Google Cloud Pub / Sub，Java客户端未发布消息

时间：2019-03-27 08:40:51

标签： java google-cloud-pubsub

我正在尝试使用Google Cloud Pub / Sub将消息发布到某个主题。我一直在关注这个tutorial。我已经成功使用以下方法创建了Topic。

    public static Topic createTopic(String topic) throws IOException {
    try (TopicAdminClient topicAdminClient = TopicAdminClient.create(topicAdminSettings)) {
      ProjectTopicName topicName = ProjectTopicName.of(projectId, topic);
      return topicAdminClient.createTopic(topicName);
    }
  }

以下方法从新创建的topic-id返回Topic。

    public static String getTopicId(String topicName) throws IOException {
    String topic_id = null;
    try (TopicAdminClient topicAdminClient = TopicAdminClient.create(topicAdminSettings)) {
      ListTopicsRequest listTopicsRequest =
          ListTopicsRequest.newBuilder().setProject(ProjectName.format(projectId)).build();
      ListTopicsPagedResponse response = topicAdminClient.listTopics(listTopicsRequest);
      Iterable<Topic> topics = response.iterateAll();
      for (Topic topic : topics) {
        // return the topic id for the given topic
         if (topic.getName().toLowerCase().contains(topicName.toLowerCase())) {
           topic_id = topic.getName();
         }
      }
    }
    return topic_id;
  }

但是当我尝试发布消息时，请使用以下方法

    public static void publishMessages(String topic) throws Exception {
    String topicId = getTopicId(topic);
    ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
    Publisher publisher = null;
    try {
      // Create a publisher instance with default settings bound to the topic
      publisher = Publisher.newBuilder(topicName).build();

      List<String> messages = Arrays.asList("first message", "second message");

      for (final String message : messages) {
        ByteString data = ByteString.copyFromUtf8(message);
        PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();

        // Once published, returns a server-assigned message id (unique within the topic)
        ApiFuture<String> future = publisher.publish(pubsubMessage);

        // Add an asynchronous callback to handle success / failure
        ApiFutures.addCallback(
            future,
            new ApiFutureCallback<String>() {

              @Override
              public void onFailure(Throwable throwable) {
                if (throwable instanceof ApiException) {
                  ApiException apiException = ((ApiException) throwable);
                  // details on the API exception
                  System.out.println(apiException.getStatusCode().getCode());
                  System.out.println(apiException.isRetryable());
                }
                System.out.println("Error publishing message : " + message);
              }

              @Override
              public void onSuccess(String messageId) {
                // Once published, returns server-assigned message ids (unique within the topic)
                System.out.println(messageId);
              }
            },
            MoreExecutors.directExecutor());
      }
    } finally {
      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
        publisher.awaitTermination(1, TimeUnit.MINUTES);
      }
    }

  }

我收到以下异常

Exception in thread "main" com.google.api.pathtemplate.ValidationException: Invalid character "/" in path section "projects/deft-idiom-234709/topics/test-topic".
at com.google.api.pathtemplate.PathTemplate.encodeUrl(PathTemplate.java:924)
at com.google.api.pathtemplate.PathTemplate.instantiate(PathTemplate.java:721)
at com.google.api.pathtemplate.PathTemplate.instantiate(PathTemplate.java:646)
at com.google.api.pathtemplate.PathTemplate.instantiate(PathTemplate.java:657)
at com.google.pubsub.v1.ProjectTopicName.toString(ProjectTopicName.java:119)
at com.google.cloud.pubsub.v1.Publisher.newBuilder(Publisher.java:460)
at pubsub.TopicAndPubSub.publishMessages(TopicAndPubSub.java:73)
at pubsub.TopicAndPubSub.main(TopicAndPubSub.java:121)

这是整个课程

import com.google.api.core.ApiFuture;
import com.google.api.core.ApiFutureCallback;
import com.google.api.core.ApiFutures;
import com.google.api.gax.core.FixedCredentialsProvider;
import com.google.api.gax.rpc.ApiException;
import com.google.auth.oauth2.ServiceAccountCredentials;
import com.google.cloud.pubsub.v1.Publisher;
import com.google.cloud.pubsub.v1.TopicAdminClient;
import com.google.cloud.pubsub.v1.TopicAdminClient.ListTopicsPagedResponse;
import com.google.cloud.pubsub.v1.TopicAdminSettings;
import com.google.common.util.concurrent.MoreExecutors;
import com.google.protobuf.ByteString;
import com.google.pubsub.v1.ListTopicsRequest;
import com.google.pubsub.v1.ProjectName;
import com.google.pubsub.v1.ProjectTopicName;
import com.google.pubsub.v1.PubsubMessage;
import com.google.pubsub.v1.Topic;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;

public class TopicAndPubSub {

  private static ServiceAccountCredentials creds;
  private static TopicAdminSettings topicAdminSettings;
  private static String projectId;

  static {
    try {
      creds = ServiceAccountCredentials.fromStream(new FileInputStream("C:/cred/Key.json"));
      topicAdminSettings = TopicAdminSettings.newBuilder()
          .setCredentialsProvider(FixedCredentialsProvider.create(creds)).build();
      projectId = creds.getProjectId();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  public static Topic createTopic(String topic) throws IOException {
    try (TopicAdminClient topicAdminClient = TopicAdminClient.create(topicAdminSettings)) {
      ProjectTopicName topicName = ProjectTopicName.of(projectId, topic);
      return topicAdminClient.createTopic(topicName);
    }
  }

  public static String getTopicId(String topicName) throws IOException {
    String topic_id = null;
    try (TopicAdminClient topicAdminClient = TopicAdminClient.create(topicAdminSettings)) {
      ListTopicsRequest listTopicsRequest =
          ListTopicsRequest.newBuilder().setProject(ProjectName.format(projectId)).build();
      ListTopicsPagedResponse response = topicAdminClient.listTopics(listTopicsRequest);
      Iterable<Topic> topics = response.iterateAll();
      for (Topic topic : topics) {
        // return the topic id for the given topic
         if (topic.getName().toLowerCase().contains(topicName.toLowerCase())) {
           topic_id = topic.getName();
         }
      }
    }
    return topic_id;
  }

  public static void publishMessages(String topic) throws Exception {
    String topicId = getTopicId(topic);
    ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
    Publisher publisher = null;
    try {
      // Create a publisher instance with default settings bound to the topic
      publisher = Publisher.newBuilder(topicName).build();

      List<String> messages = Arrays.asList("first message", "second message");

      for (final String message : messages) {
        ByteString data = ByteString.copyFromUtf8(message);
        PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();

        // Once published, returns a server-assigned message id (unique within the topic)
        ApiFuture<String> future = publisher.publish(pubsubMessage);

        // Add an asynchronous callback to handle success / failure
        ApiFutures.addCallback(
            future,
            new ApiFutureCallback<String>() {

              @Override
              public void onFailure(Throwable throwable) {
                if (throwable instanceof ApiException) {
                  ApiException apiException = ((ApiException) throwable);
                  // details on the API exception
                  System.out.println(apiException.getStatusCode().getCode());
                  System.out.println(apiException.isRetryable());
                }
                System.out.println("Error publishing message : " + message);
              }

              @Override
              public void onSuccess(String messageId) {
                // Once published, returns server-assigned message ids (unique within the topic)
                System.out.println(messageId);
              }
            },
            MoreExecutors.directExecutor());
      }
    } finally {
      if (publisher != null) {
        // When finished with the publisher, shutdown to free up resources.
        publisher.shutdown();
        publisher.awaitTermination(1, TimeUnit.MINUTES);
      }
    }

  }

  public static void main(String[] args) throws Exception {
    publishMessages("test-topic");
  }

}

我似乎无法解决它。有人可以帮忙吗？！

1 个答案:

答案 0 :(得分：1)

结果是，我需要使用Publisher构建setCredentialsProvider。必须在publishMessages方法中从

更改以下内容 
publisher = Publisher.newBuilder(topicName).build();

收件人

publisher = Publisher.newBuilder(
      topicName)
      .setCredentialsProvider(FixedCredentialsProvider.create(creds))
      .build();

现在按预期工作！

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