springboot整合kafka實現發佈訂閱，kafka學習五

1.引入依賴

     <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
     </dependency>
     <dependency>
         <groupId>org.springframework.kafka</groupId>
         <artifactId>spring-kafka</artifactId>
     </dependency>
     <dependency>
         <groupId>org.projectlombok</groupId>
         <artifactId>lombok</artifactId>
         <optional>true</optional>
     </dependency>

2.yml配置

spring:
  kafka:              # 指定kafka 代理地址，可以多個
    bootstrap-servers: 192.168.211.137:9092,192.168.211.139:9092,192.168.211.140:9092
    template:    # 指定默認topic id
      default-topic: producer
    listener:   # 指定listener 容器中的線程數，用於提高併發量
      concurrency: 5
    consumer:
      group-id: myGroup # 指定默認消費者group id
      client-id: 200
      max-poll-records: 200
      auto-offset-reset: earliest # 最早未被消費的offset
    producer:
      batch-size: 1000 # 每次批量發送消息的數量
      retries: 3
      client-id: 200

3.代碼示例

1. 生產者

package com.wyu.tt06kafkademo.demo;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;

import java.util.Date;

@Slf4j
@Component
public class KafkaProducer {

    @Autowired
    private KafkaTemplate<String, String> kafkaTemplate;

    @Autowired
    private ObjectMapper objectMapper;

    public void send(String topic, Object body) {
        Message<String> message = new Message<>();
        message.setId(System.currentTimeMillis());
        message.setMessage(body.toString());
        message.setTime(new Date());
        String content = null;
        try {
            content = objectMapper.writeValueAsString(message);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        kafkaTemplate.send(topic, content);
        log.info("send {} to {} success!", message, topic);
        System.out.println("send "+ message +" to "+ topic +" success!");
    }
}

2. 消費者

package com.wyu.tt06kafkademo.demo;

import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.Optional;

@Slf4j
@Component
public class KafkaConsumer {

    /**
     * 有消息就讀取,讀取消息topic，offset，key，value等信息
     */
    @KafkaListener(topics = {"kafka1"})
    public void listen(ConsumerRecord<?, ?> record) {
        Optional<?> kafkaMessage = Optional.ofNullable(record.value());
        if (kafkaMessage.isPresent()) {
            Object message = kafkaMessage.get();
            log.info("詳細消息讀取-------------------->");
            log.info("message:{} + record:{}", message, record);
        }
    }

    /**
     * 有消息就讀取,批量讀取消息
     */
    @KafkaListener(topics = "kafka1")
    public void onMessage(List<String> crs) {
        for(String str : crs){
            log.info("批量讀取-------------------->");
            log.info("kafka1:" + str);
        }
    }

    /**
     * 有消息就讀取message
     */
    @KafkaListener(topics = {"kafka1"})
    public void receiveMessage(String message){
        log.info("讀取message-------------------->");
        log.info("kafka1:" + message);
    }
}

3. controller

package com.wyu.tt06kafkademo.controller;

import com.wyu.tt06kafkademo.demo.KafkaProducer;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@Slf4j
@RestController
public class KafkaController {
    @Autowired
    private KafkaProducer kafkaProducer;

    @GetMapping("/kafka/{topic}")
    public String send(@PathVariable("topic") String topic, @RequestParam String message) {
        kafkaProducer.send(topic, message);
        return "success";
    }
}