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update kafka-questions-01.md

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docs/high-performance/message-queue/kafka-questions-01.md
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@ -277,9 +277,9 @@ public long nextBackOff() {
``` ```
那么这个 getMaxAttempts 的值又是多少呢？回到最开始，当执行出错会进入 DefaultErrorHandler 。DefaultErrorHandler 默认的构造函数是： 那么这个 getMaxAttempts 的值又是多少呢？回到最开始，当执行出错会进入 DefaultErrorHandler 。DefaultErrorHandler 默认的构造函数是：
```Java ```Java
public DefaultErrorHandler() { public DefaultErrorHandler() {
this(null, SeekUtils.DEFAULT_BACK_OFF); this(null, SeekUtils.DEFAULT_BACK_OFF);
} }
``` ```
SeekUtils.DEFAULT_BACK_OFF 定义的是 SeekUtils.DEFAULT_BACK_OFF 定义的是
```Java ```Java
@ -297,21 +297,21 @@ DEFAULT_MAX_FAILURES 的值是10，currentAttempts从0到9，所以总共会执
spring kafka 中只需要加上 `@DltHandler` 注解即可将重试失败的消息推到死信队列，死信队列的topic是在原 topic 后加上 '.DLT'。然后开启新的消费者消费死信队列即可。 spring kafka 中只需要加上 `@DltHandler` 注解即可将重试失败的消息推到死信队列，死信队列的topic是在原 topic 后加上 '.DLT'。然后开启新的消费者消费死信队列即可。
```Java ```Java
@DltHandler @DltHandler
@KafkaListener(topics = {KafkaConst.TEST_TOPIC}, groupId = "apple") @KafkaListener(topics = {KafkaConst.TEST_TOPIC}, groupId = "apple")
private void customer(String message) { private void customer(String message) {
log.info("kafka customer:{}", message); log.info("kafka customer:{}", message);
Integer n = Integer.parseInt(message); Integer n = Integer.parseInt(message);
if (n % 5 == 0) { if (n % 5 == 0) {
throw new RuntimeException(); throw new RuntimeException();
}
System.out.println(n);
} }
System.out.println(n);
}
@KafkaListener(topics = {KafkaConst.TEST_TOPIC + ".DLT"}, groupId = "apple") @KafkaListener(topics = {KafkaConst.TEST_TOPIC + ".DLT"}, groupId = "apple")
private void delCustomer(String message) { private void delCustomer(String message) {
// //
} }
``` ```
## 如何自定义重试次数，以及时间间隔 ## 如何自定义重试次数，以及时间间隔
"......，未完待续。" "......，未完待续。"