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Java操作Kafka执行不成功的解决方法，Kafka Broker Advertised.Listeners属性的设置

Posted on 2018-04-21 16:43  刚泡  阅读(24273)  评论(1)  编辑  收藏  举报
创建Spring Boot项目继承Kafka，向Kafka发送消息始终不成功。具体项目配置如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.lodestone</groupId>
    <artifactId>lodestone-kafka</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>lodestone-kafka</name>
    <description>Lodestone kafka</description>
    <parent>
         <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
         <version>1.5.12.RELEASE</version>
         <relativePath />
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <java.version>1.8</java.version>
    </properties>
    <dependencies>
         <dependency>
            <groupId>org.springframework.kafka</groupId>
           <artifactId>spring-kafka</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
         </dependency>
         
         <!--  https://mvnrepository.com/artifact/com.alibaba/fastjson -->
         <dependency>
             <groupId>com.alibaba</groupId>
             <artifactId>fastjson</artifactId>
             <version>1.2.47</version>
         </dependency>
         <!--  https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
         </dependency>
         <!--  https://mvnrepository.com/artifact/org.slf4j/log4j-over-slf4j -->
         <dependency>
             <groupId>org.slf4j</groupId>
              <artifactId>log4j-over-slf4j</artifactId>
         </dependency>
         
    </dependencies>
    <build>
         <plugins>
             <plugin>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-maven-plugin</artifactId>
             </plugin>
         </plugins>
    </build>
</project>
 
 
application.yml配置：
spring:
  kafka:
    bootstrap-servers:
      - 192.168.52.131:9092
    consumer:
      auto-offset-reset: earliest
      group-id: console-consumer-53989
      key-deserializer:org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer:org.apache.kafka.common.serialization.StringDeserializer
    producer:
      key-serializer:org.apache.kafka.common.serialization.StringSerializer
      value-serializer:org.apache.kafka.common.serialization.StringSerializer
logging:
  level:
    root: DEBUG
    org:
      springframework: DEBUG
      mybatis: DEBUG
 
 
生产者代码：
package com.lodestone.kafka.producer;
 
import java.util.Date;
import java.util.UUID;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
 
import com.alibaba.fastjson.JSON;
import com.lodestone.kafka.message.LodestoneMessage;
 
@Component
public class Sender {
    
    @Autowired
    private KafkaTemplate kafkaTemplate;
 
    public void sendMessage() {
        
        LodestoneMessage message = new LodestoneMessage();
        message.setId(UUID.randomUUID().toString().replaceAll("-", ""));
        message.setMsg(UUID.randomUUID().toString());
        message.setSendTime(new Date());
        kafkaTemplate.send("test", JSON.toJSONString(message));
    }
}
 
 
 
消息代码定义：
package com.lodestone.kafka.message;
 
import java.io.Serializable;
import java.util.Date;
 
public class LodestoneMessage implements Serializable {
 
    private static final long serialVersionUID = -6847574917429814430L;
 
    private String id;
    private String msg;
    private Date sendTime;
 
    public String getId() {
        return id;
    }
 
    public void setId(String id) {
        this.id = id;
    }
 
    public String getMsg() {
        return msg;
    }
 
    public void setMsg(String msg) {
        this.msg = msg;
    }
 
    public Date getSendTime() {
        return sendTime;
    }
 
    public void setSendTime(Date sendTime) {
        this.sendTime = sendTime;
    }
 
}
 
 
 
Spring Boot应用启动类：
package com.lodestone.kafka;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
 
import com.lodestone.kafka.producer.Sender;
 
@SpringBootApplication
public class LodestoneKafkaApplication {    
 
    public static void main(String[] args) throws InterruptedException {
        
        ApplicationContext app = SpringApplication.run(LodestoneKafkaApplication.class, args);
        //测试
        for(int i=0; i<5; i++) {
            Sender sender = app.getBean(Sender.class);
            sender.sendMessage();
            Thread.sleep(500);
        }
    }
}
 
 
 
将应用的日志调整位Debug级别，启动应用时看到如下报错：
2018-04-21 16:05:10.755 DEBUG 10272 --- [ad | producer-1] o.apache.kafka.common.network.Selector   : Connection with localhost/127.0.0.1 disconnected
 
java.net.ConnectException: Connection refused: no further information
    at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[na:1.8.0_111]
    at sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source) ~[na:1.8.0_111]
    at org.apache.kafka.common.network.Selector.poll(Selector.java:291) [kafka-clients-0.10.1.1.jar:na]
    at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:260) [kafka-clients-0.10.1.1.jar:na]
    at org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:236) [kafka-clients-0.10.1.1.jar:na]
    at org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:148) [kafka-clients-0.10.1.1.jar:na]
    at java.lang.Thread.run(Unknown Source) [na:1.8.0_111]
 
 
可以看到报错第一句显示：Connection with localhost/127.0.0.1 disconnected
但是我明明在application.yml中配置了我的Kafka Server的地址是：192.168.52.131:9092，而在实际连接kafka服务器时却使用的localhost/127.0.0.1这个地址，所以导致无法连接kafka Server。
 
经过百度，得知，在设置Kafka的时候，需要设置advertised.listeners这个属性。
 
该属性在config/server.properties中的描述如下：
# Hostname and port the broker will advertise to producers and consumers. If not set,
# it uses the value for "listeners" if configured.  Otherwise, it will use the value
# advertised.listeners=PLAINTEXT://:your.host.name:9092
 
翻译过来就是hostname和端口是用来建议给生产者和消费者使用的，如果没有设置，将会使用listeners的配置，如果listeners也没有配置，将使用java.net.InetAddress.getCanonicalHostName()来获取这个hostname和port，对于ipv4，基本就是localhost了。
 
"PLAINTEXT"表示协议，可选的值有PLAINTEXT和SSL，hostname可以指定IP地址，也可以用"0.0.0.0"表示对所有的网络接口有效，如果hostname为空表示只对默认的网络接口有效
也就是说如果你没有配置advertised.listeners，就使用listeners的配置通告给消息的生产者和消费者，这个过程是在生产者和消费者获取源数据(metadata)。
 
因此重新设置advertised.listeners为如下：
advertised.listeners=PLAINTEXT://192.168.52.131:9092
 
 
需要注意的是，如果Kafka有多个节点，那么需要每个节点都按照这个节点的实际hostname和port情况进行设置。
 
每个节点都设置之后，再重新启动Spring Boot应用，则能够正常连接Kafka Server，并能够正常发送消息了。
 
 
 
部分援引和参考：