2、Spring Cloud Alibaba快速整合OpenFeign

    
        springcloudalibaba
        com.example
        0.0.1-SNAPSHOT
    
    4.0.0

    order-openfeign

    
        
            org.springframework.boot
            spring-boot-starter-web
        

        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        

        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
    

package com.example.order.feign;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;


@FeignClient(name = "stock-service",path = "/stock")
public interface StockFeignService {

    
    @RequestMapping("/reduck")
    String reduck();    


    
}

删除不用的restTemplate和添加启动openFeign组件

package com.example.order;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableFeignClients //启动openFeign组件
public class OrderApplication {

    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class,args);
    }
}

package com.example.order.controller;

import com.example.order.feign.StockFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/order")
public class OrderController {

    @Autowired
    private StockFeignService stockFeignService;

    @RequestMapping("/add")
    public String add(){
        System.out.println("下单成功");
        String msg = stockFeignService.reduck();
        return "Hello World " + msg;
    }
}

server:
  port: 8086
#应用名称（nacos会将该名称当做服务名称）
spring:
  application:
    name: order-service
  cloud:
    nacos:
      server-addr: 127.0.0.1:8848
      discovery:
        username: nacos
        password: nacos
        namespace: public

访问：http://localhost:8086/order/add

feign这种远程调用方式它也会自动的帮我们集成ribbon，集成负载均衡器，同样的也会帮我们集成nacos，会根据我@FeignClient(name = “stock-service”,path = “/stock”)注解的name中的服务名去nacos中获取对应的所有的实例，然后在结合负载均衡器来进行调用，feign使用了动态代理。