iteye02 阅读(14) 评论(0)

社交电商平台源码请加企鹅求求:一零三八七七四六二六。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注解。它具有可插拔的注解特性,可使用Feign 注解和JAX-RS注解。Feign支持可插拔的编码器和解码器。Feign默认集成了Ribbon,并和Eureka结合,默认实现了负载均衡的效果。

简而言之:

Feign 采用的是基于接口的注解

Feign 整合了ribbon,具有负载均衡的能力

整合了Hystrix,具有熔断的能力

二、创建一个feign的服务

新建一个spring-boot工程,取名为serice-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,代码如下:
 

<project xmlns="https://maven.apache.org/POM/4.0.0" xmlns:xsi="https://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="https://maven.apache.org/POM/4.0.0 https://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>
 

在工程的配置文件application.yml文件,指定程序名为service-feign,端口号为8765,服务注册地址为https://localhost:8761/eureka/ ,代码如下:
 

eureka:
client:
serviceUrl:
defaultZone: https://localhost:8761/eureka/
server:
port: 8765
spring:
application:
name: service-feign
 

在程序的启动类ServiceFeignApplication ,加上@EnableFeignClients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 );
}
}
 

定义一个feign接口,通过@ FeignClient(“服务名”),来指定调用哪个服务。比如在代码中调用了service-hi服务的“/hi”接口,代码如下:

 

@FeignClient(value = "service-hi")
public interface SchedualServiceHi {
@RequestMapping(value = "/hi",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);
}
 

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。代码如下:
 

@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,多次访问https://localhost:8765/hi?name=forezp,浏览器交替显示:
 

hi forezp,i am from port:8762

hi forezp,i am from port:8763
 

发表评论
切换编辑模式