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<title>6.&nbsp;Dead-Letter Queue Processing</title><link rel="stylesheet" type="text/css" href="css/manual-multipage.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><link rel="home" href="multi_spring-cloud-stream-binder-rabbit.html" title="Spring Cloud Stream RabbitMQ Binder Reference Guide"><link rel="up" href="multi__reference_guide.html" title="Part&nbsp;I.&nbsp;Reference Guide"><link rel="prev" href="multi_rabbit-error-channels.html" title="5.&nbsp;Error Channels"><link rel="next" href="multi__partitioning_with_the_rabbitmq_binder.html" title="7.&nbsp;Partitioning with the RabbitMQ Binder"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">6.&nbsp;Dead-Letter Queue Processing</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="multi_rabbit-error-channels.html">Prev</a>&nbsp;</td><th width="60%" align="center">Part&nbsp;I.&nbsp;Reference Guide</th><td width="20%" align="right">&nbsp;<a accesskey="n" href="multi__partitioning_with_the_rabbitmq_binder.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a name="rabbit-dlq-processing" href="#rabbit-dlq-processing"></a>6.&nbsp;Dead-Letter Queue Processing</h2></div></div></div><p>Because you cannot anticipate how users would want to dispose of dead-lettered messages, the framework does not provide any standard mechanism to handle them.
If the reason for the dead-lettering is transient, you may wish to route the messages back to the original queue.
However, if the problem is a permanent issue, that could cause an infinite loop.
The following Spring Boot application shows an example of how to route those messages back to the original queue but moves them to a third <span class="quote">&#8220;<span class="quote">parking lot</span>&#8221;</span> queue after three attempts.
The second example uses the <a class="link" href="https://www.rabbitmq.com/blog/2015/04/16/scheduling-messages-with-rabbitmq/" target="_top">RabbitMQ Delayed Message Exchange</a> to introduce a delay to the re-queued message.
In this example, the delay increases for each attempt.
These examples use a <code class="literal">@RabbitListener</code> to receive messages from the DLQ.
You could also use <code class="literal">RabbitTemplate.receive()</code> in a batch process.</p><p>The examples assume the original destination is <code class="literal">so8400in</code> and the consumer group is <code class="literal">so8400</code>.</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_non_partitioned_destinations" href="#_non_partitioned_destinations"></a>6.1&nbsp;Non-Partitioned Destinations</h2></div></div></div><p>The first two examples are for when the destination is <span class="strong"><strong>not</strong></span> partitioned:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@SpringBootApplication</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> ReRouteDlqApplication {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String ORIGINAL_QUEUE = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"so8400in.so8400"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String DLQ = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".dlq"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String PARKING_LOT = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".parkingLot"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_RETRIES_HEADER = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-retries"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> main(String[] args) <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">throws</span> Exception {
ConfigurableApplicationContext context = SpringApplication.run(ReRouteDlqApplication.<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span>, args);
System.out.println(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Hit enter to terminate"</span>);
System.in.read();
context.close();
}
<em><span class="hl-annotation" style="color: gray">@Autowired</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> RabbitTemplate rabbitTemplate;
<em><span class="hl-annotation" style="color: gray">@RabbitListener(queues = DLQ)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> rePublish(Message failedMessage) {
Integer retriesHeader = (Integer) failedMessage.getMessageProperties().getHeaders().get(X_RETRIES_HEADER);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader == null) {
retriesHeader = Integer.valueOf(<span class="hl-number">0</span>);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader &lt; <span class="hl-number">3</span>) {
failedMessage.getMessageProperties().getHeaders().put(X_RETRIES_HEADER, retriesHeader + <span class="hl-number">1</span>);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(ORIGINAL_QUEUE, failedMessage);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">else</span> {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(PARKING_LOT, failedMessage);
}
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> Queue parkingLot() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> Queue(PARKING_LOT);
}
}</pre><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@SpringBootApplication</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> ReRouteDlqApplication {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String ORIGINAL_QUEUE = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"so8400in.so8400"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String DLQ = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".dlq"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String PARKING_LOT = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".parkingLot"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_RETRIES_HEADER = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-retries"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String DELAY_EXCHANGE = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"dlqReRouter"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> main(String[] args) <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">throws</span> Exception {
ConfigurableApplicationContext context = SpringApplication.run(ReRouteDlqApplication.<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span>, args);
System.out.println(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Hit enter to terminate"</span>);
System.in.read();
context.close();
}
<em><span class="hl-annotation" style="color: gray">@Autowired</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> RabbitTemplate rabbitTemplate;
<em><span class="hl-annotation" style="color: gray">@RabbitListener(queues = DLQ)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> rePublish(Message failedMessage) {
Map&lt;String, Object&gt; headers = failedMessage.getMessageProperties().getHeaders();
Integer retriesHeader = (Integer) headers.get(X_RETRIES_HEADER);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader == null) {
retriesHeader = Integer.valueOf(<span class="hl-number">0</span>);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader &lt; <span class="hl-number">3</span>) {
headers.put(X_RETRIES_HEADER, retriesHeader + <span class="hl-number">1</span>);
headers.put(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-delay"</span>, <span class="hl-number">5000</span> * retriesHeader);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(DELAY_EXCHANGE, ORIGINAL_QUEUE, failedMessage);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">else</span> {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(PARKING_LOT, failedMessage);
}
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> DirectExchange delayExchange() {
DirectExchange exchange = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> DirectExchange(DELAY_EXCHANGE);
exchange.setDelayed(true);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> exchange;
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> Binding bindOriginalToDelay() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> BindingBuilder.bind(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> Queue(ORIGINAL_QUEUE)).to(delayExchange()).with(ORIGINAL_QUEUE);
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> Queue parkingLot() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> Queue(PARKING_LOT);
}
}</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_partitioned_destinations" href="#_partitioned_destinations"></a>6.2&nbsp;Partitioned Destinations</h2></div></div></div><p>With partitioned destinations, there is one DLQ for all partitions. We determine the original queue from the headers.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_republishtodlqfalse" href="#_republishtodlqfalse"></a>6.2.1&nbsp;<code class="literal">republishToDlq=false</code></h3></div></div></div><p>When <code class="literal">republishToDlq</code> is <code class="literal">false</code>, RabbitMQ publishes the message to the DLX/DLQ with an <code class="literal">x-death</code> header containing information about the original destination, as shown in the following example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@SpringBootApplication</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> ReRouteDlqApplication {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String ORIGINAL_QUEUE = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"so8400in.so8400"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String DLQ = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".dlq"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String PARKING_LOT = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".parkingLot"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_DEATH_HEADER = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-death"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_RETRIES_HEADER = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-retries"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> main(String[] args) <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">throws</span> Exception {
ConfigurableApplicationContext context = SpringApplication.run(ReRouteDlqApplication.<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span>, args);
System.out.println(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Hit enter to terminate"</span>);
System.in.read();
context.close();
}
<em><span class="hl-annotation" style="color: gray">@Autowired</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> RabbitTemplate rabbitTemplate;
<em><span class="hl-annotation" style="color: gray">@SuppressWarnings("unchecked")</span></em>
<em><span class="hl-annotation" style="color: gray">@RabbitListener(queues = DLQ)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> rePublish(Message failedMessage) {
Map&lt;String, Object&gt; headers = failedMessage.getMessageProperties().getHeaders();
Integer retriesHeader = (Integer) headers.get(X_RETRIES_HEADER);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader == null) {
retriesHeader = Integer.valueOf(<span class="hl-number">0</span>);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader &lt; <span class="hl-number">3</span>) {
headers.put(X_RETRIES_HEADER, retriesHeader + <span class="hl-number">1</span>);
List&lt;Map&lt;String, ?&gt;&gt; xDeath = (List&lt;Map&lt;String, ?&gt;&gt;) headers.get(X_DEATH_HEADER);
String exchange = (String) xDeath.get(<span class="hl-number">0</span>).get(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"exchange"</span>);
List&lt;String&gt; routingKeys = (List&lt;String&gt;) xDeath.get(<span class="hl-number">0</span>).get(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"routing-keys"</span>);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(exchange, routingKeys.get(<span class="hl-number">0</span>), failedMessage);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">else</span> {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(PARKING_LOT, failedMessage);
}
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> Queue parkingLot() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> Queue(PARKING_LOT);
}
}</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_republishtodlqtrue" href="#_republishtodlqtrue"></a>6.2.2&nbsp;<code class="literal">republishToDlq=true</code></h3></div></div></div><p>When <code class="literal">republishToDlq</code> is <code class="literal">true</code>, the republishing recoverer adds the original exchange and routing key to headers, as shown in the following example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@SpringBootApplication</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> ReRouteDlqApplication {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String ORIGINAL_QUEUE = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"so8400in.so8400"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String DLQ = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".dlq"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String PARKING_LOT = ORIGINAL_QUEUE + <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">".parkingLot"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_RETRIES_HEADER = <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"x-retries"</span>;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_ORIGINAL_EXCHANGE_HEADER = RepublishMessageRecoverer.X_ORIGINAL_EXCHANGE;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">final</span> String X_ORIGINAL_ROUTING_KEY_HEADER = RepublishMessageRecoverer.X_ORIGINAL_ROUTING_KEY;
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">static</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> main(String[] args) <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">throws</span> Exception {
ConfigurableApplicationContext context = SpringApplication.run(ReRouteDlqApplication.<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span>, args);
System.out.println(<span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"Hit enter to terminate"</span>);
System.in.read();
context.close();
}
<em><span class="hl-annotation" style="color: gray">@Autowired</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">private</span> RabbitTemplate rabbitTemplate;
<em><span class="hl-annotation" style="color: gray">@RabbitListener(queues = DLQ)</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">void</span> rePublish(Message failedMessage) {
Map&lt;String, Object&gt; headers = failedMessage.getMessageProperties().getHeaders();
Integer retriesHeader = (Integer) headers.get(X_RETRIES_HEADER);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader == null) {
retriesHeader = Integer.valueOf(<span class="hl-number">0</span>);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">if</span> (retriesHeader &lt; <span class="hl-number">3</span>) {
headers.put(X_RETRIES_HEADER, retriesHeader + <span class="hl-number">1</span>);
String exchange = (String) headers.get(X_ORIGINAL_EXCHANGE_HEADER);
String originalRoutingKey = (String) headers.get(X_ORIGINAL_ROUTING_KEY_HEADER);
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(exchange, originalRoutingKey, failedMessage);
}
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">else</span> {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">this</span>.rabbitTemplate.send(PARKING_LOT, failedMessage);
}
}
<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> Queue parkingLot() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> Queue(PARKING_LOT);
}
}</pre></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="multi_rabbit-error-channels.html">Prev</a>&nbsp;</td><td width="20%" align="center"><a accesskey="u" href="multi__reference_guide.html">Up</a></td><td width="40%" align="right">&nbsp;<a accesskey="n" href="multi__partitioning_with_the_rabbitmq_binder.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">5.&nbsp;Error Channels&nbsp;</td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud-stream-binder-rabbit.html">Home</a></td><td width="40%" align="right" valign="top">&nbsp;7.&nbsp;Partitioning with the RabbitMQ Binder</td></tr></table></div></body></html>
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