每次发送消息时是否需要重建 RabbitMQ 连接

Question

我有一个 Spring 3 应用程序，它通过非 RabbitMQ 接收器接收消息，处理它们并通过 RabbitMQ 转发。每次要发送消息时，都会建立一个新的 RabbitMQ 连接。这似乎有点浪费。我只是想知道这是否真的有必要，或者是否有原因不能在单例中保持连接并且只构建一次（用于多次发送）。这是发送方式：

private void send(String routingKey, String message) throws Exception { 
    String exchange = applicationConfiguration.getAMQPExchange();  
    String ipAddress = applicationConfiguration.getAMQPHost();
    String exchangeType = applicationConfiguration.getAMQPExchangeType();
    String password = applicationConfiguration.getAMQPUser();
    String user = applicationConfiguration.getAMQPPassword();
    String virtualHost = applicationConfiguration.getAMQPVirtualHost();
    String port = applicationConfiguration.getAMQPPort();

    ConnectionFactory factory = new ConnectionFactory();
    factory.setUsername(user);
    factory.setPassword(password);
    factory.setVirtualHost(virtualHost);
    factory.setPort(Integer.parseInt(port));
    factory.setHost(ipAddress);

    Connection connection = factory.newConnection();
    Channel channel = connection.createChannel();
    channel.exchangeDeclare(exchange, exchangeType);
    channel.basicPublish(exchange, routingKey, null, message.getBytes());

    log.debug(" [AMQP] Sent message with key {} : {}",routingKey, message);

    connection.close();
}

或者一个可能的单例：

public class MyConnection {
    private static MyConnection singleton = new MyConnection();
    private static Connection connection;

    private MyConnection() {
        ConnectionFactory factory = new ConnectionFactory();
        String exchange = applicationConfiguration.getAMQPExchange();  
        String ipAddress = applicationConfiguration.getAMQPHost();
        String exchangeType = applicationConfiguration.getAMQPExchangeType();
        String password = applicationConfiguration.getAMQPUser();
        String user = applicationConfiguration.getAMQPPassword();
        String virtualHost = applicationConfiguration.getAMQPVirtualHost();
        String port = applicationConfiguration.getAMQPPort();

        try {
            factory.setUsername(user);
            factory.setPassword(password);
            factory.setVirtualHost(virtualHost);
            factory.setPort(Integer.parseInt(port));
            factory.setHost(ipAddress);
            connection = factory.newConnection();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static Connection getInstance( ) {
        return connection;
    }
}

Answer 1

连接可以是单例的，您可以共享它以进行多次发送。 频道应该是一个线程。

你的代码可能是：

private void send(String routingKey, String message) throws Exception { 
     Connection connection = MyConnection().getInstance();

    Channel channel = connection.createChannel();
    channel.exchangeDeclare(exchange, exchangeType);
    channel.basicPublish(exchange, routingKey, null, message.getBytes());
    log.debug(" [AMQP] Sent message with key {} : {}",routingKey, message);
    channel.close();
}

您可以决定为每次发布创建和销毁一个频道，或者为您的线程创建它并始终重复使用同一个频道。

编辑** 为了创建一个 sigleton 在这里阅读： http://javarevisited.blogspot.it/2012/12/how-to-create-thread-safe-singleton-in-java-example.html

public class MySingletonConnection{
    private static final MySingletonConnection INSTANCE = new MySingletonConnection();
    private Connection myConnection;
    private Singleton(){ 
      // here you can init your connection parameter
    }

    public static MySingletonConnection getInstance(){
        return INSTANCE;
    }

 public Connection getConnection( ) {
    return connection;
}
}

这是创建单例的一种方法

private void send(String routingKey, String message) throws Exception { 
     Connection connection = MySingletonConnection().getInstance().getConnection();