Spring Boot调用GitHub API携带Bearer Token遇401未授权问题

我正在开发一款可自动邀请组织成员的Spring Boot应用，测试调用GitHub API时，明明携带了Bearer Token，却持续收到401 Unauthorized错误。

代码示例 #

public class RestClient {

    private static final String GET_INVITATION = "https://api.github.com/orgs/ORG-Example/invitations";
    private static final String token = "THE TOKEN";

    static RestTemplate restTemplate = new RestTemplate();

    public static void main(String[] args) {
        callListOrganizationAPI();
    }

    public static void callListOrganizationAPI(){

        HttpHeaders headers = new HttpHeaders();
        headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
        headers.set("Authorization","Bearer"+ token);

        HttpEntity<String> request = new HttpEntity<String>(headers);
        ResponseEntity<String> result =  restTemplate.exchange(GET_INVITATION, HttpMethod.GET,request,String.class);

        String json = result.getBody();
        System.out.println(json);
    }

}

报错信息 #

22:14:36.171 [main] DEBUG org.springframework.web.client.RestTemplate - HTTP GET https://api.github.com/orgs/ORG-Example/invitations
22:14:36.179 [main] DEBUG org.springframework.web.client.RestTemplate - Accept=[text/plain, application/json, application/*+json, */*]
22:14:36.598 [main] DEBUG org.springframework.web.client.RestTemplate - Response 401 UNAUTHORIZED
Exception in thread "main" org.springframework.web.client.HttpClientErrorException$Unauthorized: 401 Unauthorized: "{"message":"Requires authentication","documentation_url":"https://docs.github.com/rest/reference/orgs#list-pending-organization-invitations"}"
    at org.springframework.web.client.HttpClientErrorException.create(HttpClientErrorException.java:105)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:168)
    at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:122)
    at org.springframework.web.client.ResponseErrorHandler.handleError(ResponseErrorHandler.java:63)
    at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:819)
    at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:777)
    at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711)
    at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:602)
    at com.texhnolyze.githubapi.RestClient.callListOrganizationAPI(RestClient.java:26)
    at com.texhnolyze.githubapi.RestClient.main(RestClient.java:16)

内容的提问来源于stack exchange，提问作者Artyom47