我正在使用spring批处理和kafka处理一个小批处理,它从kafka主题读取json数据,将其转换为student对象,更改值并将其发送回kafka主题。一切都很好,但我唯一的问题是,我的消费者总是从乞讨的主题阅读。我需要它来读最后一条未被消费的信息。我已经添加了这些属性:
ConsumerConfig.AUTO_OFFSET_RESET_CONFIG to earliest
ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG to false
ConsumerConfig.GROUP_ID_CONFIG to a random value
但这似乎不起作用,在消费者启动时,它处理所有的信息。有人知道怎么用Spring批和Kafka吗?这是我的密码:
batchstudent.java文件:
@SpringBootApplication
@EnableBatchProcessing
@RequiredArgsConstructor
public class BatchStudent {
public static void main(String[] args) {
SpringApplication.run(BatchStudent.class, args);
}
private final JobBuilderFactory jobBuilderFactory;
private final StepBuilderFactory stepBuilderFactory;
private final KafkaTemplate<Integer, Student> template;
private final KafkaProperties properties;
@Value("${kafka.topic.consumer}")
private String topic;
@Bean
public ItemProcessor<Student, Student> customItemProcessor() {
return new CustomProcessor();
}
@Bean
Job job() {
return this.jobBuilderFactory.get("job")
.start(start())
.incrementer(new RunIdIncrementer())
.build();
}
@Bean
KafkaItemWriter<Integer, Student> writer() {
return new KafkaItemWriterBuilder<Integer, Student>()
.kafkaTemplate(template)
.itemKeyMapper(Student::getId)
.build();
}
@Bean
public KafkaItemReader<Integer, Student> reader() {
Properties props = new Properties();
props.putAll(this.properties.buildConsumerProperties());
return new KafkaItemReaderBuilder<Integer, Student>()
.partitions(0)
.consumerProperties(props)
.name("students-consumer-reader")
.saveState(true)
.topic(topic)
.build();
}
@Bean
Step start() {
return this.stepBuilderFactory
.get("step")
.<Student, Student>chunk(10)
.writer(writer())
.processor(customItemProcessor())
.reader(reader())
.build();
}
}
应用程序yml
spring.batch.initialize-schema: always
# Conf Kafka Consumer
spring.kafka.consumer.key-deserializer: org.apache.kafka.common.serialization.IntegerDeserializer
spring.kafka.consumer.value-deserializer: org.springframework.kafka.support.serializer.JsonDeserializer
# spring.kafka.consumer.group-id: student-group
spring.kafka.consumer.properties.spring.json.trusted.packages: '*'
spring.kafka.consumer.properties.spring.json.value.default.type: com.org.model.Student
# Conf Kafka Producer
spring.kafka.producer.key-serializer: org.apache.kafka.common.serialization.IntegerSerializer
spring.kafka.producer.value-serializer: org.springframework.kafka.support.serializer.JsonSerializer
spring.kafka.producer.bootstrap-servers: localhost:9092
# Conf topics
spring.kafka.template.default-topic: producer.student
kafka.topic.consumer: consumer.student
学生.java
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Student {
Integer id;
Integer count;
}
自定义处理器.java
@NoArgsConstructor
public class CustomProcessor implements ItemProcessor<Student, Student> {
@Override
public Student process(Student studentRecieved) {
final Student studentSent = new Student();
studentSent.setId(studentRecieved.getId());
studentSent.setCount(200);
return studentSent;
}
}
谢谢你的帮助!
1条答案
按热度按时间ldioqlga1#
一切都很好,但我唯一的问题是,我的消费者总是从乞讨的主题阅读。我需要它来读最后一条未被消费的信息。
springbatch4.3引入了一种使用kafka中存储的偏移量记录的方法。我在去年的springone演讲中谈到了这个特性:springbatch4.3有什么新特性?。您可以使用setPartitionOffset在每个分区中为kafka读取器配置一个自定义的起始偏移量:
您可以在这个测试用例中找到一个完整的示例。