问题

我想使用`HttpURLConnection`在Groovy中发送POST请求，但我无法使其工作。

```java-lang
HttpURLConnection conn = new URL("https://url").openConnection()
conn.setDoOutput(true)
conn.setRequestMethod("POST")
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded")
conn.getOutputStream().write("client_id=client_id&username=username&password=password&scope=api&grant_type=password".getBytes("UTF-8"))
assert conn.getResponseCode() == 403

我尝试过其他方法：Postman、Java OkHttp、Python请求和Java Unirest，它们都立即起作用。
这是Java Unirest的工作代码（感谢Postman）：

import kong.unirest.HttpResponse

HttpResponse<String> response = Unirest.post("https://url")
        .header("Content-Type", "application/x-www-form-urlencoded")
        .field("client_id", "client_id")
        .field("username", "username")
        .field("password", "password")
        .field("scope", "api")
        .field("grant_type", "password")
        .asString();

我知道这不是一个特定的Groovy问题，但也许有人知道为什么我的HttpURLConnection版本不起作用？

<details>
<summary>英文:</summary>

I want to send a post request in Groovy using `HttpURLConnection` and I can&#39;t get it to work.

```java-lang
HttpURLConnection conn = new URL(&quot;https://url&quot;).openConnection()
conn.setDoOutput(true)
conn.setRequestMethod(&quot;POST&quot;)
conn.setRequestProperty(&quot;Content-Type&quot;, &quot;application/x-www-form-urlencoded&quot;)
conn.getOutputStream().write(&quot;client_id=client_id&amp;username=username&amp;password=password&amp;scope=api&amp;grant_type=password&quot;.getBytes(&quot;UTF-8&quot;))
assert conn.getResponseCode() == 403

I have tried other ways: Postman, Java OkHttp, Python requests and Java Unirest and they all worked instantly.
Here is the working code for Java Unirest (credits to Postman):

import kong.unirest.HttpResponse

HttpResponse<String> response = Unirest.post("https://url")
        .header("Content-Type", "application/x-www-form-urlencoded")
        .field("client_id", "client_id")
        .field("username", "username")
        .field("password", "password")
        .field("scope", "api")
        .field("grant_type", "password")
        .asString();

I know this is not a particular Groovy question, but maybe somebody knows why my HttpURLConnection version doesn't work?

答案1

得分: 1

Here is the code translated into Chinese:

import java.nio.charset.StandardCharsets;
import java.net.HttpURLConnection;
import java.net.URL;
import java.io.DataOutputStream;

HttpURLConnection conn = new URL("https://url").openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
new DataOutputStream(conn.getOutputStream()).withCloseable {
    it.write("client_id=client_id&username=username&password=password&scope=api&grant_type=password".getBytes(StandardCharsets.UTF_8));
}

assert conn.getResponseCode() == 200;

请注意，我已经将代码翻译成了中文，您可以使用这个中文版本的代码。

import java.nio.charset.StandardCharsets

HttpURLConnection conn = new URL('https://url' ).openConnection()
conn.setDoOutput( true )
conn.setRequestMethod( "POST" )
conn.setRequestProperty( "Content-Type", "application/x-www-form-urlencoded")
new DataOutputStream(conn.getOutputStream()).withCloseable {
    it.write( "client_id=client_id&username=username&password=password&scope=api&grant_type=password".getBytes( StandardCharsets.UTF_8 ) )
}

assert conn.getResponseCode() == 200

答案2

得分: 1

添加 conn.setRequestProperty("Accept", "*/*") 或 conn.setRequestProperty("Accept", "application/json") 解决了我的问题。这有点奇怪，因为它在 Postman 中运行正常，而我明确没有将其放在标头中，但谁知道在幕后发生了什么。

我还相信这是与我连接的服务器相关的。似乎它不允许空的 Accept 标头，并在这种情况下返回代码 403，这真的没有什么帮助。