谷歌驱动器API无法列出文件(v3 Java）

Question

    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");

}

    }

    }    

更详细地说。我正在用一种有点非常规的方法来尝试。我只使用命令行来运行（没有IDE，没有gradle）。

这里有一个链接到一个ss与我的输出在命令提示符。cmd输出

假设我实际上是在访问Google Drive中的元数据，并且Drive.files嵌套在抽象映射（java.util.AbstractMap）中，我应该能够返回映射的大小，从而通过返回多少文件来了解它在哪里搜索。

我不确定是怎么回事。第一次编译和运行时，我在chrome中打开了一个选项卡，要求获得访问要驱动的元数据的权限。第二次，它会给出“警告：无法更改每个人的权限：”错误。除此之外，var1('set to service.files()')在使用toString()时返回com.google.api.services.drive.drive$files@458ad742。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，但显然它没有这样做。

我可能误解了很多东西，所以请原谅我。谢谢你的帮助。

StoredCredential

因此，仅从这一点来说，我（认为）连接到谷歌驱动器。但是，默认的代码应该列出10个文件的名称和ID，它什么都不能做。

如何运行程序：下面是我用来编译和运行CMD代码的批处理文件。

    jar cfe DriveQuickstart.jar Quickstart DriveQuickstart.class
    javac -cp ./* DriveQuickstart.java
    java -cp ./* DriveQuickstart

出于某种原因，我不知道/理解，这是不从导入的不存在的jar文件返回方法的唯一方法。

Answer 1

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