向 Azure 服务总线队列发送消息并从中接收消息 (JavaScript)Send messages to and receive messages from Azure Service Bus queues (JavaScript)

本教程介绍如何使用 JavaScript 程序中的 @azure/service-bus 包向服务总线队列发送消息并从中接收消息。In this tutorial, you learn how to use the @azure/service-bus package in a JavaScript program to send messages to and receive messages from a Service Bus queue.

先决条件Prerequisites

备注

使用节点包管理器 (NPM) 安装包Use Node Package Manager (NPM) to install the package

若要安装服务总线的 npm 包，请打开路径中包含 npm 的命令提示符，将目录更改为要包含示例的文件夹，然后运行此命令To install the npm package for Service Bus, open a command prompt that has npm in its path, change the directory to the folder where you want to have your samples and then run this command.

npm install @azure/service-bus

向队列发送消息Send messages to a queue

以下示例代码演示如何向队列发送消息。The following sample code shows you how to send a message to a queue.

  1. 打开偏好的编辑器，例如 Visual Studio Code。Open your favorite editor, such as Visual Studio Code.

  2. 创建一个名为 send.js 的文件，并将下面的代码粘贴到其中。Create a file called send.js and paste the below code into it. 此代码将向队列发送一条消息。This code will send a message to your queue. 消息具有标签（科学家）和正文（爱因斯坦）。The message has a label (Scientist) and body (Einstein).

    const { ServiceBusClient } = require("@azure/service-bus");

// connection string to your Service Bus namespace
const connectionString = "<CONNECTION STRING TO SERVICE BUS NAMESPACE>"

// name of the queue
const queueName = "<QUEUE NAME>"

const messages = [
    { body: "Albert Einstein" },
    { body: "Werner Heisenberg" },
    { body: "Marie Curie" },
    { body: "Steven Hawking" },
    { body: "Isaac Newton" },
    { body: "Niels Bohr" },
    { body: "Michael Faraday" },
    { body: "Galileo Galilei" },
    { body: "Johannes Kepler" },
    { body: "Nikolaus Kopernikus" }
 ];

async function main() {
    // create a Service Bus client using the connection string to the Service Bus namespace
    const sbClient = new ServiceBusClient(connectionString);

    // createSender() can also be used to create a sender for a topic.
    const sender = sbClient.createSender(queueName);

    try {
        // Tries to send all messages in a single batch.
        // Will fail if the messages cannot fit in a batch.
        // await sender.sendMessages(messages);

        // create a batch object
        let batch = await sender.createMessageBatch(); 
        for (let i = 0; i < messages.length; i++) {
            // for each message in the array            

            // try to add the message to the batch
            if (!batch.tryAddMessage(messages[i])) {            
                // if it fails to add the message to the current batch
                // send the current batch as it is full
                await sender.sendMessages(batch);

                // then, create a new batch 
                batch = await sender.createMessageBatch();

                // now, add the message failed to be added to the previous batch to this batch
                if (!batch.tryAddMessage(messages[i])) {
                    // if it still can't be added to the batch, the message is probably too big to fit in a batch
                    throw new Error("Message too big to fit in a batch");
                }
            }
        }

        // Send the last created batch of messages to the queue
        await sender.sendMessages(batch);

        console.log(`Sent a batch of messages to the queue: ${queueName}`);

        // Close the sender
        await sender.close();
    } finally {
        await sbClient.close();
    }
}

// call the main function
main().catch((err) => {
    console.log("Error occurred: ", err);
    process.exit(1);
 });

  3. 将 <CONNECTION STRING TO SERVICE BUS NAMESPACE> 替换为服务总线命名空间的连接字符串。Replace <CONNECTION STRING TO SERVICE BUS NAMESPACE> with the connection string to your Service Bus namespace.

  4. 将 <QUEUE NAME> 替换为该队列的名称。Replace <QUEUE NAME> with the name of the queue.

  5. 然后，在命令提示符中运行该命令以执行此文件。Then run the command in a command prompt to execute this file.

    node send.js

  6. 你会看到以下输出。You should see the following output.

    Sent a batch of messages to the queue: myqueue

从队列接收消息Receive messages from a queue

  1. 打开你喜好的编辑器，例如 Visual Studio CodeOpen your favorite editor, such as Visual Studio Code

  2. 创建名为 receive.js 的文件，然后将以下代码粘贴到其中。Create a file called receive.js and paste the following code into it.

    const { delay, ServiceBusClient, ServiceBusMessage } = require("@azure/service-bus");

// connection string to your Service Bus namespace
const connectionString = "<CONNECTION STRING TO SERVICE BUS NAMESPACE>"

// name of the queue
const queueName = "<QUEUE NAME>"

 async function main() {
    // create a Service Bus client using the connection string to the Service Bus namespace
    const sbClient = new ServiceBusClient(connectionString);

    // createReceiver() can also be used to create a receiver for a subscription.
    const receiver = sbClient.createReceiver(queueName);

    // function to handle messages
    const myMessageHandler = async (messageReceived) => {
        console.log(`Received message: ${messageReceived.body}`);
    };

    // function to handle any errors
    const myErrorHandler = async (error) => {
        console.log(error);
    };

    // subscribe and specify the message and error handlers
    receiver.subscribe({
        processMessage: myMessageHandler,
        processError: myErrorHandler
    });

    // Waiting long enough before closing the sender to send messages
    await delay(5000);

    await receiver.close(); 
    await sbClient.close();
}    
// call the main function
main().catch((err) => {
    console.log("Error occurred: ", err);
    process.exit(1);
 });

  3. 将 <CONNECTION STRING TO SERVICE BUS NAMESPACE> 替换为服务总线命名空间的连接字符串。Replace <CONNECTION STRING TO SERVICE BUS NAMESPACE> with the connection string to your Service Bus namespace.

  4. 将 <QUEUE NAME> 替换为该队列的名称。Replace <QUEUE NAME> with the name of the queue.

  5. 然后，在命令提示符中运行命令以执行此文件。Then, run the command in a command prompt to execute this file.

    node receive.js

  6. 你会看到以下输出。You should see the following output.

    Received message: Albert Einstein
Received message: Werner Heisenberg
Received message: Marie Curie
Received message: Steven Hawking
Received message: Isaac Newton
Received message: Niels Bohr
Received message: Michael Faraday
Received message: Galileo Galilei
Received message: Johannes Kepler
Received message: Nikolaus Kopernikus

在 Azure 门户中的服务总线命名空间的“概述”页上，可看到传入和传出消息计数 。On the Overview page for the Service Bus namespace in the Azure portal, you can see incoming and outgoing message count. 可能需要等待一分钟左右，然后刷新页面才会看到最新值。You may need to wait for a minute or so and then refresh the page to see the latest values.

传入和传出消息计数

在此“概述”页上选择队列，导航到“服务总线队列”页面 。Select the queue on this Overview page to navigate to the Service Bus Queue page. 还可在此页上看到传入和传出消息计数 。You see the incoming and outgoing message count on this page too. 还可看到其他信息，如队列的当前大小、最大大小和活动消息计数等 。You also see other information such as the current size of the queue, maximum size, active message count, and so on.

队列详细信息

后续步骤Next steps

请参阅以下文档和示例：See the following documentation and samples: