feign

Feign使用了Ribbon的负载均衡功能，大大简化了远程调用时的代码

String url ="http://dept-provider/get?name="+name; 
String forObject = template.getForObject(url, String.class);

1.使用feign改造consumer工程

1.引入依赖

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

2.开启feign功能

@SpringBootApplication
@EnableFeignClients //开启feign客户端 
public class ConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class, args);
    }
}

3.删除RestTemplate

feign已经自动集成了Ribbon负载均衡的RestTemplate。所以，此处不需要再注册

RestTemplate。

4.创建Feign客户端 service层

package com.jd.service;

@FeignClient("address-provider")
public interface IAddressService {
    @GetMapping("/address/list/{userId}")
    List<Address> getByUserId(@PathVariable("userId") String userId);
}

5.修改consumer的controller

package com.jd;

@Controller
public class OrderController {

    @Autowired
    private IAddressService addressService;
    @ResponseBody
    @RequestMapping("/order/info.do")
    public Map<String,Object> info(String userId) {
        Map<String,Object> map = new HashMap<>();
        map.put("addressList",addressService.getByUserId(userId));
        map.put("goodsList",null);
        return map;
    }
}

6.在服务层做一下操作

配置文件更改

# 应用名称
spring.application.name=address-provider
# 应用服务 WEB 访问端口
server.port=7777

#指定Eureka注册中心访问地址
eureka.client.serviceUrl.defaultZone=http://127.0.0.1:5555/eureka

#是否从Eureka注册中心抓取已有的注册消息，默认为true，单节点无所谓true或false，但是集群必须设置为true才能配合ribbon使用负载均衡
eureka.client.fetch-registry=true

controller层修改

package com.jd;

@Controller
public class AddressController {

    @Autowired
    private IAddressService addressService;

    @ResponseBody
    @GetMapping("/address/list/{userId}")
    public List<Address> list(@PathVariable("userId") String userId) {
        return addressService.getByUserId(userId);
    }
}