如何使用java获取令牌

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class TokenFetcher {

    private static final String AUTHORIZATION_SERVER_URL = "https://your-auth-server/oauth/token";
    private static final String CLIENT_ID = "your-client-id";
    private static final String CLIENT_SECRET = "your-client-secret";
    private static final String GRANT_TYPE = "client_credentials";

    public static void main(String[] args) {
        try {
            String token = fetchToken();
            System.out.println("Access Token: " + token);
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        }
    }

    private static String fetchToken() throws IOException, InterruptedException {
        HttpClient client = HttpClient.newHttpClient();
        String auth = CLIENT_ID + ":" + CLIENT_SECRET;
        String encodedAuth = Base64.getEncoder().encodeToString(auth.getBytes(StandardCharsets.UTF_8));
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(AUTHORIZATION_SERVER_URL))
                .header("Content-Type", "application/x-www-form-urlencoded")
                .header("Authorization", "Basic " + encodedAuth)
                .POST(HttpRequest.BodyPublishers.ofString("grant_type=" + GRANT_TYPE))
                .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        if (response.statusCode() == 200) {
            String responseBody = response.body();
            // 解析JSON响应获取访问令牌
            // 这里假设响应体是JSON格式，例如：{"access_token":"your-access-token"}
            String accessToken = responseBody.split(":")[1].split("\"")[1];
            return accessToken;
        } else {
            throw new RuntimeException("Failed to fetch token: " + response.statusCode());
        }
    }
}