SpringCloud服务注册与发现

Spring Cloud服务注册与发现

Spring Cloud集成了搭建分布式服务一系列框架,如服务注册与发现Eureka,熔断器Hystrix,路由网关Zuul,链路追踪zipkin,今天主要讲解Eureka的使用。

Eureka是什么?

Eureka是Netflix开源的一款提供服务注册和发现的产品,它提供了完整的Service Registry和Service Discovery实现。也是springcloud体系中最重要最核心的组件之一,我们通过下面这样图就可以了解

48EB8D2E311BF36563200EF5B0015EB6

1)服务提供方向Eureka注册自己的服务,

2)消费者向Eureka获取自己需要的服务,和提供方建立连接

3) 如果服务方出现故障,Eureka会自动将服务方从注册列表中删除

搭建项目

创建Eureka服务

首先创建一个Maven项目,指定spring boot,spring cloud 版本

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.1.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>
    <spring-cloud.version>Finchley.SR2</spring-cloud.version>
</properties>

创建一个模块,我们称为EurekaServer,使用Eureka只需要引入maven包,然后启动项目就可以了,很方面,如下:

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

配置application.yml文件

server:
  port: 8081

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

spring:
  application:
    name: eurka-server

添加注解@EnableEurekaServer,并启动EurekaServer

@SpringBootApplication
@EnableEurekaServer
public class EurakaServerApplication {

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

启动EurekaServer,地址为:http://localhost:8081/eureka

创建提供方服务

添加maven依赖

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

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>

创建服务接口

@RestController
public class AirportController {

    @Autowired
    private AirportService airportService;

    @RequestMapping("/getAirport")
    public AirportBean getAirport(@RequestParam("threeCode") String threeCode) {
        return airportService.getAirport(threeCode);
    }

}

@Service
public class AirportService {

    @Value("${server.port}")
    private int port;

    public AirportBean getAirport(String threeCode) {
        AirportBean bean = new AirportBean();
        bean.setName("北京首都国际机场");
        bean.setThreeCode(threeCode);
        bean.setPort(port);
        return bean;
    }

}

public class AirportBean {

    private String threeCode;
    private String name;
    private int port;
}

修改application.yml文件

<code>server:
  port: 8082

spring:
  application:
    name: dynamic-service

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8081/eureka/</code>

添加@EnableEurekaClient注解,这里我们为了方便演示负载均衡,同时也启动了两个实例,端口分别为8082,8083

@SpringBootApplication
@EnableEurekaClient
public class DynamicServiceApplication {

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

创建服务消费方

我们再项目下再新建一个模块,称为springcloudclient,添加maven依赖

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

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

这里我们使用了feign的服务调用方式,Spring cloud有两种服务调用方式,一种是ribbon+restTemplate,另一种是feign,ribbon类似一种rest风格的API调用方式,而feign整合了ribbon,具有负载均衡的能力,通过注解的方式,使代码看起来更加简洁,另外feign整合了Hystrix,具有熔断的能力

调用服务方的接口

@RestController
public class AirportFeignController {

    @Autowired
    private AirportFeignService airportFeignService;

    @RequestMapping(value = "/getAirport",method = RequestMethod.GET)
    public AirportBean getAirport(@RequestParam("threeCode") String threeCode) {
        return airportFeignService.getAirport(threeCode);
    }

}

@FeignClient(value = "dynamic-service", fallback = AirportFeignFallbackService.class)
public interface AirportFeignService {

    @RequestMapping(value = "/getAirport",method = RequestMethod.GET)
    public AirportBean getAirport(@RequestParam("threeCode") String threeCode);

}

// 服务失败后熔断,调用的方法
public class AirportFeignFallbackService implements AirportFeignService {
    @Override
    public AirportBean getAirport(String threeCode) {
        return null;
    }
}

public class AirportBean {
    private String threeCode;
    private String name;
    private int port;
}

配置application.yml文件

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
server:
  port: 8084
spring:
  application:
    name: service-feign

添加@ EnableEurekaClient,@EnableDiscoveryClient, @EnableFeignClients注解,端口为8084,

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableFeignClients
public class SpringCloudServerApplication {

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

好了下面可以演示springcloud的服务注册与发现了,通过上面的例子,我们启动了Eureka服务,分别为:8081,同时启动了两个服务提供方,注册到Eureka中,端口分别为8082和8083,接着我们启动了一个服务消费方,端口为8084,我们分别启动他们
打开Eureka的服务页面:http://localhost:8081

55AD7F4965A098E135257B0B04BBF3B6

可以发现有两个服务方已经注册上了,我们调用消费方的接口,发现消费方会使用负载均衡的方式分别访问服务方

 

有道词典

org.springframe …

详细X

  org.springframework.boot   spring-boot-starter-parent   2.1.1.RELEASE      utf – 8   utf – 8   1.8   Finchley.SR2

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