谷歌无法获取访问；令牌

我正在开发一个访问谷歌获取权限之后操作谷歌邮箱API的功能，现在在访问谷歌获取访问令牌出现问题
以下是我的开发代码：

import com.google.api.client.googleapis.auth.oauth2.GoogleCredential;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.admin.directory.Directory;
import com.google.api.services.admin.directory.DirectoryScopes;

import java.io.*;
import java.net.URISyntaxException;
import java.security.*;
import java.util.Arrays;
import java.util.Collections;

public class GoogleApiAuthUtil {

    /** Email of the Service Account */
    private static final String SERVICE_ACCOUNT_EMAIL = "xxxxx@testproject-355611.iam.gserviceaccount.com";

    /** Path to the Service Account's Private Key file */
    private static final String SERVICE_ACCOUNT_PKCS12_FILE_PATH = "p12key.p12";

    /**
     * Build and returns a Directory service object authorized with the service accounts
     * that act on behalf of the given user.
     *
     * @param userEmail The email of the user. Needs permissions to access the Admin APIs.
     * @return Directory service object that is ready to make requests.
     */
    public static Directory getDirectoryService(String userEmail) throws GeneralSecurityException,
            IOException, URISyntaxException {
        FileInputStream inputStream = new FileInputStream(file);
        HttpTransport httpTransport = new NetHttpTransport();
        GsonFactory jsonFactory = new GsonFactory();
        GsonFactory defaultInstance = GsonFactory.getDefaultInstance();
        GoogleCredential credential = new GoogleCredential.Builder()
                .setTransport(httpTransport)
                .setJsonFactory(jsonFactory)
                .setServiceAccountId(SERVICE_ACCOUNT_EMAIL)
                .setServiceAccountScopes(Collections.singleton(DirectoryScopes.ADMIN_DIRECTORY_USER))
                .setServiceAccountUser(userEmail)
                .setServiceAccountPrivateKeyFromP12File(new java.io.File(SERVICE_ACCOUNT_PKCS12_FILE_PATH))
                .build();
       
        Directory directory = new Directory.Builder(httpTransport, jsonFactory, null)
                .setHttpRequestInitializer(credential).build();
        return directory;
    }
}

以下是运行结果：

 [2022-07-28 16:38:12.616 employee-account ERROR ,, http-nio-8090-exec-2 com.employeeaccount.common.tool.exceptio n.GlobalExceptionHandler    java.lang.IllegalArgumentException
     com.google.common.base.Preconditions.checkArgument(Preconditions.java:131)
     com.google.api.client.util.Preconditions.checkArgument(Preconditions.java:35)
     com.google.api.client.googleapis.auth.oauth2.GoogleCredential.(GoogleCredential.java:317)
     com.google.api.client.googleapis.auth.oauth2.GoogleCredential$Builder.build(GoogleCredential.java:516)
     com.shareit.employeeaccount.common.utils.email.GoogleApiAuthUtil.getDirectoryService(GoogleApiAuthUtil.java:74)
     com.shareit.employeeaccount.controller.email.EmailController.test(EmailController.java:197)

我尝试了很多方法，通过查询得知应该是 GoogleCredential.build 的时候参数构建问题，但是还是无法解决，希望来个能人指点一下迷津。

直接将对象new出来，然后再set参数
GoogleCredential credential = new GoogleCredential();
credential .setTransport(httpTransport);