SpringCloud之Feign示例詳解

發(fā)布時(shí)間：2020-10-22 13:19:41 來(lái)源：腳本之家閱讀：139 作者：Bob_F 欄目：編程語(yǔ)言

Feign簡(jiǎn)介

Feign 是一個(gè)聲明web服務(wù)客戶(hù)端，這便得編寫(xiě)web服務(wù)客戶(hù)端更容易，使用Feign 創(chuàng)建一個(gè)接口并對(duì)它進(jìn)行注解，它具有可插拔的注解支持包括Feign注解與JAX-RS注解，F(xiàn)eign還支持可插拔的編碼器與解碼器，Spring Cloud 增加了對(duì) Spring MVC的注解，Spring Web 默認(rèn)使用了HttpMessageConverters, Spring Cloud 集成 Ribbon 和 Eureka 提供的負(fù)載均衡的HTTP客戶(hù)端 Feign.

聲明式REST客戶(hù)端：Feign

先要啟動(dòng)eureka_register_service工程（注冊(cè)中心）和biz-service-0工程（服務(wù)生產(chǎn)者）

創(chuàng)建一個(gè)maven工程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>

  <artifactId>spring-cloud-dependencies</artifactId>

  <version>Brixton.SR5</version>

  <type>pom</type>

  <scope>import</scope>

</dependency>

  </dependencies>

</dependencyManagement>

在應(yīng)用主類(lèi)中通過(guò)@EnableFeignClients注解開(kāi)啟Feign功能

啟動(dòng)文件FeignApplication.java

@SpringBootApplication

@EnableDiscoveryClient

@EnableFeignClients

public class FeignApplication {

  public static void main(String[] args) {

    SpringApplication.run(FeignApplication.class, args);

  }
}

定義服務(wù)接口類(lèi)UserClient.java

使用@FeignClient("biz-service-0")注解來(lái)綁定該接口對(duì)應(yīng)biz-service-0服務(wù)

@FeignClient("biz-service-0")

public interface UserClient { 

  @RequestMapping(method = RequestMethod.GET, value = "/getuser")

  public User getuserinfo();   

  @RequestMapping(method = RequestMethod.GET, value = "/getuser")

  public String getuserinfostr();   

  @RequestMapping(method = RequestMethod.GET, value = "/info")

  public String info();
}

在web層中調(diào)用上面定義的UserController，具體如下

@RestController

public 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() {

    return userClient.info();

  }
}

application.properties配置變量

spring.application.name=feign-consumer

server.port=8004

eureka.client.serviceUrl.defaultZone=http://localhost:8000/eureka/

訪問(wèn) http://127.0.0.1:8004/getuserinfo

總結(jié)：

其實(shí)通過(guò)Feign封裝了HTTP調(diào)用服務(wù)方法，使得客戶(hù)端像調(diào)用本地方法那樣直接調(diào)用方法，類(lèi)似Dubbo中暴露遠(yuǎn)程服務(wù)的方式，區(qū)別在于Dubbo是基于私有二進(jìn)制協(xié)議，而Feign本質(zhì)上還是個(gè)HTTP客戶(hù)端

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持億速云。

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SpringCloud之Feign示例詳解

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