Spring Cloud入门系列（七）- 负载均衡之Open Feign

OpenFeign是什么

OpenFeign能做什么

OpenFeign和Feign的区别

如何使用

代码演示

定义新的模块 cloud-consumer-openfeign-order80

pom.xml

<?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>cloud201230</artifactId>
        <groupId>com.banana</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

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

    <dependencies>
        <!--引入自定义的api通用包，可以使用Payment支付Entity-->
        <dependency>
            <groupId>com.banana</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--引入eureka客户端-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!--open feign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <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>
        <!--热部署-->
        <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>
    </dependencies>
</project>

application.yml

server:
  port: 80

eureka:
  client:
    #是否将自己注册到注册中心, 默认true
    register-with-eureka: false
    #是否从EurekaServer抓取已有的注册信息,单机无所谓,集群必须设置为true配合ribbon使用负载均衡
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:7001/eureka  #单机版
      #defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka #集群版

#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时间,适用于网络状况正常情况下,两端连接所用时间
  ReadTimeout: 5000
  #指的是连接建立后,从服务器获取到可用资源所用时间
  ConnectTimeout: 5000

#feign 日志以什么级别监控那个接口
logging:
  level:
    com.banana.springcloud.service: debug

主启动类上，添加@EnableFeignClients注解

package com.banana.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;
/**
 * @author layman
 * @date 2021/1/17
 */
@SpringBootApplication
@EnableFeignClients
public class OpenFeignOrder80 {
    
    
    public static void main(String[] args) {
    
    
            SpringApplication.run(OpenFeignOrder80.class,args);
        }
}

使用 接口+注解 的形式，调用服务

package com.banana.springcloud.service;

import com.banana.springcloud.entity.CommonResult;
import com.banana.springcloud.entity.Payment;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * FeignClient注解中的value属性指定了要调用的{服务}名
 * @author layman
 * @date 2021/1/17
 */
@Component
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface OpenFeignOrderService {
    
    

    /**
    * 查询payment
    * @param id：主键
    * @return CommonResult<Payment>
    */
    @GetMapping(value = "/payment/get/{id}")
    CommonResult<Payment> getPaymentById(@PathVariable("id") Long id);

    /**
    * 模拟openFeign访问超时
    * @return String
    */
    @GetMapping("/payment/openfeign/timeout")
    String openFeignTimeOut();
}

@FeignClient(value = “CLOUD-PAYMENT-SERVICE”) ：表示 该接口调用的是CLOUD-PAYMENT-SERVICE

当访问getPaymentById()方法时，就相当于访问：http://cloud-payment-service/payment/get/{id}

---

OpenFeignOrderController

package com.banana.springcloud.controller;

import com.banana.springcloud.entity.CommonResult;
import com.banana.springcloud.entity.Payment;
import com.banana.springcloud.service.OpenFeignOrderService;
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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @author layman
 * @date 2021/1/17
 */
@RestController
@Slf4j
@RequestMapping("/consumer/payment")
public class OpenFeignOrderController {
    
    

    @Resource
    private OpenFeignOrderService openFeignOrderService;

    @GetMapping("/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id){
    
    
        return openFeignOrderService.getPaymentById(id);
    }
    /**
     * openfeign-ribbon 客户端一般默认等待1秒钟
     */
    @GetMapping("/openfeign/timeout")
    public String TestOpenFeignTimeOut(){
    
    
        return openFeignOrderService.openFeignTimeOut();
    }
}