HTTP post / API请求在bash上从CURL发送时起作用，从Apache http失败

Question

I'm trying to use apache http components to interface with the Spotify api. The request I'm trying to send is detailed here under #1. When I send this request from bash using curl

curl -H "Authorization: Basic SOMETOKEN" -d grant_type=client_credentials https://accounts.spotify.com/api/token

I get back a token like the website describes

However the following java code, which as far as I can tell executes the same request, gives back a 400 error

Code

    String encoded = "SOMETOKEN";
    CloseableHttpResponse response = null;
    try {
        CloseableHttpClient client = HttpClients.createDefault();
        URI auth = new URIBuilder()
                .setScheme("https")
                .setHost("accounts.spotify.com")
                .setPath("/api/token")
                .setParameter("grant_type", "client_credentials")
                .build();

        HttpPost post = new HttpPost(auth);
        Header header = new BasicHeader("Authorization", "Basic " + encoded);
        post.setHeader(header);
        try {
            response = client.execute(post);
            response.getEntity().writeTo(System.out);
        }
        finally {
            response.close();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

Error

{"error":"server_error","error_description":"Unexpected status: 400"}

The URI that the code prints is looks like this

https://accounts.spotify.com/api/token?grant_type=client_credentials

And the header looks like this

Authorization: Basic SOMETOKEN

Am I not constructing the request correctly? Or am I missing something else?

Answer 1

Use form url-encoding for the data in the body with the content-type application/x-www-form-urlencoded :

CloseableHttpClient client = HttpClients.createDefault();

HttpPost post = new HttpPost("https://accounts.spotify.com/api/token");
post.setHeader(HttpHeaders.CONTENT_TYPE, "application/x-www-form-urlencoded");
post.setHeader(HttpHeaders.AUTHORIZATION, "Basic " + encoded);
StringEntity data = new StringEntity("grant_type=client_credentials");
post.setEntity(data);

HttpResponse response = client.execute(post);