Springcloud Spring Boot mybatis distributed micro-service Cloud Architecture (III): service delivery and invocation

Previous article we introduced the Eureka Service registry, this article describes how to use the Eureka Service registry to build a simple service-side registration service, the client to invoke the service use case.

There are three roles in the case: the Service registry, the service provider, the service consumer, the service registry is our previous Eureka stand-alone launch, the process is to start the registry, service provider production services and registered in the service center, consumers from the service center to obtain services and execution.

Services provided

We assume that the service provider has a Hello method that can provide the service of the output "Hello Xxx,this is first Messge" based on the parameters passed in

1, POM package configuration

To create a Springboot project, add the following configuration to the Pom.xml:

<dependencies>    <dependency>        <groupId>org.springframework.cloud</groupId>        <artifactId>spring-cloud-starter-eureka</artifactId>    </dependency>    <dependency >        <groupId>org.springframework.boot</groupId>        <artifactId> spring-boot-starter-test</artifactid>        <scope>test</scope>    </dependency></ Dependencies>

2. Configuration files

The application.properties configuration is as follows:

spring.application.name=spring-cloud-producerserver.port=9000  Eureka.client.serviceUrl.defaultZone=http://localhost:8000/eureka/

The parameters have been explained in the previous article, and there is not much to say here.

3. Startup class

To add annotations to the startup class @EnableDiscoveryClient

@SpringBootApplication @enablediscoveryclient  Public class producerapplication {     publicstaticvoid  main (string[] args) {        Springapplication.run (producerapplication. class , args);}    }

4. Controller

Provide Hello Service

@RestController  Public class Hellocontroller {        @RequestMapping ("/hello")    public  String Index (@ Requestparam String name) {        return "Hello" +name+ ", this is first Messge";    }}

@EnableDiscoveryClientWhen you add annotations, the project has the functionality to register the service. Once the project is started, you can see the Spring-cloud-producer service on the Registration Center page.

The service provider configuration is complete.

Service Call 1, POM package configuration

Consistent with service providers

<dependencies>    <dependency>        <groupId>org.springframework.cloud</groupId>        <artifactId>spring-cloud-starter-eureka</artifactId>    </dependency>    <dependency >        <groupId>org.springframework.boot</groupId>        <artifactId> spring-boot-starter-test</artifactid>        <scope>test</scope>    </dependency></ Dependencies>

2. Configuration files

The application.properties configuration is as follows:

spring.application.name=spring-cloud-consumerserver.port=9001  Eureka.client.serviceUrl.defaultZone=http://localhost:8000/eureka/

3. Startup class

Start class additions @EnableDiscoveryClient and @EnableFeignClients annotations.

@SpringBootApplication @enablediscoveryclient@enablefeignclients  Public class consumerapplication {     publicstaticvoid  main (string[] args) {        Springapplication.run (consumerapplication. class , args);    } }

• @EnableDiscoveryClient: Enable service registration and discovery
• @EnableFeignClients: Enable feign for remote invocation

Feign is a declarative Web service client. Using feign can make it easier to write a Web service client by defining an interface and then adding annotations to it, as well as supporting annotations of the JAX-RS standard. The feign also supports pluggable encoders and decoders. Spring Cloud encapsulates the feign, enabling it to support Spring MVC standard annotations and httpmessageconverters. The feign can be used in combination with the Eureka and ribbon to support load balancing.

4. Feign Call Implementation

@FeignClient (name= "Spring-cloud-producer")publicinterface  helloremote {     = "/hello")    public string Hello (@RequestParam (value = "Name") string name);} 

• Name: remote service name, and Spring.application.name configuration

The methods in this class and the method names and parameters in Contoller in the remote service need to be consistent.

5. Web layer Invoke remote service

Inject the helloremote into the controller layer and invoke it like a normal method.

@RestController  Public class Consumercontroller {     @Autowired    helloremote helloremote;        @RequestMapping ("/hello/{name}")    public string index (@PathVariable ("Name ") string Name) {        return  Helloremote.hello (name);}    }

In this case, the simplest example of a service registration and invocation is complete.

Test a simple call

Start Spring-cloud-eureka, Spring-cloud-producer, spring-cloud-consumer three items in turn

First Enter: http://localhost:9000/hello?name=neo check whether the Spring-cloud-producer service is normal

Return:hello neo，this is first messge

Description Spring-cloud-producer Normal start, the service provided is also normal.

In the browser, enter:http://localhost:9001/hello/neo

Return:hello neo，this is first messge

Indicates that the client has successfully invoked the remote service hello via feign and returned the result to the browser.

Load Balancing

With the above Spring-cloud-producer as an example of modification, the controller changes as follows:

@RestController  Public class Hellocontroller {        @RequestMapping ("/hello")    public  String Index (@ Requestparam String name) {        return "Hello" +name+ ", this is producer 2  send first Messge"  ;    }}

To change the port in the configuration file:

spring.application.name=spring-cloud-producerserver.port=9003eureka.client.serviceUrl.defaultZone =http://localhost:8000/eureka/

After the package is started, two service providers will be found in Eureka, such as:

Then enter again in the browser: http://localhost:9001/hello/neo to test:

Return results for the first time:hello neo，this is first messge

Second return result:hello neo，this is producer 2 send first messge

Continuous testing will find two results alternating, indicating that the two service centers automatically provide a service load balancing function. If we increase the number of service providers to N, the test results are the same, and the request is automatically polled to each server for processing. Source Source technical support for complete projects 2147775633

Springcloud Spring Boot mybatis distributed micro-service Cloud Architecture (III): service delivery and invocation