1.pom依赖

        <dependency>
	        <groupId>org.springframework.cloud</groupId>
	        <artifactId>spring-cloud-gcp-starter</artifactId>
            <version>1.2.6.RELEASE</version>
	    </dependency>
	    <dependency>
		    <groupId>org.springframework.cloud</groupId>
		    <artifactId>spring-cloud-gcp-starter-pubsub</artifactId>
		    <version>1.2.6.RELEASE</version>
		</dependency>
	    <!-- Firebase Admin SDK -->
	    <dependency>
	        <groupId>com.google.firebase</groupId>
	        <artifactId>firebase-admin</artifactId>
	        <version>8.1.0</version>
	    </dependency>
	    <!--pubsub-->
	    <dependency>
		    <groupId>com.google.guava</groupId>
		    <artifactId>guava</artifactId>
		    <version>30.1-jre</version>
		</dependency>
		<dependency>
		    <groupId>com.google.protobuf</groupId>
		    <artifactId>protobuf-java</artifactId>
		    <version>3.14.0</version>
		</dependency>

2.yml配置

spring:
  cloud:
    gcp:
      credentials:
        location: file:/data/reco-data/********.json
      project-id: *****
      pubsub:
        enabled: true
google:
  auth-file-path: /data/reco-data/*****.json
  project-num-id: *****
  androidApps: *****
  firebase: 
    topic: ***

3.代码

package com.****.service.impl;

import java.io.FileInputStream;
import java.util.Arrays;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.cloud.gcp.pubsub.core.publisher.PubSubPublisherTemplate;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.PubsubMessage;
import com.****.service.DataRelayService;
import com.google.auth.oauth2.AccessToken;
import com.google.auth.oauth2.GoogleCredentials;

import lombok.extern.slf4j.Slf4j;

@Service
@Slf4j
public class DataRelayServiceImp implements DataRelayService {

	private final RestTemplate restTemplate;

    public DataRelayServiceImp(RestTemplateBuilder restTemplateBuilder) {
        this.restTemplate = restTemplateBuilder.build();
    }

    @Autowired
    private PubSubPublisherTemplate pubSubTemplate;

    @Value("${google.project-num-id}")
    private String projectNumId;
    @Value("${google.firebase.topic}")
    private String firebaseTopic;
    @Value("${google.auth-file-path}")
    private String filePath;

    @Value("#{'${google.androidApps}'.split(',')}")
    private List<String> androidApps;
	@Override
	public void getApiData() {
		// 加载服务账号密钥
		try {
			List<String> scopes = Arrays.asList("https://www.googleapis.com/auth/firebase.readonly",
					"https://www.googleapis.com/auth/cloud-platform");
			GoogleCredentials credentials = GoogleCredentials.fromStream(new FileInputStream(filePath)).createScoped(scopes);

			// 强制刷新以获取新的访问令牌
			credentials.refresh();
			AccessToken token = credentials.getAccessToken();

			// 获取令牌值
			String accessToken = token.getTokenValue();
			log.info("token----" + token);
			for (String androidApp : androidApps) {
				String url = new StringBuilder("https://fcmdata.googleapis.com/v1beta1/projects/")
						.append(projectNumId)
						.append("/androidApps/")
						.append(androidApp)
						.append("/deliveryData")
						.toString();
				HttpHeaders headers = new HttpHeaders();
				headers.add("Authorization", "Bearer " + accessToken);

				// 创建 HttpEntity
				HttpEntity<String> entity = new HttpEntity<>("parameters", headers);

				// 发送 GET 请求
				ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
				log.info("==============" + response.getBody());
				ByteString data = ByteString.copyFromUtf8(response.getBody());
				PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();
				String res = pubSubTemplate.publish(firebaseTopic, pubsubMessage).get();
				log.info("pubsub 发布结果 = {}", res);
			}
		} catch (Exception e) {
			log.error("firebase异常=========" + e);
		}

	}
}