java B2B2C Springboot仿淘宝电子商城系统-负载均衡之ribbon+feign

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。
需要JAVA Spring Cloud大型企业分布式微服务云构建的B2B2C电子商务平台源码 一零三八七七四六二六
简而言之：
Feign 采用的是基于接口的注解
Feign 整合了ribbon

二、创建一个feign的服务
1）新建一个Springboot项目service-feign，它的pom.xml文件如下

<?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> <groupId>com.example</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>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.4.0.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-feign</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> <repositories> <repository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories> </project>

2）配置application.yml

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

3）feign-service的启动类，在启动类上添加@EnableDiscoveryClient @EnableFeignClients 注解，表示用注解开启feign功能。如果标注了@FeignClient的接口和启动类不在一个包下，应该在@EnableFeignClient()中添加所在包

package com.example.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.netflix.feign.EnableFeignClients; @EnableFeignClients @EnableDiscoveryClient @SpringBootApplication 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。比如在代码中调用了hello-service服务的“/hello”接口，代码如下，在启动该项目时，@EnableFeignClients注解就会让Feign在指定包下扫描所有标注了@FeignClient的接口

package com.liantong.service; import org.springframework.cloud.netflix.feign.FeignClient; import org.springframework.web.bind.annotation.RequestMapping; @FeignClient("service-helloworld") //向注册中心申请使用service-helloworld客户端 public interface HelloService { @RequestMapping("/hello") //表明使用service-helloworld中的“/hello方法” String sayHelloFromClient(); } 

5）controller层

package com.liantong.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import com.liantong.service.HelloService; @Controller public class HelloController { @Autowired private HelloService hs; @RequestMapping("/hello") @ResponseBody public String hello() { return hs.sayHelloFromClient(); } }

6）依次启动eureka-server，两个service-helloworld，再启动本项目，完成！
java B2B2C Springboot仿淘宝电子商城系统