写在前面:2020年面试必备的Java后端进阶面试题总结了一份复习指南在Github上,内容详细,图文并茂,有需要学习的朋友可以Star一下!
GitHub地址:https://github.com/abel-max/Java-Study-Note/tree/master
一.springboot自动配置方式整合kafka:
springboot提供自动配置整合kafka的方式,需要做一下步骤:
- 引入kafka依赖包:
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>2.2.7.RELEASE</version>
</dependency>
2.在springboot配置中加入kafka相关配置,springboot启动时候会自动加载这些配置,完成链接kafka,创建producer,consumer等。
spring:
kafka:
# kafka服务地址
bootstrap-servers: 127.0.0.1:9092
# 消费者配置
consumer:
bootstrap-servers: 127.0.0.1:9092
group-id: myGroup
enable-auto-commit: true
auto-offset-reset: earliest
auto-commit-interval: 1000
max-poll-records: 10
# 生产者配置
producer:
retries: 5
batch-size: 16384
buffer-memory: 33554432
acks: 1
3.消息发送端:
@Component
public class MqProviderImpl{
@Autowired
private KafkaTemplate<String, String> kafkaTemplate;
@Override
public void sendSkMessage(String message, Properties properties) {
// 发送消息,注册一个回调事件
ListenableFuture<SendResult<String, String>> futureMessage = KafkaConfig.kafkaTemplateStatic.send("test_topic",
message);
futureMessage.addCallback(new ListenableFutureCallback<SendResult<String, String>>(){
@Override
public void onSuccess(SendResult<String, String> sendResult) {
log.info(" rev "+sendResult.getProducerRecord().value());
}
@Override
public void onFailure(Throwable ex) {
log.error(" error "+ex.getMessage());
}
});
}}
4.消息消费端:
@KafkaListener(topics = {"test_topic"})
public void receiveSkMessageInfo(ConsumerRecord<String, String> record, @Header(KafkaHeaders.RECEIVED_TOPIC) String topic, Acknowledgment ack) {
log.info(record.value());
}
以上实现是最简单的方式,但使用springboot自动配置的方式,所有配置项必须事先写好在在applicantion.yml的spring.kafka下面,试想在分布式的场景中,如果某一项发生变动,每个应用下面的配置都需要修改,这就需要将这些配置使用服务治理统一管理起来,这里就需要一种自定义配置的方式来解决。
springboot自动配置kafka是在KafkaAutoConfiguration这个类中实现的,它有一个成员KafkaProperties,这个properties中保存所有关于kafka的配置。
// 自动配置是在KafkaAutoConfiguration类实现的
@Configuration
@ConditionalOnClass(KafkaTemplate.class)
@EnableConfigurationProperties(KafkaProperties.class)
@Import({ KafkaAnnotationDrivenConfiguration.class,
KafkaStreamsAnnotationDrivenConfiguration.class })
public class KafkaAutoConfiguration {
private final KafkaProperties properties;
KafkaProperties类的注解可以看出,配置都是从yml里的spring.kafka配置读出来的
@ConfigurationProperties(prefix = "spring.kafka")
public class KafkaProperties {
二.springboot手动配置方式整合kafka,使用zk做配置中心:
在分布式的环境下,需要使用服务治理把yml里的配置统一管理起来,这里使用zookeeper来统一管理kafka的配置。如果将原有的配置放到zk中,来实现从zk上读取配置,让springboot接收到,这里就需要重新定义kafka的配置类,不能使用原有的KafkaAutoConfiguration了。
1.从zk上拉取配置,这里使用当当开源的 Config Toolkit ,还自带一个操作zk的管理界面,引入pom:
<dependency>
<groupId>com.dangdang</groupId>
<artifactId>config-toolkit</artifactId>
<version>3.3.2-RELEASE</version>
</dependency>
2.在yml中添加链接zk的配置,有这些配置才能保证应用能链接zk: `
configs:
# zk地址
address: 192.168.1.30:2181
# 保存应用配置的节点名
env: /projectx/modulex
version: 1
# zk数据组
groupdefault: groupdefault
3.下载当当的config-toolkit,访问http://localhost:8080/,加入相关配置,github上有详细说明。
- 新建一个ZKConfiguration类,实现EnvironmentAware接口,实现EnvironmentAware接口的setEnvironment可以在项目启动时设置项目的环境变量,可以在这个类中结合config-toolkit,把zk的配置加载到项目环境变量当中:
@Component
public class ZKConfiguration implements EnvironmentAware {
@Autowired
private Environment env;
private static Map<String, GeneralConfigGroup> GROUPMAP = new HashMap<>();
public ZKConfiguration() {
}
// 加载zk的基本配置
@Bean
public ZookeeperConfigProfile zookeeperConfigProfile() {
ZookeeperConfigProfile configProfile = new ZookeeperConfigProfile(
Objects.requireNonNull(this.env.getProperty("configs.address")),
Objects.requireNonNull(this.env.getProperty("configs.env")),
this.env.getProperty("configs.version"));
return configProfile;
}
//得到具体组里的配置
@Bean({"groupPropDefault"})
public GeneralConfigGroup generalConfigGroupDefault() {
ZookeeperConfigProfile configProfile = this.zookeeperConfigProfile();
GeneralConfigGroup group = new ZookeeperConfigGroup(configProfile, this.env.getProperty("configs.groupdefault"));
return group;
}
/**
* 获取配置组
* @return
*/
public GeneralConfigGroup getConfigGroup(String group) {
return GROUPMAP.get(group);
}
/**
*
* 项目启动时会调用这个方法,把zk里的配置组存在临时变量GROUPMAP里,以后会用到
* 所以 数据源初始化,就设置在这个方法里
* @param environment
*/
@Override
public void setEnvironment(Environment environment) {
this.env = environment;
ZookeeperConfigProfile configProfile = this.zookeeperConfigProfile();
GROUPMAP.put("groupdefault", new ZookeeperConfigGroup(configProfile, this.env.getProperty("configs.groupdefault")));
}}
5.获得所有配置项后,就是让springboot去建立kafka链接了,这里相当于要重新实现KafkaAutoConfiguration的配置。建立一个KafkaConfig配置类,这里主要是配置所有kafka需要的bean:
@Configuration
@ConditionalOnClass({KafkaTemplate.class})
@EnableKafka
public class KafkaConfig {
// 把刚刚加载zk配置的类注入进来
@Autowired
private ZKConfiguration zkConfiguration;
// 创建 消费者工厂
@Bean("consumerFactory")
@ConditionalOnMissingBean({ConsumerFactory.class})
public ConsumerFactory<String, String> consumerFactory() {
// 创建工厂需要三个参数:
// 1. 消费者配置的map
// 2. key的反序列化实现类
// 3. value的反序列化实现类
return new DefaultKafkaConsumerFactory<String, String>(makeKafkaConfig(), new StringDeserializer(), new StringDeserializer());
}
// 创建生产者工厂
@Bean("producerFactory")
@ConditionalOnMissingBean({ProducerFactory.class})
public ProducerFactory<String, String> kafkaProducerFactory() {
// 生产者工厂的参数如消费者工厂
return new DefaultKafkaProducerFactory(makeKafkaConfig(), new StringSerializer(), new StringSerializer());
}
// 创建 kafkaTemplate 这个bean,有了这个bean才能在实际业务中使用kafka
@Bean("kafkaTemplate")
@ConditionalOnMissingBean({com.seckill.boot.common.util.KafkaTemplate.class})
public KafkaTemplate<String, Protobufable> kafkaTemplate(@Qualifier("producerFactory") ProducerFactory<String, String> kafkaProducerFactory,
@Qualifier("producerListener") ProducerListener<String, Protobufable> producerListener) {
KafkaTemplate<String, Protobufable> kafkaTemplate = new KafkaTemplate(kafkaProducerFactory);
kafkaTemplate.setProducerListener(producerListener);
kafkaTemplate.setDefaultTopic("groupdefault");
return kafkaTemplate;
}
@Bean("producerListener")
@ConditionalOnMissingBean({ProducerListener.class})
public ProducerListener<String, Protobufable> kafkaProducerListener() {
return new LoggingProducerListener();
}
@Bean
@ConditionalOnProperty(
name = {"spring.kafka.producer.transaction-id-prefix"}
)
@ConditionalOnMissingBean
public KafkaTransactionManager<?, ?> kafkaTransactionManager(ProducerFactory<?, ?> producerFactory) {
return new KafkaTransactionManager(producerFactory);
}
// zk里拿到的配置取出来
private Map<String, Object> makeKafkaConfig() {
// 获得配置的group
GeneralConfigGroup configGroup = zkConfiguration.getConfigGroup("groupdefault");
Map<String, Object> kafkaConfig = new HashMap<>();
kafkaConfig.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, configGroup.get("spring.kafka.bootstrap-servers"));
kafkaConfig.put(ConsumerConfig.GROUP_ID_CONFIG, configGroup.get("spring.kafka.consumer.group-id"));
kafkaConfig.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, configGroup.get("spring.kafka.consumer.auto-offset-reset"));
kafkaConfig.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, configGroup.get("spring.kafka.consumer.enable-auto-commit"));
kafkaConfig.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, configGroup.get("spring.kafka.consumer.auto-commit-interval"));
kafkaConfig.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, configGroup.get("spring.kafka.consumer.key-serializer"));
kafkaConfig.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, configGroup.get("spring.kafka.consumer.value-serializer"));
kafkaConfig.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, configGroup.get("spring.kafka.consumer.max-poll-records"));
kafkaConfig.put(ConsumerConfig.MAX_POLL_INTERVAL_MS_CONFIG, configGroup.get("spring.kafka.consumer.max-poll-interval-ms"));
kafkaConfig.put("ack-mode", configGroup.get("spring.kafka.listener.ack-mode"));
kafkaConfig.put("concurrency", configGroup.get("spring.kafka.listener.concurrency"));
kafkaConfig.put(ProducerConfig.ACKS_CONFIG, configGroup.get("spring.kafka.producer.acks"));
kafkaConfig.put(ProducerConfig.BATCH_SIZE_CONFIG, configGroup.get("spring.kafka.producer.batch-size"));
kafkaConfig.put(ProducerConfig.BUFFER_MEMORY_CONFIG, configGroup.get("spring.kafka.producer.buffer-memory"));
kafkaConfig.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, configGroup.get("spring.kafka.producer.key-serializer"));
kafkaConfig.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, configGroup.get("spring.kafka.producer.value-serializer"));
kafkaConfig.put(ProducerConfig.RETRIES_CONFIG, configGroup.get("spring.kafka.producer.retries"));
return kafkaConfig;
}
}
- 将kafka需要的bean配置好后,就能在实际业务中使用KafkaTemplate操作消息了
@Component
public class MqProviderImpl{
@Autowired
private KafkaTemplate<String, String> kafkaTemplate;
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