第三篇:服务消费者(Feign)(Finchley版本)
作者:互联网
一、Feign简介
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、准备工作
继续用上一节的工程, 启动eureka-server,端口为8761; 启动service-hi 两次,端口分别为8762 、8773
简述:
- 1个eureka服务注册中心
- 2个发布服务的服务端
三、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的启动依赖spring-cloud-starter-netflix-eureka-client、Web的启动依赖spring-boot-starter-web,代码如下:
<?xml version="1.0" encoding="UTF-8"?>
<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>
<parent>
<groupId>com.gblfy</groupId>
<artifactId>sc-f-chapter3</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<groupId>com.gblfy</groupId>
<artifactId>service-feign</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>service-feign</name>
<description>Demo project for Spring Boot</description>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</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http://localhost:8761/eureka/ ,代码如下:
eureka:
client:
serviceUrl:
defaultZone: http://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:
package com.gblfy.servicefeign;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableDiscoveryClient
@EnableEurekaClient
@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 {
@GetMapping(value = "/hi")
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 {
@Autowired
SchedualServiceHi schedualServiceHi;
@GetMapping(value = "/hi")
public String sayHi(@RequestParam String name) {
return schedualServiceHi.sayHiFromClientOne(name);
}
// 测试链接:http://localhost:8765/hi?name=gblfy
}
启动程序,多次访问http://localhost:8765/hi?name=gblfy,浏览器交替显示:
hi forezp,i am from port:8762
hi forezp,i am from port:8763
本文源码下载:
https://github.com/gb-heima/springcloud-practical-column/tree/master/sc-f-chapter3
标签:Feign,第三篇,spring,springframework,Finchley,hi,org,cloud 来源: https://blog.csdn.net/weixin_40816738/article/details/90053634