springcloud（三）openFeign对微服务的调用以及负载均衡

openFeign相当于Ribbon+restTemplate，都是对微服务的调用以及负载均衡，其中openFeign有对Ribbon的封装，并且openFeign的用法也更符合面向接口开发的初衷
openFeign是用于客户端的
下面是对openFeign的配置：
项目目录

pom文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>com.zzuli.springcloud</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloud-consumer-feign-order80</artifactId>

    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--eureka client-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--web-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!--一般基础通用配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>



</project>

yml文件
其中
http://eureka7001.com:7001/eureka/
http://eureka7002.com:7002/eureka/
是两个Eureka的注册中心

server:
  port: 80

eureka:
  client:
    register-with-eureka: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/
##设置feign客户端超时时间(OpenFeign默认支持ribbon)
#ribbon:
##指的是建立连接所用的时间，适用于网络状况正常的情况下,两端连接所用的时间
#  ReadTimeout: 5000
##指的是建立连接后从服务器读取到可用资源所用的时间
#  ConnectTimeout: 5000

logging:
  level:
    # feign日志以什么级别监控哪个接口
    com.zzuli.springcloud.service.PaymentFeignService: debug

config类
用于打印日志

package com.zzuli.springcloud.config;

import feign.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 日志
 */
@Configuration
public class FeignConfig
{
    @Bean
    Logger.Level feignLoggerLevel()
    {
        return Logger.Level.FULL;
    }
}

Service服务接口

CLOUD-PAYMENT-SERVICE
是在服务中心注册的服务名称

package com.zzuli.springcloud.service;

import com.zzuli.springcloud.entities.CommonResult;
import com.zzuli.springcloud.entities.Payment;
import feign.Param;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

@Service
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeignService {

    @GetMapping("/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id);
}

Controller类

package com.zzuli.springcloud.controller;

import com.zzuli.springcloud.entities.CommonResult;
import com.zzuli.springcloud.service.PaymentFeignService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
@Slf4j
public class OrderFeignController {

    @Resource
    private PaymentFeignService paymentFeignService;

    @GetMapping("/consumer/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id){
        return paymentFeignService.getPaymentById(id);
    }
}

启动类

package com.zzuli.springcloud;

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

@SpringBootApplication
@EnableFeignClients   //使用feign
public class OrderFeignMain80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderFeignMain80.class,args);
    }
}

效果展示