springCloud学习（⑤）之Feign

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Feign简介

Feign是一个声明式的Web服务客户端，使用Feign可使得Web服务客户端的写入更加方便。 
它具有可插拔注释支持，包括Feign注解和JAX-RS注解、Feign还支持可插拔编码器和解码器、Spring Cloud增加了对Spring MVC注释的支持，并HttpMessageConverters在Spring Web中使用了默认使用的相同方式。Spring Cloud集成了Ribbon和Eureka，在使用Feign时提供负载平衡的http客户端。

声明式REST客户端：Feign

client项目POM添加依赖：

<dependencies>
		<dependency><!-- 自己定义的api -->
			<groupId>com.atguigu.springcloud</groupId>
			<artifactId>microservicecloud-api</artifactId>
			<version>${project.version}</version>
		</dependency>

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</artifactId>
		</dependency>

		<!-- Ribbon相关 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-ribbon</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-config</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- 修改后立即生效，热部署 -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>springloaded</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
		</dependency>
	</dependencies>

公共API项目添加pom依赖：

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</artifactId>
		</dependency>

新建Feign接口： 添加FeignClient客户端，value为调用微服务的服务端名称

@FeignClient(value = "MICROSERVICECLOUD-DEPT")
public interface DeptClientService {
	@RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
	public Dept get(@PathVariable("id") long id);

	@RequestMapping(value = "/dept/list", method = RequestMethod.GET)
	public List<Dept> list();

	@RequestMapping(value = "/dept/add", method = RequestMethod.POST)
	public boolean add(Dept dept);
}

Client Controller添加service：private DeptClientService service;

@RestController
public class DeptController_Consumer {

	@Autowired
	private DeptClientService service;

	@RequestMapping(value = "/consumer/dept/add")
	public boolean add(Dept dept) {
		return service.add(dept);
	}

	@RequestMapping(value = "/consumer/dept/get/{id}")
	public Dept get(@PathVariable("id") Long id) {
		return service.get(id);
	}

	@RequestMapping(value = "/consumer/dept/list")
	public List<Dept> list() {
		return service.list();
	}

}

client 添加@EnableFeignClients注解：

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients(basePackages="com.atguigu.springcloud")
@ComponentScan("com.atguigu.springcloud")
public class DeptConsumer80_Feign_App {

	public static void main(String[] args) {
		SpringApplication.run(DeptConsumer80_Feign_App.class, args);

	}

}

application.yml配置：

server:
  port: 80
  

eureka:
  client:
    register-with-eureka: false
    service-url: 
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/

到此Feign配置完毕