SpringCloud系列（26）--OpenFeign超时控制

前言：在上一章节中我们简单的介绍了如何使用OprnFeign去调用微服务，因为消费侧和服务侧是两个不同的微服务，这样可能会出现超时的现象，例如服务侧需要3秒处理任何才能返回结果，但消费侧可能2秒就断开连接了，这时就会因为时间差而出现连接超时的问题，而本节内容则是关于如果去对OpenFeign进行超时控制。

1、编写代码模拟连接超时

(1)编写providder-payment8001项目PaymentController类的代码

package com.ken.springcloud.controller;

import com.ken.springcloud.entities.CommonResult;
import com.ken.springcloud.entities.Payment;
import com.ken.springcloud.service.PaymentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.*;

import javax.annotation.Resource;
import java.util.List;
import java.util.concurrent.TimeUnit;

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @Value("${server.port}")
    private String serverPort;

    @Resource
    private DiscoveryClient discoveryClient;

    @PostMapping("/payment/insert")
    public CommonResult insert(@RequestBody Payment payment) {
        int result = paymentService.insert(payment);
        log.info("插入结果{}",result);
        if(result > 0) {
            return new CommonResult(200,"插入数据库成功，提供服务的端口号为" + serverPort,result);
        }else {
            return new CommonResult(500,"插入数据库失败",result);
        }
    }

    @GetMapping("/payment/get/{id}")
    public CommonResult insert(@PathVariable("id") Long id) {
        Payment payment = paymentService.getPaymentById(id);
        log.info("查询结果{}",payment);
        if(payment != null) {
            return new CommonResult(200,"查询成功，提供服务的端口号为" + serverPort,payment);
        }else {
            return new CommonResult(500,"没有对应的数据，查询失败，查询id" + id,payment);
        }
    }

    @GetMapping("/payment/discovery")
    public Object discovery() {
        //获取eureka内的服务
        List<String> services = discoveryClient.getServices();
        for (String service : services) {
            log.info("***service:" + service);
        }
        //获取服务名为CLOUD-PAYMENT-SERVICE下的实例
        List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
        for (ServiceInstance instance : instances) {
            log.info(instance.getServiceId()+"\t"+instance.getHost()+"\t"+instance.getPort()+"\t"+instance.getUri());
        }
        return this.discoveryClient;
    }

    @GetMapping("/payment/lb")
    public String getPaymentLB() {
        //返回当前服务的端口号
        return serverPort;
    }

    @GetMapping("/payment/feign/timeout")
    public String paymentFeigntimeout() {
        try {
            TimeUnit.SECONDS.sleep(3);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //返回当前服务的端口号
        return serverPort;
    }

}

(2)编写cloud-consumer-feign-order80项目PaymentFeignService类的代码

package com.ken.springcloud.service;

import com.ken.springcloud.entities.CommonResult;
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;

@Component
//这里@FeignClient里写的是指定要访问的微服务的名称，表示通过FeignClient去Eureka上面找名称为CLOUD-PAYMENT-SERVICE的微服务的接口
@FeignClient(value = "CLOUD-PAYMENT-SERVICE")
public interface PaymentFeignService {

    //指明要调用的CLOUD-PAYMENT-SERVICE的微服务的接口，这里调用的是PaymentController类里的/payment/get/{id}接口
    @GetMapping("/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id);

    @GetMapping("/payment/feign/timeout")
    public String paymentFeigntimeout();
}

(3)编写cloud-consumer-feign-order80项目OrderFeignController的代码

package com.ken.springcloud.controller;

import com.ken.springcloud.entities.CommonResult;
import com.ken.springcloud.entities.Payment;
import com.ken.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;

@Slf4j
@RestController
public class OrderFeignController {

    @Resource
    private PaymentFeignService paymentFeignService;

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

    @GetMapping("/payment/feign/timeout")
    public String paymentFeigntimeout() {
        //客户端一般默认等待1秒钟
        return paymentFeignService.paymentFeigntimeout();
    }

}

2、测试payment接口是否正常工作

分别启动eureka-server7001、eureka-server7002，然后再启动provider-payment8001，最后再启动cloud-consumer-feign-order80，全部启动完毕后在浏览器的地址栏里输入http://localhost:8001/payment/feign/timeout 并且回车调用接口，最后可以看到接口调用成功并返回8001，这证明provider-payment8001服务工作正常

3、测试通过consumer服务远程调用payment服务

在浏览器地址栏里输入http://localhost/consumer/payment/feign/timeout 并且回车调用接口，这时会显示Read timed out executing GET http://CLOUD-PAYMENT-SERVICE/payment/feign/timeout的错误信息，这是因为Feign客户端默认只等待一秒钟，但是服务端处理需要超过1秒钟，导致Feign客户端不想等待了，直接返回报错，为了避免这样的情况，有时候我们需要设置Feign客户端的超时控制。

效果图：

4、设置Feign客户端的超时时间

修改cloud-consumer-feign-order80项目的application.yml文件（因为OpenFeign集成了Ribbon，所以OpenFeign的超时控制也由最底层的Ribbon来进行限制，所以这里是对Ribbon进行配置）

集成示意图：

application.yml文件

server:
  port: 80
eureka:
  client:
    #表示是否将自己注册进Eureka Server里，默认为true
    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