Question

是否可以在事务中的代码下运行，因此如果在业务处理中抛出异常，我们可以回滚我们发送到队列的消息？

rabbitTemplate.convertAndSend("queue1", data);

//do some processing

rabbitTemplate.convertAndSend("queue2", data);

如果在向queueq发送消息之后出现问题但是我们无法向queue2发送消息，则需要这样做。或者如果在将消息发送到队列时发出网络或其他问题该怎么办。

Answer 1

如果此代码在侦听器容器线程（onMessage()或@RabbitListener）上运行，并且容器和模板都具有setChannelTransacted(true)，则发布（和传递）将在同一个线程中运行交易;抛出异常将导致所有内容回滚。

如果这是某个任意java类（不在容器线程上运行），那么你需要在方法运行之前启动事务...

    @Transactional
    public void send(String in) {
        this.template.convertAndSend("foo", in);
        if (in.equals("foo")) {
            throw new RuntimeException("test");
        }
        this.template.convertAndSend("bar", in);
    }

这是一个完整的Spring Boot应用程序，用于演示该功能......

@SpringBootApplication
@EnableTransactionManagement
public class So40749877Application {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(So40749877Application.class, args);
        Foo foo = context.getBean(Foo.class);
        try {
            foo.send("foo");
        }
        catch (Exception e) {}
        foo.send("bar");
        RabbitTemplate template = context.getBean(RabbitTemplate.class);
        // should not get any foos...
        System.out.println(template.receiveAndConvert("foo", 10_000));
        System.out.println(template.receiveAndConvert("bar", 10_000));
        // should be null
        System.out.println(template.receiveAndConvert("foo", 0));
        RabbitAdmin admin = context.getBean(RabbitAdmin.class);
        admin.deleteQueue("foo");
        admin.deleteQueue("bar");
        context.close();
    }

    @Bean
    public RabbitTemplate amqpTemplate(ConnectionFactory connectionFactory) {
        RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
        rabbitTemplate.setChannelTransacted(true);
        return rabbitTemplate;
    }

    @Bean
    public Queue foo() {
        return new Queue("foo");
    }

    @Bean
    public Queue bar() {
        return new Queue("bar");
    }

    @Bean
    public Foo fooBean() {
        return new Foo();
    }

    @Bean
    public PlatformTransactionManager transactionManager(ConnectionFactory connectionFactory) {
        return new RabbitTransactionManager(connectionFactory);
    }

    public static class Foo {

        @Autowired
        private RabbitTemplate template;

        @Transactional
        public void send(String in) {
            this.template.convertAndSend("foo", in);
            if (in.equals("foo")) {
                throw new RuntimeException("test");
            }
            this.template.convertAndSend("bar", in);
        }

    }

}

修改

消费者方面的交易;这通常不适用于使用Spring，因为它管理事务，但直接使用客户端时...

Connection connection = cf.createConnection(); Channel channel = connection.createChannel(true); channel.basicQos(1); channel.txSelect(); CountDownLatch latch = new CountDownLatch(1); channel.basicConsume("foo", new DefaultConsumer(channel) { @Override public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException { System.out.println(new String(body)); getChannel().txRollback(); // delivery won't be requeued; remains unacked if (envelope.isRedeliver()) { getChannel().basicAck(envelope.getDeliveryTag(), false); getChannel().txCommit(); // commit the ack so the message is removed getChannel().basicCancel(consumerTag); latch.countDown(); } else { // first time, let's requeue getChannel().basicReject(envelope.getDeliveryTag(), true); getChannel().txCommit(); // commit the reject so the message will be requeued } } }); latch.await(); channel.close(); connection.close();

注意txRollback在这种情况下什么都不做;只有ack（或拒绝）是交易的。

RabbitMQ在事务中发送消息

1 个答案: