[Java知识库]Springcloud 集成 Feign

Feign 整合了 Ribbon 与 Hystrix，同时还提供了一种声明式的 Webservice?客户端定义的方式。?

Springcloud 集成 Nacos注册中心

Provider?服务提供者

参考?Springcloud 集成 Nacos简单服务调用

Consumer 消费者

?pom.xml

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.2.2.RELEASE</version>
        </dependency>

启动类

package com.lhy.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

// 开启Feign
@EnableFeignClients
@SpringBootApplication
@EnableDiscoveryClient
public class CloudApiApplication {

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

本地Feign客户端

package com.lhy.cloud.client;

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


@FeignClient(name = "user-api", path = "/user")
public interface UserClient {

    @GetMapping("/headPortrait")
    String headPortrait();

}

测试类

package com.lhy.cloud.controller;

import com.lhy.cloud.client.UserClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * Class description.
 *
 * @author ocean liu
 * @createTime 2021/11/29 - 10:57
 */
@RequestMapping("/cloud")
@RestController
public class CloudController {

    @Resource
    private UserClient userClient;

    @RequestMapping("/user/headPortrait")
    public String getUserHeadPortrait() {
        return userClient.headPortrait();
    }
}

验证

负载均衡配置

pom.xml 配置负载策略

user-api:
  ribbon:
    # com.netflix.loadbalancer.RoundRobinRule           默认 轮询
    # com.netflix.loadbalancer.RandomRule               随机
    # com.netflix.loadbalancer.BestAvailableRule        最小并发
    # com.netflix.loadbalancer.WeightedResponseTimeRule 响应时间 权重
    # com.netflix.loadbalancer.ZoneAvoidanceRule        复合判读 区域性能也服务可用性
    # com.netflix.loadbalancer.RetryRule                失败重试
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RoundRobinRule

熔断配置

pom.xml 开启熔断器

feign:
  hystrix:
    enabled: true

重新编写本地Feign客户端，配置fallback

package com.lhy.cloud.client;

import com.lhy.cloud.client.fallback.UserClientFallback;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;


@FeignClient(name = "user-api", path = "/user", fallback = UserClientFallback.class)
public interface UserClient {

    @GetMapping("/headPortrait")
    String headPortrait();

}

编写fallback处理类

package com.lhy.cloud.client.fallback;

import com.lhy.cloud.client.UserClient;
import org.springframework.stereotype.Component;

/**
 * Class description.
 *
 * @author ocean liu
 * @createTime 2021/12/9 - 9:54
 */
@Component
public class UserClientFallback implements UserClient {

    @Override
    public String headPortrait() {
        return "default.png";
    }
}

测试关闭provider服务

测试开启provider服务