Java 11 HttpClient-缺少表单参数：grant_type

如何解决Java 11 HttpClient-缺少表单参数：grant_type

我正在尝试通过Java 11的HttpClient从Keycloack服务器获取访问令牌，但是我一直收到错误消息：

{
    "error":"invalid_request","error_description":"Missing form parameter: grant_type"
}

通过邮递员，我可以得到令牌。我在代码中所做的是：

        Map<String,String> values = new HashMap<>() {{
            put("username",username);
            put ("password",password);
            put("grant_type","password");
        }};

        ObjectMapper objectMapper = new ObjectMapper();
        String requestBody = objectMapper.writerWithDefaultPrettyPrinter()
                .writeValueAsString(values);

        HttpRequest request=HttpRequest.newBuilder()
                .uri(URI.create(tokenEndpoint))
                .setHeader("client_id",clientId)
                .setHeader("client_secret",clientSecret)
                .setHeader("content-type","application/x-www-form-urlencoded")
                .POST(HttpRequest.BodyPublishers.ofString(requestBody))
                .build();



        HttpClient.newHttpClient()
                .sendAsync(request,HttpResponse.BodyHandlers.ofString())
                .thenApply(HttpResponse::body)
                .thenAccept(System.out::println);

        /*
        //Tried also
        HttpResponse<String> response = client.send(request,HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
        */

我做错了什么或想念什么？

Keycloak Missing form parameter: grant_type无效。

解决方法

这是我们完成登录的方式：

MultiValueMap<String,String> requestParams = new LinkedMultiValueMap<>();
requestParams.add("client_id",keycloakProperties.getResource());
requestParams.add("username",username);
requestParams.add("password",password);
requestParams.add("grant_type","password");
requestParams.add("client_secret",String.valueOf(keycloakProperties.getCredentials().get("secret")));
requestParams.add("scope","openid");

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

HttpEntity<MultiValueMap<String,String>> request = new HttpEntity<>(requestParams,headers);

String url = keycloakProperties.getAuthServerUrl() + "/realms/" + keycloakProperties.getRealm() + "/protocol/openid-connect/token";

AccessTokenResponse keycloakAccessToken = getAccessTokenResponse(request,url);


// sometimes SSL handshake was failing,so catching error and trying again :)
private AccessTokenResponse getAccessTokenResponse(HttpEntity<MultiValueMap<String,String>> request,String url) {
    try {
        ResponseEntity<AccessTokenResponse> response = restTemplate.postForEntity(url,request,AccessTokenResponse.class);
        return response.getBody();
    } catch (ResourceAccessException e) {
        log.error("KeyCloak getAccessTokenResponse: " + e.getMessage());
        try {
            ResponseEntity<AccessTokenResponse> response = restTemplate.postForEntity(url,AccessTokenResponse.class);
            return response.getBody();
        } catch (Exception ex) {
            throw ex;
        }
    } catch (Exception e) {
        throw e;
    }
}

,

在.setHeader("content-type","application/x-www-form-urlencoded")行中，该请求需要表单数据， 但是您正在通过ObjectMapper.writeValueAsString()在请求正文中发送json。

如果您尝试发送表单数据，则应该是正确的编码：

String requestBody = "username=" + username + "password=" + password + "grant_type=password"

如果API需要JSON，则将内容类型标头更改为application/json：

HttpRequest request=HttpRequest.newBuilder()
    ...
    .setHeader("content-type","application/json")
    ...