6.eureka服务发现实例（springcloud）

1.首先启动一个eureka-server

本次测试为了方便选择使用单机配置

application.yml

#单机
server:
  port: 8761 #eureka��Ĭ�϶˿�
spring:
  application:
    name: eureka-server #Ӧ������
#eureka的配置分为3类，server  client 实例的  eureka-server既是服务端又是客户端
eureka:
  server:
    eviction-interval-timer-in-ms: 1000 #服务端间隔多少毫秒做定期删除的操作
    renewal-percent-threshold: 0.85 #续约百分比，超过85%的应用没有和你续约，那么eureka会保护服务，不会提出任何一个
  instance: #实例的配置
    instance-id: ${eureka.instance.hostname}:${spring.application.name}:${server.port} #主机名称：应用名称：端口号
    hostname: localhost #主机名称或则服务的ip
    prefer-ip-address: true #以ip的形式显示具体的服务信息
    lease-renewal-interval-in-seconds: 5 #服务实例的续约时间间隔
 
#集群
#server:
#  port: 8761
#spring:
#  application:
#    name: eureka-server
#eureka:
#  client:
#    service-url:
#      defaultZone: http://peer2:8762/eureka,http://peer3:8763/eureka
#  instance:
#    instance-id: ${eureka.instance.hostname}:${spring.application.name}:${server.port}
#    hostname: peer1
#    prefer-ip-address: true
#    lease-renewal-interval-in-seconds: 5
 
#集群的终极方案
#server:
#  port: 8761
#spring:
#  application:
#    name: eureka-server
#eureka:
#  client:
#    service-url:
#      defaultZone: http://peer1:8761/eureka,http://peer2:8762/eureka,http://peer3:8763/eureka
#  instance:
#    instance-id: ${spring.application.name}:${server.port}
#    prefer-ip-address: true
#    lease-renewal-interval-in-seconds: 5
 

2.编写eureka-client-b的配置

application.yml
 

server:
  port: 8081
spring:
  application:
    name: eureka-client-b
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka
  instance:
    prefer-ip-address: true
    instance-id: ${eureka.instance.hostname}:${spring.application.name}:${server.port}
    hostname: localhost
    lease-renewal-interval-in-seconds: 10

3.编写eureka-client-a的配置文件

#单机
server:
  port: 8080 #�ͻ��˵Ķ˿�û��Ҫ��
spring:
  application:
    name: eureka-client-a
#ע��
eureka:
  client:
    service-url: #ע���ַ
      defaultZone: http://localhost:8761/eureka
    register-with-eureka: true #可以不往eureka-server注册
    fetch-registry: true #应用是否去拉取服务列表到本地
    registry-fetch-interval-seconds: 10 #为了缓解服务列表的脏读问题
  instance:
    hostname: localhost #应用的主机名称 最好写主机ip
    instance-id: ${eureka.instance.hostname}:${spring.application.name}:${server.port}
    prefer-ip-address: true #显示ip
    lease-renewal-interval-in-seconds: 10 #实例续约的时间
 
 
#集群
#server:
#  port: 8080 #�ͻ��˵Ķ˿�û��Ҫ��
#spring:
#  application:
#    name: eureka-client-a
##ע��
#eureka:
#  client:
#    service-url: #ע���ַ
#      defaultZone: http://peer1:8761/eureka
#    register-with-eureka: true #可以不往eureka-server注册
#    fetch-registry: true #应用是否去拉取服务列表到本地
#    registry-fetch-interval-seconds: 10 #为了缓解服务列表的脏读问题
#  instance:
#    hostname: localhost #应用的主机名称 最好写主机ip
#    instance-id: ${eureka.instance.hostname}:${spring.application.name}:${server.port}
#    prefer-ip-address: true #显示ip
#    lease-renewal-interval-in-seconds: 10 #实例续约的时间
 
 
 

4.在eureka-client-a的model里面创建DiscoveryController

里面编写方法，通过服务eureka-client-b的应用名，找到服务eureka-client-b的具体信息。

package com.it.controller;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
 
import java.util.List;
 
@RestController
public class DiscoveryController {
 
    @Autowired
    private DiscoveryClient discoveryClient;
 
    @GetMapping("test")
    public String doDiscovery(String serviceName){
        // 这就是服务发现，通过服务的应用名，找到服务的具体信息
        List instances = discoveryClient.getInstances(serviceName);
        //
        instances.forEach(System.out::println);
        //这里去找b的ip和port
        return instances.get(0).toString();
 
    }
 
}

5.先运行eureka-server，再运行eureka-client-b,最后运行eureka-client-a

进入localhost:8761进行查看，发现应用实例都已经注册了

 通过eureka-client-a中编写的方法，用eureka-client-b作为参数进行查询eureka-client-b的具体信息，并遍历打印出来。

http://localhost:8080/test?serviceName=eureka-client-b