Refactor messaging sample and readme for Spring Cloud Messaging(Azure#20214)

Author: wujack778

sdk/spring/azure-spring-boot-samples/azure-spring-cloud-sample-messaging/README.md

@@ -1,15 +1,67 @@
-# Azure Spring Cloud Messaging Sample client library for Java
+# Spring Cloud Azure Messaging Sample shared library for Java
 
 ## Key concepts
+
+This code sample demonstrates how to use [AzureMessageListener.java][annotation-azure-message-listener] to listen to events from Event Hubs.
+
 ## Getting started
 
+Running this sample will be charged by Azure. You can check the usage and bill at 
+[this link][azure-account].
+
 ### Prerequisites
 - [Environment checklist][environment_checklist]
 
+### Create Azure resources
+
+1.  Create [Azure Event Hubs Namespace][create-event-hubs-namespace].
+    Please note `Basic` tier is unsupported. After creating the Azure Event Hub, you
+    can create your own Consumer Group or use the default `$Default` Consumer Group.
+    
+1.  Create [Azure Event Hub][create-event-hub-instance] and named `event-hub-name`.
+
+1.  Create [Azure Storage][create-azure-storage] for checkpoint use.
+
 ## Examples
+
+1. Update [application.yaml][application.yaml].
+    ```yaml
+    spring:
+      cloud:
+        azure:
+          eventhub:
+            connection-string: [eventhub-namespace-connection-string]
+            checkpoint-storage-account: [checkpoint-storage-account]
+            checkpoint-access-key: [checkpoint-access-key]
+            checkpoint-container: [checkpoint-container]
+    ```
+
+1.  Run the `mvn spring-boot:run` in the root of the code sample to get the app running.
+
+1.  Send a POST request
+
+        $ curl -H "Content-type: application/json" -X POST http://localhost:8080/messages -d "{\"name\":\"hello\"}"
+
+1.  Verify in your app’s logs that a similar message was posted:
+
+        New message received: 'User{name='hello'}'
+
+1.  Delete the resources on [Azure Portal][azure-portal] to avoid unexpected charges.
+
 ## Troubleshooting
+
 ## Next steps
+
 ## Contributing
 
+
 <!-- LINKS -->
+
+[azure-account]: https://azure.microsoft.com/account/
+[azure-portal]: https://ms.portal.azure.com/
+[create-event-hubs-namespace]: https://docs.microsoft.com/azure/event-hubs/event-hubs-create#create-an-event-hubs-namespace
+[create-event-hub-instance]: https://docs.microsoft.com/azure/event-hubs/event-hubs-create#create-an-event-hub
+[create-azure-storage]: https://docs.microsoft.com/azure/storage/ 
+[annotation-azure-message-listener]: https://github.com/Azure/azure-sdk-for-java/blob/master/sdk/spring/azure-spring-cloud-messaging/src/main/java/com/azure/spring/messaging/annotation/AzureMessageListener.java
 [environment_checklist]: https://github.com/Azure/azure-sdk-for-java/blob/master/sdk/spring/ENVIRONMENT_CHECKLIST.md#ready-to-run-checklist
+[application.yaml]: https://github.com/Azure/azure-sdk-for-java/blob/master/sdk/spring/azure-spring-boot-samples/azure-spring-cloud-sample-eventhubs-operation/src/main/resources/application.yaml

sdk/spring/azure-spring-boot-samples/azure-spring-cloud-sample-messaging/src/main/java/com/azure/spring/sample/messaging/WebController.java

@@ -17,8 +17,8 @@
 @RestController
 public class WebController {
 
-    private static final String EVENT_HUB_NAME = "eventhub1";
-    private static final String CONSUMER_GROUP = "cg1";
+    private static final String EVENT_HUB_NAME = "event-hub-name";
+    private static final String CONSUMER_GROUP = "$Default";
 
     @Autowired
     EventHubOperation eventHubOperation;

sdk/spring/azure-spring-boot-samples/azure-spring-cloud-sample-messaging/src/main/resources/application.yaml

@@ -0,0 +1,8 @@
+spring:
+  cloud:
+    azure:
+      eventhub:
+        connection-string: [eventhub-namespace-connection-string]
+        checkpoint-storage-account: [checkpoint-storage-account]
+        checkpoint-access-key: [checkpoint-access-key]
+        checkpoint-container: [checkpoint-container]