SpringCloud之Feign示例详解

2021-03-19 13:15Bob_F JAVA教程

本篇文章主要介绍了SpringCloud之Feign示例详解，详细的介绍了Feign简介和使用，小编觉得挺不错的，现在分享给大家，也给大家做个参考。一起跟随小编过来看看吧

Feign简介

Feign 是一个声明web服务客户端，这便得编写web服务客户端更容易，使用Feign 创建一个接口并对它进行注解，它具有可插拔的注解支持包括Feign注解与JAX-RS注解，Feign还支持可插拔的编码器与解码器，Spring Cloud 增加了对 Spring MVC的注解，Spring Web 默认使用了HttpMessageConverters, Spring Cloud 集成 Ribbon 和 Eureka 提供的负载均衡的HTTP客户端 Feign.

声明式REST客户端：Feign

先要启动eureka_register_service工程（注册中心）和biz-service-0工程（服务生产者）

创建一个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>

在应用主类中通过@EnableFeignClients注解开启Feign功能

启动文件FeignApplication.java

									@SpringBootApplication

									@EnableDiscoveryClient

									@EnableFeignClients

									public class FeignApplication {

									  public static void main(String[] args) {

									    SpringApplication.run(FeignApplication.class, args);

									  }

									}

定义服务接口类UserClient.java

使用@FeignClient("biz-service-0")注解来绑定该接口对应biz-service-0服务

									@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层中调用上面定义的UserController，具体如下

									@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配置变量

									spring.application.name=feign-consumer

									server.port=8004

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