# CloudEvents SDK 本章节介绍使用开源的CloudEvents Java SDK发布事件。 #### 前提条件 1. 获取并安装IntelliJ IDEA，如果未安装，请至[IntelliJ IDEA官方网站](https://www.jetbrains.com/idea/)下载。 2. 在**pom.xml** 中加入依赖。如何在Java环境中集成API请求签名的SDK请参考[AK/SK签名认证操作指导](https://support.huaweicloud.com/devg-apisign/api-sign-sdk-java.html)。 ``` io.cloudevents cloudevents-json-jackson ${cloudevents.version} com.huawei.apigateway java-sdk-core 3.1.2 ``` ![](https://support.huaweicloud.com/sdkreference-eg/public_sys-resources/note_3.0-zh-cn.png) "cloudevents.version"使用最新版本2.2.0。 #### 发布事件 发布事件的示例代码如下（以下加粗内容需要请根据实际情况替换）： ``` import com.alibaba.fastjson.JSONObject; import io.cloudevents.CloudEvent; import io.cloudevents.core.builder.CloudEventBuilder; import io.cloudevents.core.provider.EventFormatProvider; import io.cloudevents.jackson.JsonFormat; import lombok.extern.slf4j.Slf4j; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.conn.ssl.NoopHostnameVerifier; import org.apache.http.conn.ssl.SSLConnectionSocketFactory; import org.apache.http.conn.ssl.TrustSelfSignedStrategy; import org.apache.http.entity.StringEntity; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.ssl.SSLContexts; import org.apache.http.util.EntityUtils; import java.net.URI; import java.time.LocalDateTime; import java.time.OffsetDateTime; import java.time.format.DateTimeFormatter; import java.util.*; import java.util.stream.Collectors; @Slf4j public class PublishService { private static final String NAME = "l******"; private static final String PASSWORD = "******"; private static final String DOMAIN_NAME = "paa******01"; private static final String PROJECT_ID = "c5******f"; private static final String CHANNEL_ID = "ff******3"; private static final String ENDPOINT = "events.cn-north-4.myhuaweicloud.com"; private static final String URL = "https://" + ENDPOINT + "/v1/" + PROJECT_ID + "/channels/" + CHANNEL_ID + "/events"; private static final String SOURCE = "test_source"; private static final String IAM_ENDPOINT = "iam.cn-north-4.myhuaweicloud.com"; private static final String IAM_ADDRESS = "https://" + IAM_ENDPOINT + "/v3/auth/tokens"; private static final String IAM_BODY = "{\"auth\": {\"identity\": {\"methods\": [\"password\"],\"password\": {\"user\": " + "{\"name\": \"" + NAME + "\",\"password\": \"" + PASSWORD + "\",\"domain\": {\"name\": \"" + DOMAIN_NAME + "\"}}}}," + "\"scope\": {\"project\": {\"id\": \"" + PROJECT_ID + "\"}}}}"; private static final Map tokenCache = new HashMap<>(); private static final Map expireTimeCache = new HashMap<>(); public static void main(String[] args) { try { PublishService publishService = new PublishService(); CloudEvent cloudEvent = publishService.buildCloudEvent(SOURCE); publishService.publish(cloudEvent); } catch (Exception exception) { exception.printStackTrace(); } } /** * 获取token * * @param userName IAM账户用户名 * @param domainName IAM账户domain用户名 * @throws Exception */ public String getToken(String userName, String domainName) throws Exception { synchronized(expireTimeCache) { String cacheKey = domainName + userName; LocalDateTime expireTime = expireTimeCache.get(cacheKey); if (expireTime != null && tokenCache.get(cacheKey) != null) { LocalDateTime curTime = LocalDateTime.now().minusMinutes(5); if (curTime.isBefore(expireTime)) { return tokenCache.get(cacheKey); } } Map headers = new HashMap<>(); HttpResponse postResponse = getPostResponse(IAM_ADDRESS, headers, IAM_BODY); Header[] allHeaders = postResponse.getAllHeaders(); HttpEntity entity = postResponse.getEntity(); if (entity != null) { String entityString = EntityUtils.toString(entity, "UTF-8"); JSONObject jsonObject = JSONObject.parseObject(entityString); DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss"); String[] split = jsonObject.getJSONObject("token").getString("expires_at").split("\\."); expireTimeCache.put(cacheKey, LocalDateTime.parse(split[0], dateTimeFormatter)); } List
collect = Arrays.stream(allHeaders).filter(header -> header.getName().equals("X-Subject-Token")).collect(Collectors.toList()); String token = collect.get(0).getValue(); tokenCache.put(cacheKey, token); return token; } } /** * 推送CloudEvents事件到EG-engine * * @param cloudEvent * @throws Exception */ public void publish(CloudEvent cloudEvent) throws Exception { String body = buildBody(cloudEvent); Map headers = new HashMap<>(); headers.put("X-Auth-Token", getToken(DOMAIN_NAME, NAME)); HttpEntity resEntity = getPostResponse(URL, headers, body).getEntity(); if (resEntity != null) { System.out.println(System.getProperty("line.separator") + EntityUtils.toString(resEntity, "UTF-8")); } } /** * 构建CloudEvents实体 * * @param source 事件源名称 * @return CloudEvents实体 */ private CloudEvent buildCloudEvent(String source) { io.cloudevents.core.v1.CloudEventBuilder cloudEventBuilder = CloudEventBuilder.v1() .withId(UUID.randomUUID().toString()) .withSource(URI.create(source)) .withType(JsonFormat.CONTENT_TYPE) .withTime(OffsetDateTime.now()); return cloudEventBuilder.build(); } private static String buildBody(CloudEvent cloudEvent) { JsonFormat jsonFormat = ((JsonFormat) Objects.requireNonNull(EventFormatProvider.getInstance() .resolveFormat("application/cloudevents+json"))).withForceNonJsonDataToString(); EventFormatProvider.getInstance().registerFormat(jsonFormat); return "{\"events\": [" + new String(jsonFormat.serialize(cloudEvent)) + "]}"; } /** * 使用指定的headers和 body进行https请求 * * @param headers 请求headers * @param body 请求体 * @return * @throws Exception */ private HttpResponse getPostResponse(String url, Map headers, String body) throws Exception { CloseableHttpClient client = null; SSLConnectionSocketFactory scsf = new SSLConnectionSocketFactory( SSLContexts.custom().loadTrustMaterial(null, new TrustSelfSignedStrategy()).build(), NoopHostnameVerifier.INSTANCE); client = HttpClients.custom().setSSLSocketFactory(scsf).build(); HttpPost httpPost = new HttpPost(url); headers.forEach(httpPost::addHeader); httpPost.addHeader("Content-Type", "application/json"); httpPost.setEntity(new StringEntity(body, "UTF-8")); return client.execute(httpPost); } } ``` 参数说明： - NAME：IAM用户名。 - PASSWORD：IAM 用户密码。 - DOMAIN_NAME：IAM domain用户名。 - IAM_ENDPOINT：IAM的终端节点，您可以从[地区和终端节点](https://developer.huaweicloud.com/endpoint?IAM)中查询服务的终端节点。 - PROJECT_ID：即项目ID，参考[API凭证](https://support.huaweicloud.com/usermanual-ca/ca_01_0002.html)，获取项目ID。 - CHANNEL_ID：参考[收集信息](https://support.huaweicloud.com/sdkreference-eg/eg-sdk-003.html)，获取通道ID。 - ENDPOINT：事件网格[访问端点](https://support.huaweicloud.com/usermanual-eg/eg-ug-034.html)，如"华北-北京四"区域，公网访问端点值为"events.cn-north-4.myhuaweicloud.com"。 - SOURCE：即事件源名称，参考[收集信息](https://support.huaweicloud.com/sdkreference-eg/eg-sdk-003.html)，获取Filter中的values值。