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This article mainly explains "what is the process of building a springCloud project". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what is the springCloud project building process?"

Implement remote invocation across services (RestTemplate)

Business scenario: display user information in the returned order information data

Implementation idea: remote call based on http request initiated by RestTemplate

1. Register for RestTemplate

/ / register RestTemplate's Bean @ Bean public RestTemplate restTemplate () {return new RestTemplate ();} in the startup class of order-service

two。 Revamping OrderController

2.1Inject RestTemplate

@ Autowiredprivate RestTemplate restTemplate

2.2: modify the business code

@ GetMapping ("{orderId}") public Order queryOrderByUserId (@ PathVariable ("orderId") Long orderId) {/ / query the order according to id and return Order order = orderService.queryOrderById (orderId); / / use RestTemplate to initiate a http request to query user information User user = restTemplate.getForObject ("http://localhost:8091/user/" + order.getUserId (), User.class) / / encapsulate user information into the returned value order.setUser (user); return order;}

Providers and consumers

Service provider: a user micro service in a business that is called by other micro services (providing interfaces to other micro services)

Service consumer: in a business, the order micro-service that invokes other micro-services (invokes the interfaces provided by other micro-services)

Service An invokes service B, service B invokes service C, so what is the role of service B?

Answer: depending on who B is relative to, a service can be both a provider and a consumer, because the roles of the provider and the consumer are relative.

Eureka registry

Internal coordination principle

How can consumers get specific information about service providers?

1. The service provider registers its own information with eureka when it starts

2.eureka saves this information

3. Consumers pull provider information from eureka based on service name

If there are multiple service providers, how should consumers choose?

1. Service consumers use load balancing algorithm to pick one from the list of services.

How do consumers perceive the health status of service providers?

1. The service provider will send a heartbeat request to eurekaServer every 30 seconds to report its health status.

2.eureka will update the list of recording services, and abnormal heartbeats will be removed.

3. Consumers can get the latest information.

Eeruka principle

In Eureka architecture, there are two types of micro-service roles

1:EurekaServer: server registry

Record service information

Heartbeat monitoring

2:EurekaClient: client

Privider: service provider, user-service in the case

Register your own information with EurekaServer

Send a heartbeat to EurekaServer every 30s

Consumer: order-service in the case of service consumers

Pull the list of services from EurekaServer based on the service name

Do load balancing based on service list, select a microservice and initiate remote invocation

Set up Eeruka

1. Create a project to introduce spring-cloud-starter-netflix-eureka-server dependencies

Org.springframework.cloud spring-cloud-starter-netflix-eureka-server

two。 Write startup classes and add @ EnableEurekaServer annotations

3. Add the application.yml file and write the following configuration

Server:

Port: 10086 # service port

Spring:

Application:

Name: service name of eurekaserver # eureka

Eureka:

Client:

Service-url: # eureka address information

DefaultZone: http://127.0.0.1:10086/eureka

Eeruka- service registration

Register the user-service service with EurekaServer

1. Introducing spring-cloud-starter-netflix-eureka-client dependencies into user-service projects

Org.springframework.cloud spring-cloud-starter-netflix-eureka-client

two。 In the application.yml file, write the following configuration

Spring:

Application:

Name: the service name of the userservice # eureka client

Eureka:

Client:

Service-url: # eureka address information

DefaultZone: http://127.0.0.1:10086/eureka

Register the order-service service with EurekaServer to repeat the above 1 and 2 operations Eeruka- service discovery

Complete the service pull in order-service

Service pull gets the service list based on the service name, and then load balances the service class table.

1. Modify the OrderService code, modify the access url path, and use the service name instead of ip, port

String url= "http://userservice/user/"+order.getUerId();

two。 Add load balancing annotations to RestTemplate in the startup class OrderApplication of the order-service project

@ Bean

@ LoadBalanced / * added comments * /

Public RestTemplate restTemplate () {

Return new RestTemplate ()

}

At this point, I believe you have a deeper understanding of "what is the springCloud project building process". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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