rabbitmq 客户端 AMQP.BasicProperties 如何设置 Headers？

Question

My Delivery object has BasicProperties.But inside the basicproprieties headers are null.I need to add a value to headers.I used builder pattern for this becourse of there don't have setter.

                Integer retryIndex = 1;

                if (delivery.getProperties().getHeaders() == null) {
                    delivery.getProperties().builder().headers(new HashMap<>()).build();
                }

                if (delivery.getProperties().getHeaders().containsKey(KEY_RETRY_COUNT)){
                    retryIndex = (Integer) delivery.getProperties().getHeaders().get(KEY_RETRY_COUNT);
                    retryIndex++;
                }

                delivery.getProperties().getHeaders().put(KEY_RETRY_COUNT, retryIndex);

when i'm run the code second if condition if (delivery.getProperties().getHeaders().containsKey(KEY_RETRY_COUNT)) getting nullPointErexception. some one can help on this.

Answer 1

    Delivery del = null;

                    if (delivery.getProperties().getHeaders() == null) {
                        Map<String, Object> header = new HashMap<>();
                        header.put(KEY_RETRY_COUNT, retryIndex);
                        delivery.getProperties().builder().headers(header).build();

                        del = new Delivery(delivery.getEnvelope(),
                                           new AMQP.BasicProperties().builder().headers(header).build(),
                                           delivery.getBody());
}

Here i create a new Delivery object and use the constructor to set the properties.