springcloud 服務消費者
阿新 • • 發佈:2018-12-18
簡介
Feign是一個宣告式的偽Http客戶端,它使得寫Http客戶端變得更簡單。使用Feign只需要建立一個介面並添加註解,可以使用Feign註解和JAX-RS註解。Feign預設集成了Ribbon,並和Eureka結合。
實踐
1、啟動eureka-server,埠為8761.啟動service-hi兩次,埠分別為8762、8763.
2、建立一個feign的服務。
(1)新建一個spring-boot工程,取名為service-feign,在它的pom檔案引入Feign的起步依賴spring-cloud-starter-feign,eureka的起步依賴spring-cloud-starter-netflix-eureka-client, web的起步依賴spring-boot-starter-web
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.forezp</groupId> <artifactId>service-feign</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>service-feign</name> <description>Demo project for Spring Boot</description> <parent> <groupId>com.forezp</groupId> <artifactId>sc-f-chapter3</artifactId> <version>0.0.1-SNAPSHOT</version> </parent> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> </dependencies> </project>
(2)在工程 的配置檔案application.yml檔案,指定程式名為service-feign,埠為8765,服務註冊地址為http://localhost:8761/eureka/
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8765
spring:
application:
name: service-feign
(3)在程式的啟動類ServiceFeignApplication,加上@EnableFeignClient註解開啟Feign的功能。
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@EnableFeignClients
public class ServiceFeignApplication {
public static void main(String[] args) {
SpringApplication.run( ServiceFeignApplication.class, args );
}
}
(4)定義一個feign介面,通過@FeignClient("服務名")來指定呼叫哪個服務。
@FeignClient(value = "service-hi")
public interface SchedualServiceHi {
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);
}
(5)在Web層的controller層,對外暴露一個“/hi”的API介面,通過上面定義的Feign客戶端SchedualServiceHi來消費服務。
@RestController
public class HiController {
//編譯器報錯,無視。 因為這個Bean是在程式啟動的時候注入的,編譯器感知不到,所以報錯。
@Autowired
SchedualServiceHi schedualServiceHi;
@GetMapping(value = "/hi")
public String sayHi(@RequestParam String name) {
return schedualServiceHi.sayHiFromClientOne( name );
}
}
啟動程式,多冷飲訪問http://localhost:8765/hi?name=xxx