我正在尝试实现一个 Java 应用程序，用于向 Azure 服务总线队列发送消息和从 Azure 服务总线队列接收消息。与门户的连接和消息的发送进展顺利，但在接收消息并获取消息正文内容时，某些变量缺少其值“null”。我该如何解决这个问题？
这是我用来发送和接收消息的代码:
CompletableFuture<Void> sendMessagesAsync(QueueClient sendClient) {
List<HashMap<String, String>> data =
GSON.fromJson(
"[" +
"{'Device ID' = 'FieldPanel_L1'},"+
"{'Sensor1name' = 'FieldPanel_SL1', 'value1' = '0', 'Location of Sensor1 X' = '0.0', 'Location of sensor1 Y' = '0.0'}," +
"{'Sensor2name' = 'FieldPanel_SL2', 'value2' = '0', 'Location of Sensor2 X' = '20.0', 'Location of sensor2 Y' = '0.0'},"+
"{'Sensor3name' = 'FieldPanel_SL3', 'value3' = '0', 'Location of Sensor3 X' = '40.0', 'Location of sensor3 Y' = '0.0'}"+
"]",
new TypeToken<List<HashMap<String, String>>>() {}.getType());
List<CompletableFuture> tasks = new ArrayList<>();
for (int i = 0; i < data.size(); i++) {
final String messageId = Integer.toString(i);
Message message = new Message(GSON.toJson(data.get(i), Map.class).getBytes(UTF_8));
message.setContentType("application/json");
message.setLabel("FieldPanel");
message.setMessageId(messageId);
message.setTimeToLive(Duration.ofMinutes(2));
System.out.printf("\nSending Message: Id = %s", message.getMessageId());
tasks.add(
sendClient.sendAsync(message).thenRunAsync(() -> {
System.out.printf("\n\tAcknowledged Message: Id = %s", message.getMessageId());
}));
}
return CompletableFuture.allOf(tasks.toArray(new CompletableFuture<?>[tasks.size()]));
} // Method sendMessageAsync()
void registerReceiver(QueueClient queueClient, ExecutorService executorService) throws Exception {
// register the RegisterMessageHandler callback with executor service
queueClient.registerMessageHandler(new IMessageHandler() {
// callback invoked when the message handler loop has obtained a message
public CompletableFuture<Void> onMessageAsync(IMessage message) {
// received message is passed to callback
if (message.getLabel() != null &&
message.getContentType() != null &&
message.getLabel().contentEquals("FieldPanel") &&
message.getContentType().contentEquals("application/json")) {
byte[] body = message.getBody();
Map fieldPanel = GSON.fromJson(new String(body, UTF_8), Map.class);
System.out.printf("\n\t\t\tMessage received: \n\t\t\t\t\tMessageId = %s, \n\t\t\t\t\tSequenceNumber = %s, \n\t\t\t\t\tEnqueuedTimeUtc = %s," +
"\n\t\t\t\t\tExpiresAtUtc = %s, \n\t\t\t\t\tContentType = \"%s\", \n\t\t\t\t\tContent: [ Sensor 1 Name = %s, Value = %s, Location of Sensor1 X = %s, Location of sensor1 Y = %s, Sensor 2 Name = %s, Value = %s, Location of Sensor2 X = %s, Location of sensor2 Y = %s, Sensor 3 Name = %s, Value = %s, Location of Sensor3 X = %s, Location of sensor3 Y = %s ]\n",
message.getMessageId(),
message.getSequenceNumber(),
message.getEnqueuedTimeUtc(),
message.getExpiresAtUtc(),
message.getContentType(),
fieldPanel != null ? fieldPanel.get("Sensor1name") : "ERROR" ,
fieldPanel != null ? fieldPanel.get("value1") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of Sensor1 X") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of sensor1 Y") : "ERROR",
fieldPanel != null ? fieldPanel.get("Sensor2name") : "ERROR",
fieldPanel != null ? fieldPanel.get("value2") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of Sensor2 X") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of sensor2 Y") : "ERROR",
fieldPanel != null ? fieldPanel.get("Sensor3name") : "ERROR",
fieldPanel != null ? fieldPanel.get("value3") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of Sensor3 X") : "ERROR",
fieldPanel != null ? fieldPanel.get("Location of sensor3 Y") : "ERROR");
} //Message Body
return CompletableFuture.completedFuture(null);
}
// callback invoked when the message handler has an exception to report
public void notifyException(Throwable throwable, ExceptionPhase exceptionPhase) {
System.out.printf(exceptionPhase + "-" + throwable.getMessage());}
}, new MessageHandlerOptions(1, true,Duration.ofMinutes(1)),executorService);
} // Method registerReceiver()
这是我在控制台上收到的消息输出:
Message received:
MessageId = 1,
SequenceNumber = 15,
EnqueuedTimeUtc = 2019-07-22T08:40:29.161Z,
ExpiresAtUtc = 2019-07-22T08:42:29.161Z,
ContentType = "application/json",
Content: [ Sensor 1 Name = FieldPanel_SL1, Value = 0, Location of Sensor1 X = 0.0, Location of sensor1 Y = 0.0, Sensor 2 Name = null, Value = null, Location of Sensor2 X = null, Location of sensor2 Y = null, Sensor 3 Name = null, Value = null, Location of Sensor3 X = null, Location of sensor3 Y = null ]
最佳答案
我检查了您的代码，发现您得到的输出是正确的。
在您的代码中，您创建一个包含 4 个 HashMap 的列表。将发送 4 条消息。每条消息都是设备的部分信息。
所以，在您收到的消息中，您每次只能获得一份。
我猜json中的所有信息都应该是针对一台设备的。您实际上想在一封邮件中发送它们。
以下是可能满足您要求的示例:
public class ServicebusBasicTest {
static Gson GSON = new Gson();
static String connectionString = "Endpoint=sb://ja**78.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=73**U=";
static CompletableFuture<Void> sendMessagesAsync(QueueClient sendClient) {
List<HashMap<String, String>> data =
GSON.fromJson(
"[" +
"{'Device ID' = 'FieldPanel_L1'}," +
"{'Sensor1name' = 'FieldPanel_SL1', 'value1' = '0', 'Location of Sensor1 X' = '0.0', 'Location of sensor1 Y' = '0.0'}," +
"{'Sensor2name' = 'FieldPanel_SL2', 'value2' = '0', 'Location of Sensor2 X' = '20.0', 'Location of sensor2 Y' = '0.0'}," +
"{'Sensor3name' = 'FieldPanel_SL3', 'value3' = '0', 'Location of Sensor3 X' = '40.0', 'Location of sensor3 Y' = '0.0'}" +
"]",
new TypeToken<List<HashMap<String, String>>>() {}.getType()
);
List<CompletableFuture> tasks = new ArrayList<>();
final String messageId = Integer.toString(1);
Message message = new Message(GSON.toJson(data, List.class).getBytes(Charset.forName("UTF-8")));
message.setContentType("application/json");
message.setLabel("FieldPanel");
message.setMessageId(messageId);
message.setTimeToLive(Duration.ofMinutes(2));
System.out.printf("\nSending Message: Id = %s\n", message.getMessageId());
tasks.add(
sendClient.sendAsync(message).thenRunAsync(() -> {
System.out.printf("\nMessage Sent: Id = %s\n", message.getMessageId());
}));
return CompletableFuture.allOf(tasks.toArray(new CompletableFuture<?>[tasks.size()]));
}
static void registerReceiver(QueueClient queueClient, ExecutorService executorService) throws Exception {
queueClient.registerMessageHandler(new IMessageHandler() {
public CompletableFuture<Void> onMessageAsync(IMessage message) {
if (message.getLabel() != null &&
message.getContentType() != null &&
message.getLabel().contentEquals("FieldPanel") &&
message.getContentType().contentEquals("application/json")) {
List<HashMap<String, String>> fieldPanel = GSON.fromJson(new String(message.getBody(), Charset.forName("UTF-8")), new TypeToken<List<HashMap<String, String>>>() {}.getType());
System.out.printf(
"\nMessage received: \n -->MessageId = %s\n -->ContentType = %s",
message.getMessageId(),
message.getContentType()
);
System.out.print("\n -->Device info");
for ( HashMap<String,String> map: fieldPanel) {
for (Object object : map.entrySet()) {
Map.Entry entry = (Map.Entry) object;
System.out.printf("\n -----> %s : %s", entry.getKey(),entry.getValue());
}
}
System.out.println();
}
return queueClient.completeAsync(message.getLockToken());
}
public void notifyException(Throwable throwable, ExceptionPhase exceptionPhase) {
System.out.printf(exceptionPhase + "-" + throwable.getMessage());
}
},
new MessageHandlerOptions(1, false, Duration.ofSeconds(5)),
executorService
);
}
public static void main(String[] args) throws Exception{
QueueClient receiveClient = new QueueClient(new ConnectionStringBuilder(connectionString, "testqueue"), ReceiveMode.PEEKLOCK);
ExecutorService executorService = Executors.newSingleThreadExecutor();
registerReceiver(receiveClient, executorService);
QueueClient client = new QueueClient(new ConnectionStringBuilder(connectionString, "testqueue"), ReceiveMode.PEEKLOCK);
sendMessagesAsync(client).join();
Thread.sleep(5000);
client.close();
receiveClient.close();
executorService.shutdown();
}
}
控制台输出:
Sending Message: Id = 1
Message Sent: Id = 1
Message received:
-->MessageId = 1
-->ContentType = application/json
-->Device info
-----> Device ID : FieldPanel_L1
-----> Sensor1name : FieldPanel_SL1
-----> Location of sensor1 Y : 0.0
-----> Location of Sensor1 X : 0.0
-----> value1 : 0
-----> Location of Sensor2 X : 20.0
-----> Location of sensor2 Y : 0.0
-----> value2 : 0
-----> Sensor2name : FieldPanel_SL2
-----> Location of Sensor3 X : 40.0
-----> Location of sensor3 Y : 0.0
-----> value3 : 0
-----> Sensor3name : FieldPanel_SL3
关于java - 从 Azure 服务总线队列接收 NULL 消息正文内容，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/57142441/