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Today, the editor will share with you the relevant knowledge points about how to use Spring Cloud's Eureka to achieve service registration. The content is detailed and the logic is clear. I believe most people still know too much about this knowledge, so share this article for your reference. I hope you can get something after reading this article. Let's take a look.

Eureka is an open source service registration discovery component of Netflix. Service discovery can be said to be the core function of micro-service architecture. After micro-service deployment, there must be service registration and discovery capabilities, and Eureka plays this role. If you have ever used dubbo, you must know that the service registration and discovery functions in dubbo are implemented in zookeeper.

Eureka is currently in version 2.x, and it has been officially announced that updates will no longer be maintained. But in fact, Eureka is already very stable, and there is no problem as a registry. Spring Cloud integrates Eureka and makes a perfect package. It is convenient for us to use simple configuration when developing with Spring boot.

There are three types of roles in the micro-service framework, namely, registry, service provider, and service consumer. Registry is the protagonist Eureka today. This article briefly explains the use of Spring Cloud Eureka, simulates the implementation of a single point and highly available registry, and briefly introduces how service providers and service consumers use the service registration and discovery functions provided by Eureka.

Version description

Java: 1.8

Spring Boot: 2.1.3.RELEASE

Spring Cloud: Finchley.SR2

So let's talk about the version, because the package name of the Finchley.SR2 version has changed from the previous version, so you should be careful when referencing the maven package.

Single point registration center

Create an Eureka registry

1. Reference the maven package, where

Org.springframework.cloud

Spring-cloud-dependencies

Finchley.SR2

Pom

Import

Org.springframework.cloud

Spring-cloud-starter-netflix-eureka-server

Org.springframework.boot

Spring-boot-starter-actuator

2. Create a new bootstrap.yml and configure the Spring cloud parameter

Spring:

Application:

Name: kite-eureka-center

Cloud:

Inetutils: # # Network card settings

IgnoredInterfaces: # # ignored Nic

-docker0

-veth.*

-VM.*

PreferredNetworks: # # priority network segment

-192.168

3. Create a new application.yml and configure the parameters

Server:

Port: 3000

Eureka:

Instance:

Hostname: eureka-center

Appname: registry

Client:

RegisterWithEureka: false # when single point is set to false to disable self-registration

FetchRegistry: false

ServiceUrl:

DefaultZone: http://localhost:3000/eureka

Server:

EnableSelfPreservation: false

EvictionIntervalTimerInMs: 4000

The difference between bootstrap.yml and application.yml:

Bootstrap.yml starts before application.yml

Bootstrap.yml configures name, spring.cloud.config.server.git.uri, and some encryption/decryption (encryption / decryption) information of application

The information of application.yml will overwrite the contents of bootstrap.yml when the same configuration is encountered.

4. Create a new Application.java startup file

@ EnableEurekaServer

@ SpringBootApplication

Public class Application {

Public static void main (String [] args) {

SpringApplication.run (Application.class, args)

}

}

@ EnableEurekaServer means to use the EurekaServer side function, that is, to launch as a registry node.

5. Run Application.java and visit http://localhost:3000 to see the ui console provided by Eureka.

Create a service provider

Next, create a service provider and register with the Eureka registry created above.

1. Add maven dependency package

Org.springframework.boot

Spring-boot-starter-web

Org.springframework.cloud

Spring-cloud-starter-netflix-eureka-client

2. Configure application.yml

Server:

Port: 3001

Eureka:

Instance:

PreferIpAddress: true

Client:

ServiceUrl:

DefaultZone: http://localhost:3000/eureka # # sign in to eureka

Spring:

Application:

Name: single-provider # # application name, which will be used later in the consumer

3. Create a simple RESTful interface controller

@ Slf4j

@ RestController

Public class ProviderController {

@ Autowired

Private DiscoveryClient discoveryClient

@ RequestMapping (value = "/ hello")

Public String hello () {

List services = discoveryClient.getServices ()

For (String s: services) {

Log.info (s)

}

Return "hello spring cloud!"

}

@ RequestMapping (value = "/ nice")

Public String nice () {

List services = discoveryClient.getServices ()

For (String s: services) {

Log.info ("gogogo" + s)

}

Return "nice to meet you!"

}

}

4. Create a spring boot startup class

@ EnableEurekaClient

@ SpringBootApplication

Public class SingleProviderApplication {

Public static void main (String [] args) {

SpringApplication.run (SingleProviderApplication.class, args)

}

}

The @ EnableEurekaClient modifier indicates that you want to register with the registry.

5. Start the project and normally register with the Eureka registry. Open the Eureka console and you will see that this service has already appeared.

Create a service consumer

With the service provider, then create a consumer to consume

1. Reference the maven package

Org.springframework.cloud

Spring-cloud-starter-netflix-eureka-client

Org.springframework.boot

Spring-boot-starter-web

Org.springframework.cloud

Spring-cloud-starter-openfeign

Org.springframework.boot

Spring-boot-starter-actuator

2. Configure application.yml

Server:

Port: 3002

Eureka:

Client:

ServiceUrl:

DefaultZone: http://127.0.0.1:3000/eureka # # sign in to eureka

Instance:

PreferIpAddress: true

Spring:

Application:

Name: single-customer

3. Start consuming the service interface provided by the provider. Here we demonstrate two consumption methods: one is to use RestTemplate, and the other is to use FeignClient,Feign, which is also open source with Netflix, and is encapsulated in the spring-cloud-starter-openfeign package by Spring Cloud.

Create a startup class and add related comments

@ SpringBootApplication

@ EnableEurekaClient

@ EnableFeignClients

Public class SingleCustomerApplication {

/ * *

* inject RestTemplate

* and use @ LoadBalanced annotation to request the service provider with load balancing strategy

* this is the capability provided by Spring Ribbon

* @ return

* /

@ LoadBalanced

@ Bean

Public RestTemplate restTemplate () {

Return new RestTemplate ()

}

Public static void main (String [] args) {

SpringApplication.run (SingleCustomerApplication.class, args)

}

}

@ EnableEurekaClient declares that this project is an eureka client, and @ EnableFeignClients declares that this project can use Feign.

4. Create a service interface class. This is how Feign is used. For detailed usage, you can check the Spring Cloud Feign related documentation.

/ * *

* IHelloService

* configure the service provider: single-provider is the application.name of the service provider

* /

@ FeignClient ("single-provider")

Public interface IHelloService {

@ RequestMapping (value = "/ hello")

String hello ()

@ RequestMapping (value = "nice")

String nice ()

}

The value annotated by @ FeignClient is the appplication.name of the service provider.

5. Create a Controller to invoke the service

@ RestController

Public class ConsumerController {

@ Autowired

Private RestTemplate restTemplate

@ Autowired

Private IHelloService helloService

Private static final String applicationName = "single-provider"

@ RequestMapping (value = "feignRequest")

Public Object feignRequest () {

String s = helloService.nice ()

Return s

}

@ RequestMapping (value = "commonRequest")

Public Object commonRequest () {

String url = "http://"+ applicationName +" / hello "

String s = restTemplate.getForObject (url,String.class)

Return s

}

}

The feignRequest method invokes the service interface using Feign.

The commonRequest method invokes the service interface with the method provided by RestTemplate

These are all the contents of the article "how to use Spring Cloud's Eureka to achieve service registration". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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