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使用 Java 将事件发布到命名空间主题
本文提供了使用 Java 发布 CloudEvent 的快速分步指南。 本文中的示例代码在发送事件时使用 CloudEvents JSON 格式。
先决条件
在继续操作之前,需要满足的先决条件如下:
命名空间、主题和事件订阅。
最新的 beta 版 SDK 包。 如果使用 maven,则可以查阅 maven 中央存储库。
重要
Beta 版本包中提供了拉取传递数据平面 SDK 支持。 应在项目中使用最新的 beta 版本包。
支持 Java 的 IDE(如 IntelliJ IDEA、Eclipse IDE 或 Visual Studio Code)。
运行 Java 8 语言级别的 Java JRE。
将事件发布到命名空间主题
使用以下类了解发布事件的基本步骤。
package com.azure.messaging.eventgrid.samples;
import com.azure.core.credential.AzureKeyCredential;
import com.azure.core.http.HttpClient;
import com.azure.core.models.CloudEvent;
import com.azure.core.models.CloudEventDataFormat;
import com.azure.core.util.BinaryData;
import com.azure.messaging.eventgrid.EventGridClient;
import com.azure.messaging.eventgrid.EventGridClientBuilder;
import com.azure.messaging.eventgrid.EventGridMessagingServiceVersion;
import java.time.OffsetDateTime;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
/**
* <p>Simple demo publisher of CloudEvents to Event Grid namespace topics.
*
* This code samples should use Java 1.8 level or above to avoid compilation errors.
*
* You should consult the resources below to use the client SDK and set up your project using maven.
* @see <a href="https://github.com/Azure/azure-sdk-for-java/tree/main/sdk/eventgrid/azure-messaging-eventgrid">Event Grid data plane client SDK documentation</a>
* @see <a href="https://github.com/Azure/azure-sdk-for-java/blob/main/sdk/boms/azure-sdk-bom/README.md">Azure BOM for client libraries</a>
* @see <a href="https://aka.ms/spring/versions">Spring Version Mapping</a> if you are using Spring.
* @see <a href="https://aka.ms/azsdk">Tool with links to control plane and data plane SDKs across all languages supported</a>.
*</p>
*/
public class NamespaceTopicPublisher {
private static final String TOPIC_NAME = "<yourNamespaceTopicName>";
public static final String ENDPOINT = "<yourFullHttpsUrlToTheNamespaceEndpoint>";
public static final int NUMBER_OF_EVENTS_TO_BUILD_THAT_DOES_NOT_EXCEED_100 = 10;
//TODO Do NOT include keys in source code. This code's objective is to give you a succinct sample about using Event Grid, not to provide an authoritative example for handling secrets in applications.
/**
* For security concerns, you should not have keys or any other secret in any part of the application code.
* You should use services like Azure Key Vault for managing your keys.
*/
public static final AzureKeyCredential CREDENTIAL = new AzureKeyCredential("<namespace key>");
public static void main(String[] args) {
//TODO Update Event Grid version number to your desired version. You can find more information on data plane APIs here:
//https://learn.microsoft.com/en-us/rest/api/eventgrid/.
EventGridClient eventGridClient = new EventGridClientBuilder()
.httpClient(HttpClient.createDefault()) // Requires Java 1.8 level
.endpoint(ENDPOINT)
.serviceVersion(EventGridMessagingServiceVersion.V2023_06_01_PREVIEW)
.credential(CREDENTIAL).buildClient(); // you may want to use .buildAsyncClient() for an asynchronous (project reactor) client.
List<CloudEvent> cloudEvents = buildCloudEvents(NUMBER_OF_EVENTS_TO_BUILD_THAT_DOES_NOT_EXCEED_100);
eventGridClient.publishCloudEvents(TOPIC_NAME, cloudEvents);
System.out.println("--> Number of events published: " + NUMBER_OF_EVENTS_TO_BUILD_THAT_DOES_NOT_EXCEED_100); // There is no partial publish. Either all succeed or none.
}
/**
* <p>Builds a list of valid CloudEvents for testing purposes</p>
* @param numberOfEventsToBuild this should not exceed 100, which is the maximum number of events allowed in a single HTTP request or 1MB in size, whichever is met first.
* @return the list of CloudEvents
*/
private static List<CloudEvent> buildCloudEvents(int numberOfEventsToBuild) {
List<CloudEvent> cloudEvents = new ArrayList<>(numberOfEventsToBuild);
while (numberOfEventsToBuild >= 1) {
cloudEvents.add(buildCloudEvent());
numberOfEventsToBuild--;
}
return cloudEvents;
}
/**
* <p>Builds a valid CloudEvent for testing purposes.</p>
* @return a CloudEvent
*/
private static CloudEvent buildCloudEvent() {
String orderId = Integer.toString(new Random().nextInt(1000-10+1) + 10); // Generates a random integer between 1000 and 1 (exclusive)
return new CloudEvent("/account/a-4305/orders", "com.MyCompanyName.OrderCreated",
BinaryData.fromObject(new HashMap<String, String>() {
{
put("orderId", orderId);
put("orderResourceURL", "https://www.MyCompanyName.com/orders/" + orderId);
put("isRushOrder", "true");
put("customerType", "Institutional");
}
}), CloudEventDataFormat.JSON, "application/json")
.setTime(OffsetDateTime.now());
}
}
后续步骤
- 请参阅 Java API 参考。
- 如果要连接到事件网格并控制读取事件的时间和速率,请参阅使用拉取传递接收事件。 还可以使用专用终结点通过拉取传递从事件网格读取事件。
- 如果需要使用事件中心作为目标订阅事件,请参阅使用推送传递订阅到事件中心的事件。
- 若要详细了解拉取传递模型,请参阅拉取传递概述。