Eureka介绍

在这里插入图片描述

三大角色

Eureka Serrver:提供服务的注册与发现。zookeeper
Service Provider:将自身服务注册到 Eureka中，从而使消费方能够找到
Service Consumer:服务消费方从Eureka中获取注册服务列表，从而找到消费服务

Eureka详解

Eureka注册中心创建(springcloud-eureka模块)

pom.xml

<?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/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-pom</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
        <relativePath>../springcloud-pom/pom.xml</relativePath>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-eureka</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>
</project>

application.yml

server:
  port: 8761
#Eureka配置
eureka:
  instance:
    hostname: localhost #Eureka服务端的实例名称
  client:
    register-with-eureka: false #表示是否向Eureka注册中心注册自己
    fetch-registry: false #要不要去注册中心获取其他服务的地址
    service-url: #监控页面
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

启动类

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

大坑
Dependencies的sdk版本如果选择过高，springboot将无法启动

启动之后访问：http://localhost:8761/

服务注册-信息配置-自我保护机制(服务提供模块)

服务提供者注册到Eureka注册中心

加依赖

<!--完善监控信息-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>

Eureka配置

#Eureka配置，服务注册到哪里
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/
  instance:
    instance-id: springcloud-server-provider #修改Eureka的默认描述信息

#info配置
info:
  app.name: zzq-springcloud
  company.name: blog.com

启动类加注解：@EnableEurekaClient

@EnableEurekaClient
@SpringBootApplication //在服务启动后自动注册到eureka
public class ServerProviderApplicaiton {
    public static void main(String[] args) {
        SpringApplication.run(ServerProviderApplicaiton.class,args);
    }
}

CAP原则

C:一致性
A:可用性
P:容错性
在这里插入图片描述

Ribbon：负载均衡及Ribbon

Ribbon是基于Netflix Ribbon实现的一套客户端负载均衡的工具

Ribbon能干嘛

服务消费方(客户端)集成Ribbon

pom.xml

 <!--ribbon负载均衡-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>
        <!--Eureka-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.4.6.RELEASE</version>
        </dependency>

application.yml

#Eureka配置
eureka:
  client:
    register-with-eureka: false #不向Eureka注册自己
    service-url:
      defaultZone: http://localhost:8761/eureka/ #客户端注册进Eureka

configBean

@Configuration
public class ConfigBean {
    //配置负载均衡实现RestTemplate
    @Bean
    @LoadBalanced //Ribbon配置
    public RestTemplate geteRestTemplate(){
        return new RestTemplate();
    }
}

controller
//Ribbon,我们这里的地址，应该是一个变量，通过服务名来访问 private static final String RESET_URL_PREFIX="http://SPRINGCLOUD-PROVIDER-DEPT";

@RestController
public class DeptConsumerController {
    //理解：消费者，不应该有service层
    @Autowired
    private RestTemplate restTemplate; //提供多种便捷访问远程http服务的方法，简单的restFul服务模板

    //Ribbon,我们这里的地址，应该是一个变量，通过服务名来访问
    private static final String RESET_URL_PREFIX="http://SPRINGCLOUD-PROVIDER-DEPT";

    @GetMapping("/consumer/dept/{deptNo}")
    public Dept get(@PathVariable("deptNo") Long deptNo){
        return restTemplate.getForObject(RESET_URL_PREFIX+"/dept/"+deptNo,Dept.class);
    }

    @GetMapping("/consumer/list")
    public List<Dept> queryAll(){
        return restTemplate.getForObject(RESET_URL_PREFIX+"/dept/queryAll",List.class);
    }

    @PostMapping("/consumer/dept/add")
    public boolean add(@RequestBody Dept dept){
        return restTemplate.postForObject(RESET_URL_PREFIX+"/dept/add",dept,Boolean.class);
    }
}