Youtube API 中的 NullPointerExceptions

Question

我目前正在尝试学习如何使用 Youtube API 和其他东西，但我遇到了一些 NullPointerException 错误，我就是不知道为什么...

我已经尝试了在文档中可以找到的所有内容，但没有任何改变。

private static final String APPLICATION_NAME = "API code samples";
private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();

/**
 * Create an authorized Credential object.
 *
 * @return an authorized Credential object.
 * @throws IOException
 */
public static Credential authorize(final NetHttpTransport httpTransport) throws IOException {
    // Load client secrets.
    InputStream in = CreateBroadcast.class.getResourceAsStream(CLIENT_SECRETS);
    GoogleClientSecrets clientSecrets =
      GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));
    // Build flow and trigger user authorization request.
    GoogleAuthorizationCodeFlow flow =
        new GoogleAuthorizationCodeFlow.Builder(httpTransport, JSON_FACTORY, clientSecrets, SCOPES)
        .build();
    Credential credential =
        new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");
    return credential;
}

/**
 * Build and return an authorized API client service.
 *
 * @return an authorized API client service
 * @throws GeneralSecurityException, IOException
 */
public static YouTube getService() throws GeneralSecurityException, IOException {
    final NetHttpTransport httpTransport = GoogleNetHttpTransport.newTrustedTransport();
    Credential credential = authorize(httpTransport);
    return new YouTube.Builder(httpTransport, JSON_FACTORY, credential)
        .setApplicationName(APPLICATION_NAME)
        .build();
}

/**
 * Call function to create API service object. Define and
 * execute API request. Print API response.
 *
 * @throws GeneralSecurityException, IOException, GoogleJsonResponseException
 */
public static void main(String[] args)
    throws GeneralSecurityException, IOException, GoogleJsonResponseException {
    YouTube youtubeService = getService();
    
    // Define the LiveBroadcast object, which will be uploaded as the request body.
    LiveBroadcast liveBroadcast = new LiveBroadcast();
    
    // Add the contentDetails object property to the LiveBroadcast object.
    LiveBroadcastContentDetails contentDetails = new LiveBroadcastContentDetails();
    contentDetails.setEnableClosedCaptions(true);
    contentDetails.setEnableContentEncryption(true);
    contentDetails.setEnableDvr(true);
    contentDetails.setEnableEmbed(true);
    contentDetails.setRecordFromStart(true);
    contentDetails.setStartWithSlate(true);
    liveBroadcast.setContentDetails(contentDetails);
    
    // Add the snippet object property to the LiveBroadcast object.
    LiveBroadcastSnippet snippet = new LiveBroadcastSnippet();
    snippet.setScheduledStartTime(new DateTime("2024-01-30T00:00:00.000Z"));
    snippet.setTitle("Test broadcast");
    liveBroadcast.setSnippet(snippet);
    
    // Add the status object property to the LiveBroadcast object.
    LiveBroadcastStatus status = new LiveBroadcastStatus();
    status.setPrivacyStatus("unlisted");
    liveBroadcast.setStatus(status);

    // Define and execute the API request
    YouTube.LiveBroadcasts.Insert request = youtubeService.liveBroadcasts()
        .insert("snippet,contentDetails,status", liveBroadcast);
    LiveBroadcast response = request.execute();
    System.out.println(response);
}

这些是我不断收到的错误：

Exception in thread "main" java.lang.NullPointerException
at java.base/java.io.Reader.<init>(Reader.java:167)
at java.base/java.io.InputStreamReader.<init>(InputStreamReader.java:72)
at com.google.api.services.samples.youtube.cmdline.live.CreateBroadcast.authorize(CreateBroadcast.java:47)
at com.google.api.services.samples.youtube.cmdline.live.CreateBroadcast.getService(CreateBroadcast.java:65)
at com.google.api.services.samples.youtube.cmdline.live.CreateBroadcast.main(CreateBroadcast.java:79)

如果这是一个愚蠢的问题，我很抱歉 :) 在此先感谢蒂洛

Answer 1

这与 YouTube API 无关。

CreateBroadcast.class.getResourceAsStream(CLIENT_SECRETS) 返回 null，as the documentation states it will，因为 CLIENT_SECRETS 不包含指向现有资源的资源 URL。

请注意，它必须是相对 URL，而不是文件路径。在所有平台上，相对 URL 表示带有正斜杠 (/) 的路径。

如果您从 .jar 文件运行，您可以简单地验证 .jar 文件是否包含您请求的资源：

• 如果 CLIENT_SECRETS 以初始斜杠开头，则它相对于 .jar 文件的根目录。这意味着，如果 CLIENT_SECRETS 是 "/config/secrets.txt"，您的 .jar 文件需要包含 config/secrets.txt 条目。
• 如果 CLIENT_SECRETS 不以斜杠开头，则它与 CreateBroadcast 类的包相关。这意味着，如果 CLIENT_SECRETS 为 "secrets.txt"，则 .jar 文件需要包含 com/google/api/services/samples/youtube/cmdline/live/secrets.txt 条目。

如果您不是从 .jar 文件运行，则适用相同的规则，但您需要检查 IDE 添加的运行时类路径中的每个目录。许多 IDE 将遵循 Maven 约定，并且只会使用项目中的 target/classes 子目录。

在所有情况下，如果 CLIENT_SECRETS 的值不是现有资源的路径，则 getResourceAsStream 方法返回 null。然后，您将该 null 传递给 new InputStreamReader，这就是您的异常的原因。

Answer 2

很可能找不到CLIENT_SECRETS 资源，CreateBroadcast.class.getResourceAsStream(CLIENT_SECRETS) 返回null。在下一行中使用null 调用new InputStreamReader(in) 以NPE 结尾。