通过MQ实现异步调用第三方接口并等待MQ获取接口返回值 代码示例

以下是一个基于Java的MQ异步调用第三方接口示例：

// 生产者代码，将请求发送到MQ
public class Producer {
    private final static String QUEUE_NAME = "third-party-api";

    public static void main(String[] argv) throws Exception {
        // 创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");

        // 创建连接
        Connection connection = factory.newConnection();

        // 创建通道
        Channel channel = connection.createChannel();

        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        // 构造请求
        String message = "http://third-party-api.com/api?param1=value1&param2=value2";

        // 发送请求
        channel.basicPublish("", QUEUE_NAME, null, message.getBytes("UTF-8"));
        System.out.println("Sent message: " + message);

        // 关闭通道和连接
        channel.close();
        connection.close();
    }
}

// 消费者代码，监听MQ消息并发送请求到第三方接口
public class Consumer {
    private final static String QUEUE_NAME = "third-party-api";

    public static void main(String[] argv) throws Exception {
        // 创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");

        // 创建连接
        Connection connection = factory.newConnection();

        // 创建通道
        Channel channel = connection.createChannel();

        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        // 创建消费者，并设置回调函数处理消息
        Consumer consumer = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String message = new String(body, "UTF-8");
                System.out.println("Received message: " + message);

                // 发送请求到第三方接口
                String response = sendRequest(message);

                // 将接口返回值发送到MQ
                channel.basicPublish("", properties.getReplyTo(), null, response.getBytes("UTF-8"));
            }
        };

        // 监听队列，自动确认消息
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

    // 发送请求到第三方接口，并等待接口返回值
    private static String sendRequest(String request) {
        // TODO: 发送请求到第三方接口，并等待接口返回值
        return "response";
    }
}

// 发送请求的代码，监听MQ返回值并返回到主线程
public class RequestSender {
    private final static String RESPONSE_QUEUE_NAME = "third-party-api-response";

    public static void main(String[] argv) throws Exception {
        // 创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");

        // 创建连接
        Connection connection = factory.newConnection();

        // 创建通道
        Channel channel = connection.createChannel();

        // 声明队列
        channel.queueDeclare(RESPONSE_QUEUE_NAME, false, false, false, null);

        // 创建消费者，并设置回调函数处理消息
        Consumer consumer = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String response = new String(body, "UTF-8");
                System.out.println("Received response: " + response);

                // 将接口返回值返回到主线程
                synchronized (this) {
                    this.notify();
                }
            }
        };

        // 监听队列，手动确认消息
        channel.basicConsume(RESPONSE_QUEUE_NAME, false, consumer);

        // 发送请求并等待返回值
        String request = "http://third-party-api.com/api?param1=value1&param2=value2";
        String correlationId = UUID.randomUUID().toString();
        AMQP.BasicProperties props = new AMQP.BasicProperties.Builder()
                .correlationId(correlationId)
                .replyTo(RESPONSE_QUEUE_NAME)
                .build();

        channel.basicPublish("", "third-party-api", props, request.getBytes("UTF-8"));

        synchronized (consumer) {
            consumer.wait();
        }

        // 关闭通道和连接
        channel.close();
        connection.close();
    }
}

说明：

1. 生产者发送请求到MQ，并设置回调队列名。
2. 消费者监听MQ消息，收到消息后发送请求到第三方接口，并将接口返回值发送到回调队列。
3. 发送者发送请求到MQ，并设置回调队列名和Correlation ID。
4. 发送者等待消费者返回接口返回值，并将接口返回值返回到主线程。