[Google API + Springboot] Gmail 록록 취득하기

1. Google API Client Library 종속성을 pom.xml 파일에 추가합니다.

<dependency>
    <groupId>com.google.apis</groupId>
    <artifactId>google-api-services-gmail</artifactId>
    <version>v1-rev20210115-1.30.9</version>
</dependency>

 

2. API 클라이언트 인증

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.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;

import java.io.IOException;
import java.security.GeneralSecurityException;
import java.util.Collections;

public class GmailService {

    private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
    private static final String APPLICATION_NAME = "Gmail API Java Quickstart";

    public static Gmail getGmailService() throws GeneralSecurityException, IOException {
        // Build the credentials
        GoogleCredentials credentials = GoogleCredentials.getApplicationDefault().createScoped(Collections.singleton(GmailScopes.GMAIL_LABELS));
        HttpCredentialsAdapter credentialsAdapter = new HttpCredentialsAdapter(credentials);

        // Build the Gmail API client
        final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
        Gmail service = new Gmail.Builder(HTTP_TRANSPORT, JSON_FACTORY, credentialsAdapter)
                .setApplicationName(APPLICATION_NAME)
                .build();

        return service;
    }
}

 

3. Gmail 주소 목록 가져오기.

import com.google.api.services.gmail.model.Label;
import com.google.api.services.gmail.model.ListLabelsResponse;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class GmailAddressService {

    public static List<String> getGmailAddresses(Gmail service) throws IOException {
        List<String> gmailAddresses = new ArrayList<>();
        String user = "me";

        ListLabelsResponse listResponse = service.users().labels().list(user).execute();
        List<Label> labels = listResponse.getLabels();

        for (Label label : labels) {
            if (label.getType().equals("user") && label.getName().contains("email")) {
                gmailAddresses.add(label.getName());
            }
        }

        return gmailAddresses;
   }
}