Google驱动器API无法列出文件（v3 Java）

我在Java中使用GoogleAPI，并有以下代码片段

    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.io.FileInputStream;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.security.GeneralSecurityException;
    import java.util.Collections;
    import java.util.List;
    import java.lang.Object;
    import java.util.ArrayList;

    import com.google.api.client.auth.oauth2.Credential;
    import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
    import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
    import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
    import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
    import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
    import com.google.api.client.http.javanet.NetHttpTransport;
    import com.google.api.client.json.JsonFactory;
    import com.google.api.client.json.jackson2.JacksonFactory;
    import com.google.api.client.util.store.FileDataStoreFactory;
    import com.google.api.services.drive.Drive;
    import com.google.api.services.drive.Drive.Files;
    import com.google.api.services.drive.DriveScopes;
    import com.google.api.services.drive.model.File;
    import com.google.api.services.drive.model.FileList;


    public class DriveQuickstart {

        private static final String APPLICATION_NAME = "DriveQuickstart";
        private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
        private static final String TOKENS_DIRECTORY_PATH = "tokens";

        // * Global instance of the scopes required by this quickstart.
        // * If modifying these scopes, delete your previously saved tokens/ folder.

        private static final List<String> SCOPES = Collections.singletonList(DriveScopes.DRIVE_METADATA_READONLY);
        private static final String CREDENTIALS_FILE_PATH = "C:/Quickstart/src/main/resources/client_secret.json";

// * Creates an authorized Credential object.
// * @param HTTP_TRANSPORT The network HTTP Transport.
// * @return An authorized Credential object.
// * @throws IOException If the client_secret.json file cannot be found.
// */
private static Credential getCredentials(final NetHttpTransport HTTP_TRANSPORT) throws IOException {
    // Load client secrets.
    InputStream in = new FileInputStream(CREDENTIALS_FILE_PATH);
    if (in == null) {
        throw new FileNotFoundException("Resource not found: " + CREDENTIALS_FILE_PATH);
    }
    GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));

    // Build flow and trigger user authorization request.
    GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
            HTTP_TRANSPORT, JSON_FACTORY, clientSecrets, SCOPES)
            .setDataStoreFactory(new FileDataStoreFactory(new java.io.File(TOKENS_DIRECTORY_PATH)))
            .setAccessType("offline")
            .build();
    LocalServerReceiver receiver = new LocalServerReceiver.Builder().setPort(8888).build();
    return new AuthorizationCodeInstalledApp(flow, receiver).authorize("user");

}

public static void main(String[] args) throws IOException, GeneralSecurityException {
    try
    {
    // Build a new authorized API client service.
    System.out.println("This is a test line");

    //declare final variable NetHttpTransport and GoogleNetHttpTransport from import statements
    final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
    System.out.println("This is the second test line");
    Drive service = new Drive.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
            .setApplicationName(APPLICATION_NAME)
            .build();

    System.out.println("This is the third test line");

    // Print the names and IDs for files.
    FileList result = service.files().list()
            .setPageSize(10)
            .setFields("nextPageToken, files(id, name)")
            .execute();
    List<File> files = result.getFiles();
    if (files == null || files.isEmpty()) {
        System.out.println("No files found.");
    } else {
        System.out.println("Files:");
        for (File file : files) {
            System.out.printf("%s (%s)\n", file.getName(), file.getId());
        }
    }
    Drive.Files var1 = service.files();
    System.out.println("var1 = " + var1.toString());
    Drive.Files.List var2 = var1.list();
    if (var2 == null)
        System.out.println("null");
    else {
        System.out.printf("Var2 size is: %d\n", var2.size() );
    }
    //iterate through map and print results
    }
    catch(Exception  e){
        System.out.println("error");
    }

    System.out.println("This is the fourth test line");

}

    }

    }    

---

出于某种原因，我不知道/不理解，这是唯一一种不会从不存在的导入jar文件返回方法的方法。

请熟悉，看看如何获得API调用的结果

问题 1-自动设置许可证 我不知道发生了什么事。第一次编译和运行时，我在chrome中打开了一个选项卡，请求获得访问元数据的权限以驱动程序。第二次，它给出了“警告：无法更改每个人的权限：”错误

这似乎与我有关。这可能意味着用于从中运行代码的文件夹具有与预期不同的权限

如果您将代码放在桌面上（例如），然后从桌面上运行，是否会发生这种情况

2-

toString（）

最重要的是，var1（'set to service.files（）'）返回com.google.api.services.drive.drive$Files@458ad742使用toString（）时。分配给var2的子类service.files（）.list（）应该返回我的Google驱动器中的文件列表，但显然不是这样

这个奇怪的字符串是Java打印类实例的方式

com.google.api.services.drive.Drive$Files@458ad742
<NAMESPACE>$<CLASS>@<HASHCODE>

com.google.api.services.drive.drive$Files@458ad742
$@

toString

方法打印出这个事实意味着这个方法没有为此被覆盖，因此它调用了常规

---

要打印出您想要看到的内容，请尝试嵌套方法。

我已经按照教程进行了操作，我打开了chrome中的选项卡，请求访问元数据的权限。之后我的问题是打印10个文件的名称和ID的代码没有运行。因此，我试图通过返回值来手动检查它是否正在访问Drive.Files及其子类。Hello@Phanotak，在授予应用程序权限后，您看到了什么？如果可能，请添加完整的日志输出和屏幕截图。发布完整的代码，并添加了我的命令提示符输出的屏幕截图和它打开的google选项卡。如果我删除StoredCredential并运行它，它会打开google选项卡，发出不安全通知，选择帐户并请求访问google drive上元数据的权限。我不知道它是否与此链接有关。让它工作起来。我所做的只是重做教程并将其直接放入C://Quickstart，而不是将一些复杂的长目录名放入4-5个子文件夹中。谢谢你的帮助，我真的很感激有人愿意帮忙。

com.google.api.services.drive.Drive$Files@458ad742
<NAMESPACE>$<CLASS>@<HASHCODE>