java - 在正文中使用 application/x-www-form-urlencoded 的 400 错误白色 Java Post

Question

        BufferedReader in = null;
        String response = "";
        String urlParameters = "";
try {
        URL obj = new URL("url");
         urlParameters = "grant_type=client_credentials";
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        con.setRequestMethod("POST");
        con.setRequestProperty("content-type", "application/x-www-form-urlencoded");
        con.setRequestProperty("authorization", "Basic value");

        con.setDoOutput(true);
        OutputStreamWriter wr = new OutputStreamWriter(con.getOutputStream());
        wr.write(urlParameters);

        // For POST only - START
        OutputStream os = con.getOutputStream();
        os.flush();
        os.close();
        // For POST only - END

        int responseCode = con.getResponseCode();
        System.out.println("\nSending 'GET' request to URL : " + os);
        System.out.println("Response Code================================================================================================================ : " + responseCode);

     in = new BufferedReader(
            new InputStreamReader(con.getInputStream()));
    String inputLine;



    while ((inputLine = in.readLine()) != null) {
        response = inputLine;
    }
    }
 finally {
        if (in != null) {
            in.close();

        }
    }   }

我正在使用此 API 来获取 TOKEN。但在所有情况下都得到 400。

根据文档API request details

请帮忙解决问题。

我认为这是添加正文部分的问题，因此我将正文部分附加到 URL 中，但也失败了。

对于此代码，我收到错误:sun.net.www.protocol.https.DelegateHttpsURLConnection

Answer 1

我更喜欢使用 Apache HTTP 客户端库而不是 HttpURLConnection。有关 HTTP 客户端的示例，请参阅 https://www.baeldung.com/httpclient-4-basic-authentication