"Micro-Service Architecture" Springcloud Feign (v)

Feign introduction

Feign is a declarative Web service client, which makes it easier to write Web service clients, create an interface with feign and annotate it, with pluggable annotation support including feign annotations and jax-rs annotations, feign also supports pluggable encoders and decoders, Spring Cloud adds annotations to spring MVC, with the spring Web using Httpmessageconverters, the Spring cloud integrated with the load-balanced HTTP client provided by the Ribbon and Eureka Fei Enl

Declarative rest Client: Feign

Start eureka_register_service Engineering (Registration Center) and biz-service-0 project (service producer) first

Create a MAVEN project Eureka_feign_client

Pom.xml

<parent><groupId>org.springframework.boot</groupId><artifactId> Spring-boot-starter-parent</artifactid><version>1.4.3.release</version><relativepath/>  <!-- lookup parent from repository --></parent><properties> <project.build.sourceencoding>utf-8</project.build.sourceencoding><java.version>1.8</ java.version></properties><dependencies>    <dependency>         <groupId>org.springframework.cloud</groupId>         <artifactId>spring-cloud-starter-feign</artifactId>     </dependency>    <dependency>         <groupId>org.springframework.cloud</groupId>         <artifactid>spring-cloud-starter-eUreka</artifactid>    </dependency>    <dependency>         <groupId>org.springframework.boot</groupId>         <artifactId>spring-boot-starter-web</artifactId>     </dependency>    <dependency>         <groupId>org.springframework.boot</groupId>         <artifactId>spring-boot-starter-test</artifactId>         <scope>test</scope>    </dependency></dependencies> <dependencyManagement>    <dependencies>         <dependency>    <groupId>org.springframework.cloud</groupId>    &nbsP;<artifactid>spring-cloud-dependencies</artifactid>    <version> brixton.sr5</version>    <type>pom</type>    < scope>import</scope></dependency>    </dependencies></ Dependencymanagement>

Turn on the feign feature with @enablefeignclients annotations in the application main class

Startup file Feignapplication.java

@SpringBootApplication @enablediscoveryclient@enablefeignclientspublic class Feignapplication {public static void    Main (string[] args) {Springapplication.run (feignapplication.class, args); }}

Defining the Service Interface class Userclient.java

Use @feignclient ("biz-service-0") annotations to bind the interface corresponding to the BIZ-SERVICE-0 service

@FeignClient ("biz-service-0") public interface Userclient {@RequestMapping (method = requestmethod.get, value = "/getuse        R ") public User getuserinfo ();        @RequestMapping (method = requestmethod.get, value = "/getuser") public String getuserinfostr (); @RequestMapping (method = requestmethod.get, value = "/info") public String info ();}

Call the Usercontroller defined above in the Web layer, as follows

@RestControllerpublic  class UserController {     @Autowired      UserClient userClient;     @RequestMapping (value =  "/getuserinfo ",  method = requestmethod.get)     public user getuserinfo ()   {        return userclient.getuserinfo ();     }         @RequestMapping (value =  "/getuserinfostr",  Method = requestmethod.get)     public string getuserinfostr ()  {         return userclient.getuserinfostr ();     }         @RequestMapping (value =  "/info",  method  = requestmethod.get)     public string info ()  {        &Nbsp;return userclient.info ();     }} 

Application.properties Configuration variables

spring.application.name=feign-consumerserver.port=8004eureka.client.serviceurl.defaultzone=http://localhost:8000/eureka/

Visit http://127.0.0.1:8004/getuserinfo

Summarize:

In fact, the HTTP invocation service method is encapsulated by feign, which allows the client to invoke the method directly as if it were a local method, similar to how the remote service is exposed in Dubbo, except that Dubbo is based on the private binary protocol, and feign is essentially an HTTP client

"Micro-Service Architecture" Springcloud Feign (v)