SpringCloud06

feign使用
快速入门

package cn.itcast.service;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

//@SpringBootApplication
//@EnableDiscoveryClient
//@EnableCircuitBreaker //开启熔断
@SpringCloudApplication //组合注解，相当于@SpringBootApplication，@EnableDiscoveryClient，@EnableCircuitBreaker
@EnableFeignClients //启用feign组件
public class ItcastServiceConsumerApplication {

//    @Bean
//    @LoadBalanced
//    public RestTemplate restTemplate(){
//        return new RestTemplate();
//    }

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

}

package cn.itcast.service.client;

import cn.itcast.service.pojo.User;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@FeignClient("service-provide") //声明一个接口是一个feign接口，指定服务id
public interface UserClient {
    @GetMapping("user/{id}")
    public User qusetyUserById(@RequestParam("id")Long id);
}

package cn.itcast.service.controller;

import cn.itcast.service.client.UserClient;
import cn.itcast.service.pojo.User;
import javafx.beans.DefaultProperty;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.client.RestTemplate;

import java.util.List;

@Controller
@RequestMapping("consumer/user")
//@DefaultProperties(defaultFallback = "qusetyUserByIdFallback")
public class UserController {
    @Autowired
    private UserClient userClient;
//    @Autowired
//    private RestTemplate restTemplate;

//    @Autowired
//    private DiscoveryClient discoveryClient; //包含了拉取的所有服务信息

    @GetMapping
    @ResponseBody
    @HystrixCommand
    public String qusetyUserById(@RequestParam("id")Long id){
//        if (id == 1){
//            throw new RuntimeException();
//        }
//        List<ServiceInstance> instances = discoveryClient.getInstances("service-provider");
//        ServiceInstance instance = instances.get(0);
        return this.userClient.qusetyUserById(id).toString();
    }

    public String qusetyUserByIdFallback(Long id){
        return "服务正忙，稍后再试";
    }
}

熔断

server:
  port: 80
spring:
  application:
    name: service-consumer
  eureka:
    client:
      service-url:
        defaultZone: http://localhost:10086/eureka
      fetch-registry: true #拉取服务列表，缓存到本地
      registry-fetch-interval-seconds: 5 #拉取列表的间隔时间
service-provider: #服务提供方的服务id
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule #调用随机算法
hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMillisecond: 6000 # 设置hystrix的超时时间为6000ms
feign:
  hystrix:
    enabled: true # 开启Feign的熔断功能

package cn.itcast.service.client;

import cn.itcast.service.pojo.User;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestParam;

@Component
public class UserClientFallback implements UserClient {
    @Override
    public User qusetyUserById(Long id){
        User user = new User();
        user.setUserName("服务器正忙，请稍后再试");
        return user;
    }
}

package cn.itcast.service.client;

import cn.itcast.service.pojo.User;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@FeignClient("service-provide", fallback = UserFeignClientFallback.class)
public interface UserClient {
    @GetMapping("user/{id}")
    public User qusetyUserById(@RequestParam("id")Long id);
}