SpringCloud - Hystrix（五）

Feign-Hystrix 使用

1. order 配置開關 feign: hystrix: enabled: true

2. product 注解綁定 @FeignClient(name = "product", fallback = ProductClient.ProductClientFallback.class)

（注意ProductClientFallback類加@Component注解）

3. order 注意包掃描 @ComponentScan(basePackages = "com.imooc")

Product 微服務項目

package com.imooc.product.client;

import com.imooc.product.common.DecreaseStockInput;
import com.imooc.product.common.ProductInfoOutput;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import java.util.List;

@FeignClient(name = "product", fallback = ProductClient.ProductClientFallback.class)
public interface ProductClient {

    @PostMapping("/product/listForOrder")
    List<ProductInfoOutput> listForOrder(@RequestBody List<String> productIdList);

    @PostMapping("/product/decreaseStock")
    void decreaseStock(@RequestBody List<DecreaseStockInput> decreaseStockInputList);

    @Component
    static class ProductClientFallback implements ProductClient {

        @Override
        public List<ProductInfoOutput> listForOrder(List<String> productIdList) {
            return null;
        }

        @Override
        public void decreaseStock(List<DecreaseStockInput> decreaseStockInputList) {

        }
    }
}      

Order 微服務項目

spring:
  application:
    name: order
  cloud:
    config:
      discovery:
        enabled: true
        service-id: CONFIG
      profile: test
    stream:
      bindings:
        myMessage:
          group: order
          content-type: application/json
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/

hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 1000
    getProductInfoList:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 3000
feign:
  hystrix:
    enabled: true      

package com.imooc.order;

import org.springframework.boot.SpringApplication;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;

@EnableFeignClients(basePackages = "com.imooc.product.client")
//@SpringBootApplication
//@EnableDiscoveryClient
//@EnableCircuitBreaker
@SpringCloudApplication
@ComponentScan(basePackages = "com.imooc")
public class OrderApplication {

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

• 這裡需要包掃描是因為雖然服務降級處理方法代碼是寫在 product 裡的，但是 product 打包後會被 order 識别到，這是就需要包掃描找到它才可以打通。

package com.imooc.order.service.impl;

import com.imooc.order.dataobject.OrderDetail;
import com.imooc.order.dataobject.OrderMaster;
import com.imooc.order.dto.OrderDTO;
import com.imooc.order.enums.OrderStatusEnum;
import com.imooc.order.enums.PayStatusEnum;
import com.imooc.order.enums.ResultEnum;
import com.imooc.order.exception.OrderException;
import com.imooc.order.repository.OrderDetailRepository;
import com.imooc.order.repository.OrderMasterRepository;
import com.imooc.order.service.OrderService;
import com.imooc.order.utils.KeyUtil;
import com.imooc.product.client.ProductClient;
import com.imooc.product.common.DecreaseStockInput;
import com.imooc.product.common.ProductInfoOutput;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;
import javax.transaction.Transactional;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.List;
import java.util.Optional;
import java.util.stream.Collectors;

@Service
public class OrderServiceImpl implements OrderService {

    @Autowired
    private OrderDetailRepository orderDetailRepository;

    @Autowired
    private OrderMasterRepository orderMasterRepository;

    @Autowired
    private ProductClient productClient;

    @Override
    @Transactional
    public OrderDTO create(OrderDTO orderDTO) {
        String orderId = KeyUtil.genUniqueKey();

        // 查詢商品資訊(調用商品服務)
        List<String> productIdList = orderDTO.getOrderDetailList().stream()
                .map(OrderDetail::getProductId)
                .collect(Collectors.toList());
        // 斷點這裡看 productInfoList 是否為 null 就知道服務是否降級成功：null 則成功，否則不成功
        List<ProductInfoOutput> productInfoList = productClient.listForOrder(productIdList);

        // 計算總價
        //...

        //扣庫存(調用商品服務)
        //...
    }
}