Feign是一个声明式的伪Http客户端,它使得写Http客户端变得更简单。使用Feign只需要创建一个接口并添加注解,可以使用Feign注解和JAX-RS注解。Feign默认集成了Ribbon,并和Eureka结合。
1、启动eureka-server,端口为8761.启动service-hi两次,端口分别为8762、8763.
2、创建一个feign的服务。
(1)新建一个spring-boot工程,取名为service-feign,在它的pom文件引入Feign的起步依赖spring-cloud-starter-feign,eureka的起步依赖spring-cloud-starter-netflix-eureka-client, web的起步依赖spring-boot-starter-web
4.0.0
com.forezp
service-feign
0.0.1-SNAPSHOT
jar
service-feign
Demo project for Spring Boot
com.forezp
sc-f-chapter3
0.0.1-SNAPSHOT
org.springframework.cloud
spring-cloud-starter-netflix-eureka-client
org.springframework.boot
spring-boot-starter-web
org.springframework.cloud
spring-cloud-starter-openfeign
(2)在工程 的配置文件application.yml文件,指定程序名为service-feign,端口为8765,服务注册地址为http://localhost:8761/eureka/
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8765
spring:
application:
name: service-feign
(3)在程序的启动类ServiceFeignApplication,加上@EnableFeignClient注解开启Feign的功能。
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableFeignClients
public class ServiceFeignApplication {
public static void main(String[] args) {
SpringApplication.run( ServiceFeignApplication.class, args );
}
}
(4)定义一个feign接口,通过@FeignClient("服务名")来指定调用哪个服务。
@FeignClient(value = "service-hi")
public interface SchedualServiceHi {
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);
}
(5)在Web层的controller层,对外暴露一个“/hi”的API接口,通过上面定义的Feign客户端SchedualServiceHi来消费服务。
@RestController
public class HiController {
//编译器报错,无视。 因为这个Bean是在程序启动的时候注入的,编译器感知不到,所以报错。
@Autowired
SchedualServiceHi schedualServiceHi;
@GetMapping(value = "/hi")
public String sayHi(@RequestParam String name) {
return schedualServiceHi.sayHiFromClientOne( name );
}
}
启动程序,多冷饮访问http://localhost:8765/hi?name=xxx