.com/page.php", String.class)
.responseDeserializer(ResponseDeserializer.ignorableDeserializer()).build();

public void send(){
 String response = httpRequest.execute("id", "10").get();
}
</code></pre>

blocks|key|1650796|text|我建议使用Postman来生成请求代码。只需使用Postman发出请求，然后单击代码选项卡：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1650797|​|1650798|📷|atomic|offset|length|1650799|1650800|然后，您将看到以下窗口，以选择您希望您的请求代码使用哪种语言：|1650801|1650802|1650803|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/3ab62e1e9a929118db0b8f5b86577d7b.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/336d792f79d5c55825b8ef4b7c6d543e.png^0|0|0|0|1|0|0|0|0|0|1|1|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@$G|11|H|12|1|13]]|A|$]]|$1|I|3|C|5|6|7|14|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|15|8|@]|9|@]|A|$]]|$1|L|3|E|5|F|7|16|8|@]|9|@$G|17|H|18|1|19]]|A|$]]|$1|M|3|C|5|6|7|1A|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|O|$P|$5|Q|R|S|A|$T|U|V|-4]]|W|$5|Q|R|S|A|$T|X|V|-4]]]]

I suggest using Postman to generate the request code. Simply make the request using Postman then hit the code tab:
<a href="https://i.stack.imgur.com/XFkQE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/XFkQE.png" alt="code tab" /></a>
Then you'll get the following window to choose in which language you want your request code to be:
<a href="https://i.stack.imgur.com/M6v0o.png" rel="noreferrer"><img src="https://i.stack.imgur.com/M6v0o.png" alt="request code generation" /></a>

blocks|key|3762177|text|使用okhttp：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3762178|可以在https://github.com/square/okhttp中找到okhttp的源代码。|offset|length|3762179|如果您正在编写pom项目，请添加此依赖项|3762180|<dependency>
++++++++<groupId>com.squareup.okhttp3</groupId>
++++++++<artifactId>okhttp</artifactId>
++++++++<version>4.2.2</version>
++++</dependency>|code-block|syntax|javascript|3762181|如果不是，只需在互联网上搜索“download+okhttp”。将出现几个结果，您可以在其中下载jar。|3762182|你的代码：|3762183|import+okhttp3.*;
++++++++
import+java.io.IOException;

public+class+ClassName{
++++++++private+void+sendPost()+throws+IOException+{
++++++++
++++++++++++++++//+form+parameters
++++++++++++++++RequestBody+formBody+=+new+FormBody.Builder()
++++++++++++++++++++++++.add("id",+10)
++++++++++++++++++++++++.build();
++++++++
++++++++++++++++Request+request+=+new+Request.Builder()
++++++++++++++++++++++++.url("http://www.example.com/page.php")
++++++++++++++++++++++++.post(formBody)
++++++++++++++++++++++++.build();


++++++++++++++++OkHttpClient+httpClient+=+new+OkHttpClient();
++++++++
++++++++++++++++try+(Response+response+=+httpClient.newCall(request).execute())+{
++++++++
++++++++++++++++++++if+(!response.isSuccessful())+throw+new+IOException("Unexpected+code+"+%2B+response);
++++++++
++++++++++++++++++++//+Get+response+body
++++++++++++++++++++System.out.println(response.body().string());
++++++++++++++++}
++++++++}
++++}|3762184|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/square/okhttp^0|0|3|W|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@$D|12|E|13|1|14]]|A|$]]|$1|F|3|G|5|6|7|15|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|16|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|17|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|J|7|19|8|@]|9|@]|A|$K|L]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

Using okhttp :
Source code for okhttp can be found here <a href="https://github.com/square/okhttp" rel="nofollow noreferrer">https://github.com/square/okhttp</a>.
If you're writing a pom project, add this dependency
<pre><code>&lt;dependency&gt;
 &lt;groupId&gt;com.squareup.okhttp3&lt;/groupId&gt;
 &lt;artifactId&gt;okhttp&lt;/artifactId&gt;
 &lt;version&gt;4.2.2&lt;/version&gt;
 &lt;/dependency&gt;
</code></pre>
If not simply search the internet for 'download okhttp'. Several results will appear where you can download a jar.
your code :
<pre class="lang-java prettyprint-override"><code>import okhttp3.*;
 
import java.io.IOException;

public class ClassName{
 private void sendPost() throws IOException {
 
 // form parameters
 RequestBody formBody = new FormBody.Builder()
 .add(&quot;id&quot;, 10)
 .build();
 
 Request request = new Request.Builder()
 .url(&quot;http://www.example.com/page.php&quot;)
 .post(formBody)
 .build();


 OkHttpClient httpClient = new OkHttpClient();
 
 try (Response response = httpClient.newCall(request).execute()) {
 
 if (!response.isSuccessful()) throw new IOException(&quot;Unexpected code &quot; + response);
 
 // Get response body
 System.out.println(response.body().string());
 }
 }
 }
</code></pre>

blocks|key|5180095|text|轻松使用java.net：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5180096|public+void+post(String+uri,+String+data)+throws+Exception+{
HttpClient+client+=+HttpClient.newBuilder().build();
HttpRequest+request+=+HttpRequest.newBuilder()
++++++++.uri(URI.create(uri))
++++++++.POST(BodyPublishers.ofString(data))
++++++++.build();

HttpResponse<?>+response+=+client.send(request,+BodyHandlers.discarding());
System.out.println(response.statusCode());|code-block|syntax|javascript|5180097|这里有更多信息：https://openjdk.java.net/groups/net/httpclient/recipes.html#post|offset|length|5180098|entityMap|0|LINK|mutability|MUTABLE|url|https://openjdk.java.net/groups/net/httpclient/recipes.html#post^0|0|0|8|1S|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

Easy with java.net:
<pre><code>public void post(String uri, String data) throws Exception {
HttpClient client = HttpClient.newBuilder().build();
HttpRequest request = HttpRequest.newBuilder()
 .uri(URI.create(uri))
 .POST(BodyPublishers.ofString(data))
 .build();

HttpResponse&lt;?&gt; response = client.send(request, BodyHandlers.discarding());
System.out.println(response.statusCode());
</code></pre>
Here is more information:
<a href="https://openjdk.java.net/groups/net/httpclient/recipes.html#post" rel="nofollow noreferrer">https://openjdk.java.net/groups/net/httpclient/recipes.html#post</a>

lets assume this URL...

<pre><code>http://www.example.com/page.php?id=10 
</code></pre>

(Here id needs to be sent in a POST request)

I want to send the <code>id = 10</code> to the server's <code>page.php</code>, which accepts it in a POST method.

How can i do this from within Java?

I tried this :

<pre><code>URL aaa = new URL("http://www.example.com/page.php");
URLConnection ccc = aaa.openConnection();
</code></pre>

But I still can't figure out how to send it via POST

Sending HTTP POST Request In Java

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

让我们假设这个URL...http://www.example.com/page.php?id=10            (这里的id需要在POST请求中发送)我希望将id = 10发送到服务器的page.php，它在POST方法中接受它。我如何在Java中做到这一点？我试过这个：URL aaa = new URL(...

问使用Java发送HTTP POST请求
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问使用Java发送HTTP POST请求EN