SpringCloud-feignfeign简介 Feign是一个声明式的web service客户端，它使得编写web

feign简介

Feign是一个声明式的web service客户端，它使得编写web service客户端更为容易。
创建接口，为接口添加注解，即可使用Feign。
Feign旨在使编写Java Http客户端变得更容易

简单使用

导入依赖

        <!-- fregin -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

编写接口

package springcloud.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import springcloud.pojo.Dept;

import java.util.List;

//@FeignClient 标注这是feign，value填的是服务名
@FeignClient(value = "springcloud-provider")
@Service
public interface DeptFeignService {
    // 请求的路径需与服务提供者的路径一致
    @RequestMapping(value = "/provider/add")
    public boolean add(Dept dept);

    @RequestMapping(value = "/provider/get/{id}")
    public Dept queryByID(@PathVariable("id") Long id);

    @RequestMapping(value = "/provider/query")
    public List<Dept> queryAll();

}

编写业务层

package springcloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import springcloud.pojo.Dept;
import springcloud.service.DeptFeignService;

import java.util.List;

@RestController
public class DeptController {

    @Autowired
    private DeptFeignService deptFeignService;

    @RequestMapping("/consumer/add")
    public boolean add(Dept dept){
        return this.deptFeignService.add(dept);
    }

    @RequestMapping("/consumer/get/{id}")
    public Dept get(@PathVariable("id") Long id){
        return this.deptFeignService.queryByID(id);
    }

    @RequestMapping("/consumer/query")
    public List<Dept> query(){
        return this.deptFeignService.queryAll();
    }

}

在主启动类添加开启feign负载均衡的注解@EnableFeignClients(basePackages = {"springcloud.service"})，basePackages扫描注解
开启服务进行测试

feign VS ribbon

微服务名字 --> ribbon
接口和注解 --> feign
Feign默认集成了Ribbon
Feign是面向接口编程，更加符合java程序员的编程习惯，当然各有各的好处，可以根据个人习惯而定，如果喜欢REST风格使用Ribbon；如果喜欢社区版的面向接口风格使用Feign.