1、Spring Cloud Eureka

Eureka Client：服务注册
Eureka Server：服务发现
2、Eureka Server
A.Eureka Server依赖
```
<dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
```
B.在启动类添加Eureka Server服务端注解
```java package com.fcant.springcloudeurekasever;

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

/**

SpringCloudEurekaSeverApplication
启用EurekaServer服务端注解 *
encoding:UTF-8
@author Fcant 22:42 2019/12/8 */ @EnableEurekaServer @SpringBootApplication public class SpringCloudEurekaSeverApplication {

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

}

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## C.在配置文件配置服务端端口和Eureka服务相关配置
```yaml
server:
  port: 8000
spring:
  application:
    name: eureka-server
eureka:
  client:
    # 此应用为注册中心，false：不向注册中心注册自己
    register-with-eureka: false
    # 注册中心职责是维护服务实例，false：不检索服务
    fetch-registry: false
    service-url:
      defaultZone: http://127.0.0.1:8000/eureka

如果不配置eureka.client则会出现如下报错语雀内容

D.输入服务端访问的URL可以查看提供的Web管理的内容

3、GateWay Eureka Client

A.Eureka Client相关依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

B.在客户端启动类添加Eureka Client注解

I.直接在原有注解上添加`@EnableEurekaClient`注解

package com.fcant.springcloudgateway;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
/**
 * SpringCloudGateWayApplication
 *
 * encoding:UTF-8
 * @author Fcant 21:50 2019/12/8
 */
@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class SpringCloudGateWayApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringCloudGateWayApplication.class, args);
    }
}

II.使用`@SpringCloudApplication`注解替代`@EnableEurekaClient`和`@SpringBootApplication`注解

package com.fcant.springcloudgateway;
import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
/**
 * SpringCloudGateWayApplication
 *
 * encoding:UTF-8
 * @author Fcant 21:50 2019/12/8
 */
@EnableZuulProxy
@SpringCloudApplication
public class SpringCloudGateWayApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringCloudGateWayApplication.class, args);
    }
}

C.在配置文件配置客户端内容-application.yml

zuul:
  routes:
    fcant:
      path: /fcant-filter
spring:
  application:
    name: gateway-service
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:8000/eureka

D.启动客户端、刷新Server端程序

4、Consul&Eureka对比

Consul ：保证强一致性
- 服务注册相比Eureka会稍慢一些，Consul要求过半的节点都写入成功。
- Leader 挂掉时，重新选举期整个Consul不可用。
Eureka ：保证高可用
- 服务注册快，不需要等待注册信息复制到其他节点，也不保证复制成功。
- 当注册信息不相同时，每个Eureka节点依然能够正常对外提供服务。