springcloud搭建kafka

环境：zk+springcloud+eureka+kafka
系统：windows

springcloud版本：Hoxton 2.3.1
适配版本
springboot版本：2.2.5

各版本对应关系
Release Train/Boot Version
Hoxton /2.2.x
Greenwich /2.1.x
Finchley /2.0.x
Edgware /1.5.x
Dalston /1.5.x

搭建中遇到的问题
1.kafka启动报错如下：
java.io.IOException: Map failed
java.lang.OutOfMemoryError: Map failed
解决：从字面上看是内存不够，尝试更改jvm内存，结果失败。
分析错误日志hs_err_pid10384.log，里面有提到：在64位操作系统上使用64位Java，重新安装64位java解决问题！


日志最下方有当前java的信息

2.Group coordinator promote.localdomain:9092 (id: 2147483647 rack: null) is unavailable or invalid, will attempt rediscovery
解决：消费者没连接上服务，原因是搭建失败。通过分析错误日志hs_err_pid10384.log发现，需要使用64位的java,。详细解决步骤同问题1

步骤：
1.先启动zk,双击zkServer.cmd

2.启动kafka，bin同级目录命令框中执行一下命令

.inwindowskafka-server-start.bat .configserver.properties

3.搭建springcloud项目
eureka用作Service发现服务
zk用作分布式协同服务，配合kafka使用
txlcn-tm是分布式事务（待完善，不影响整体）

eureka-service

导包：

        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-server
        

配置

server:
  port: 8091
eureka:
  instance:
    hostname: localhost #服务注册中心实例的主机名
  server:
    enableSelfPreservation: true #服务端开启自我保护模式。无论什么情况，服务端都会保持一定数量的服务。避免client与server的网络问题，而出现大量的服务被清除。
    renewalPercentThreshold: 0.1 #在设置的时间范围类，期望与client续约的百分比。
  client:
    register-with-eureka: false #实例是否在eureka服务器上注册自己的信息以供其他服务发现，默认为true
    fetch-registry: false #此客户端是否获取eureka服务器注册表上的注册信息，默认为true
service-url: 
  defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #服务地址

启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaServerApplication.class, args);
    }

}

eureka-provider

导包

        
            org.springframework.cloud
            spring-cloud-netflix-eureka-server
        
        
            org.springframework.cloud
            spring-cloud-stream
            compile
        
        
            org.springframework.cloud
            spring-cloud-stream-binder-kafka
        

配置

server:
  port: 8081
spring:
  cloud:
    stream:
      kafka:
        binder:
          brokers: localhost:9092         #Kafka的消息中间件服务器
          zk-nodes: localhost:2181        #Zookeeper的节点，如果集群，后面加,号分隔
          auto-create-topics: true        #如果设置为false,就不会自动创建Topic 有可能你Topic还没创建就直接调用了。
      bindings:
        output:      #这里用stream给我们提供的默认output，后面会讲到自定义output
          destination: stream-demo    #消息发往的目的地
          content-type: text/plain    #消息发送的格式，接收端不用指定格式，但是发送端要
eureka:
  instance:
    appname: eureka-provider
  client:
    service-url:
      defaultZone: http://localhost:8091/eureka/

eureka的服务提供方

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

//rest 风格控制器
@RestController
public class EurekaProviderController {
    @RequestMapping("/getInfo")
    public String getDemoInfo() {
        return "this is a provider service";
    }

    @RequestMapping("/getString")
    public String getDemoInfo1(String userId) {
        return userId + ",this is a provider service";
    }

}

kafka消息发送端

import com.eureka.provider.service.KafkaSendService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class KafkaProviderController {

    @Autowired
    private KafkaSendService kafkaSendService;

    @RequestMapping("/send/{msg}")
    public void send(@PathVariable("msg") String msg) {
        System.out.println("发送消息------->>"+msg);
        kafkaSendService.sendMsg(msg);
    }
}

kafka服务接口

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.messaging.Source;
import org.springframework.integration.support.MessageBuilder;

//这个注解给我们绑定消息通道的，Source是Stream给我们提供的，可以点进去看源码，可以看到output和input,这和配置文件中的output，input对应的。
@EnableBinding(Source.class)
public class KafkaSendService {

    @Autowired
    private Source source;

    public void sendMsg(String msg) {
        source.output().send(MessageBuilder.withPayload(msg).build());
    }
}

启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaProviderApplication.class, args);
    }

}

eureka-customer

导包

        
            org.springframework.cloud
            spring-cloud-netflix-eureka-server
        
        
            org.springframework.cloud
            spring-cloud-stream
            compile
        
        
            org.springframework.cloud
            spring-cloud-stream-binder-kafka
        

配置

server:
  port: 8082
spring:
  cloud:
    stream:
      kafka:
        binder:
          brokers: localhost:9092         #Kafka的消息中间件服务器
          zk-nodes: localhost:2181        #Zookeeper的节点，如果集群，后面加,号分隔
          auto-create-topics: true        #如果设置为false,就不会自动创建Topic 有可能你Topic还没创建就直接调用了。
      bindings:
        input: #input是接收，注意这里不能再像前面一样写output了
          destination: stream-demo #消息接收的目的地
eureka:
  instance:
    appname: eureka-customer
  client:
    service-url:
      defaultZone: http://localhost:8091/eureka/

eureka服务消费方

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpMethod;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class EurekaCustomerController {

    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping("/test1")
    public String getEurekaServiceInfo() {
        /**
         * exchange(url,type,paras,resutType)
         * url：请求地址
         * type：请求类型 get,post
         * paras：参数
         * resutType：返回值类型
         */
        String url = "http://localhost:8081/getInfo";
        HttpMethod type = HttpMethod.GET;
        RequestEntity paras = null;
        ResponseEntity responseEntity = restTemplate.exchange(url, type, paras, String.class);
        return responseEntity.getBody();
    }

    @RequestMapping("/test2")
    public String getString1() {
        //getForObject 调用无参方法，返回结果为String的方法
        String url = "http://localhost:8081/getInfo";
        String res = restTemplate.getForObject(url, String.class);
        return res;
    }

    @RequestMapping("/test3")
    public String getString2() {
        //getForObject 调用有参方法，路径添加参数。返回结果为String的方法
        String url = "http://localhost:8081/getString?userId=sn001";
        String res = restTemplate.getForObject(url, String.class);
        return res;
    }

}

kafka消息接收端

import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.annotation.StreamListener;
import org.springframework.cloud.stream.messaging.Sink;
import org.springframework.kafka.support.Acknowledgment;
import org.springframework.kafka.support.KafkaHeaders;
import org.springframework.messaging.Message;

//消息接收端，stream给我们提供了Sink,Sink源码里面是绑定input的，要跟我们配置文件的input关联的。
@EnableBinding(Sink.class)
public class KafkaRecieveService {

    @StreamListener(Sink.INPUT)
    public void process(Message message) {
        System.out.println("接收到消息----------->>>"+message.getPayload());
        Acknowledgment acknowledgment = message.getHeaders().get(KafkaHeaders.ACKNOWLEDGMENT, Acknowledgment.class);
        if (acknowledgment != null) {
            System.out.println("Acknowledgment provided");
            acknowledgment.acknowledge();
        }
    }
}

启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaServer
public class EurekaCustomerApplication {

    public static void main(String[] args) {
        SpringApplication.run(EurekaCustomerApplication.class, args);
    }

    //向spring里注入一个RestTemplate对象
    @Bean
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}