1、kafkaTemplate.send()方法

1.1、springboot集成kafka发送消息Message对象消息

生产者代码

package com.power.producer;import org.springframework.kafka.annotation.KafkaHandler;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;import javax.annotation.Resource;@Component
public class EventProducer {@Resourceprivate KafkaTemplate<String,String> kafkaTemplate;public void sendMessage(){//通过构建器模式创建Message对象Message message = MessageBuilder.withPayload("hello-message").setHeader(KafkaHeaders.TOPIC,"test-topic-02")//在header中放置topic的名字.build();kafkaTemplate.send(message);}
}

2、测试类

package com.power;import com.power.producer.EventProducer;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;@SpringBootTest
public class SpringBoot01KafkaBaseApplication {@Resourceprivate EventProducer eventProducer;@Testvoid testMessage(){eventProducer.sendMessage();}@Testvoid testMessage(){eventProducer.sendMessage();}
}

1.2、springboot集成kafka发送ProducerRecord对象消息

生产者

package com.power.producer;import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;@Component
public class EventProducer {@Resourceprivate KafkaTemplate<String,String> kafkaTemplate;public void sendMessage(){//通过构建器模式创建Message对象Message message = MessageBuilder.withPayload("hello-message").setHeader(KafkaHeaders.TOPIC,"test-topic-02")//在header中放置topic的名字.build();kafkaTemplate.send(message);}public void sendProducerRecord(){//Headers里面放一些信息（信息是key-value键值对），到时候消费组接收到消息后，可以拿到这个Headers里面放的信息Headers headers = new RecordHeaders();headers.add("phone","17676767676".getBytes(StandardCharsets.UTF_8));headers.add("orderId","OD1456467576467".getBytes(StandardCharsets.UTF_8));//String topic, Integer partition, Long timestamp, K key, V value, Iterable<Header> headersProducerRecord<String,String> record =new ProducerRecord("test-topic-02", 0, System.currentTimeMillis(), "key1", "value", headers);kafkaTemplate.send(record);}
}

测试类：

package com.power;import com.power.producer.EventProducer;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;@SpringBootTest
public class SpringBoot01KafkaBaseApplication {@Resourceprivate EventProducer eventProducer;@Testvoid testProducerRecord(){eventProducer.sendProducerRecord();}}

1.3、springboot集成kafka发送指定分区消息

生产者：（方法sendEvent4）

package com.power.producer;import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;@Component
public class EventProducer {@Resourceprivate KafkaTemplate<String,String> kafkaTemplate;public void sendEvent4(){//String topic, Integer partition, Long timestamp, K key, V datakafkaTemplate.send("test-topic-02",0,System.currentTimeMillis(),"k2","hello-kafka");}
}

测试类：

package com.power;import com.power.producer.EventProducer;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;@SpringBootTest
public class SpringBoot01KafkaBaseApplication {@Resourceprivate EventProducer eventProducer;@Testvoid sendEvent4(){eventProducer.sendEvent4();}
}

2、kafkaTemplate.sendDefault()方法

生产者：

package com.power.producer;import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;@Component
public class EventProducer {@Resourceprivate KafkaTemplate<String,String> kafkaTemplate;public void sendDefault(){//Integer partition, Long timestamp, K key, V datakafkaTemplate.sendDefault(0,System.currentTimeMillis(),"k3","hello-kafka");}
}

测试类：

package com.power;import com.power.producer.EventProducer;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;@SpringBootTest
public class SpringBoot01KafkaBaseApplication {@Resourceprivate EventProducer eventProducer;@Testvoid sendDefault(){eventProducer.sendDefault();}
}

配置文件：设置默认topic
不设置topic运行生产者会报找不到topic的错。

3、kafkaTemplate.send(…)和kafkaTemplate.sendDefault(…)的区别

4、发送对象消息

生产者：

package com.power.producer;import com.power.model.User;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.common.header.Headers;
import org.apache.kafka.common.header.internals.RecordHeaders;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.kafka.support.SendResult;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;
import org.springframework.util.concurrent.ListenableFuture;import javax.annotation.Resource;
import java.nio.charset.StandardCharsets;
import java.util.Date;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;@Component
public class EventProducer {@Resourceprivate KafkaTemplate<String,String> kafkaTemplate;@Resourceprivate KafkaTemplate<String,Object> kafkaTemplate2;public void getResult3(){User user = User.builder().id(1208).phone("16767667676").birthday(new Date()).build();//分区是null，让kafka自己去决定把消息发送到哪个分区kafkaTemplate2.sendDefault(null,System.currentTimeMillis(),"k3",user);}}

实体类：

package com.power.model;import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;import java.util.Date;@Builder
@AllArgsConstructor
@NoArgsConstructor
@Data
public class User {private Integer id;private String phone;private Date birthday;}

测试类：

package com.power;import com.power.producer.EventProducer;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import javax.annotation.Resource;@SpringBootTest
public class SpringBoot01KafkaBaseApplication {@Resourceprivate EventProducer eventProducer;@Testvoid getResult2(){eventProducer.getResult3();}
}

配置文件

spring:application:#应用名称name: spring-boot-01-kafka-base#kafka连接地址（ip+port）kafka:bootstrap-servers: <你的kafka服务器IP>:9092#配置生产者(有24个配置)producer:value-serializer: org.springframework.kafka.support.serializer.JsonSerializer#配置消费者(有24个配置)consumer:auto-offset-reset: earliesttemplate:default-topic: default-topic