How to send Request payload to REST API in java?

Question

I want to retrieve the JSON data from the following: https://git.eclipse.org/r/#/c/11376/

Request URL: https://git.eclipse.org/r/gerrit/rpc/ChangeDetailService

Request Method: POST

Request Headers:

Accept:application/json

Content-Type:application/json; charset=UTF-8

Request Payload:

{"jsonrpc":"2.0","method":"changeDetail","params":[{"id":11376}],"id":1}

I already tried this answer but I am getting 400 BAD REQUEST.

Can anyone help me sort this out?

Thanks.

Answer 1

The following code works for me.

//escape the double quotes in json string
String payload="{\"jsonrpc\":\"2.0\",\"method\":\"changeDetail\",\"params\":[{\"id\":11376}],\"id\":2}";
String requestUrl="https://git.eclipse.org/r/gerrit/rpc/ChangeDetailService";
sendPostRequest(requestUrl, payload);

method implementation:

public static String sendPostRequest(String requestUrl, String payload) {
    try {
        URL url = new URL(requestUrl);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();

        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Accept", "application/json");
        connection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
        OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream(), "UTF-8");
        writer.write(payload);
        writer.close();
        BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        StringBuffer jsonString = new StringBuffer();
        String line;
        while ((line = br.readLine()) != null) {
                jsonString.append(line);
        }
        br.close();
        connection.disconnect();
        return jsonString.toString();
    } catch (Exception e) {
            throw new RuntimeException(e.getMessage());
    }

}