以电商项目为线索，快速掌握 JDK17 + springboot3 + springcloud Alibaba 专栏源码

package com.example.server.service.impl; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import com.example.domain.Order; import com.example.domain.Product; import com.example.server.feign.IProductFeignService; import com.example.server.mapper.OrderMapper; import com.example.server.service.OrderService; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.cloud.client.ServiceInstance; import org.springframework.cloud.client.discovery.DiscoveryClient; import org.springframework.http.HttpEntity; import org.springframework.http.HttpHeaders; import org.springframework.http.MediaType; import org.springframework.stereotype.Service; import org.springframework.web.client.RestTemplate; import java.util.HashMap; import java.util.List; import java.util.Random; @Slf4j @Service public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService { // @Autowired // private RestTemplate restTemplate; @Autowired private DiscoveryClient discoveryClient; @Autowired private IProductFeignService productFeignService; @Override public Order createOrder(Long pid, Long uid) { Order order = new Order(); //商品 //方案1：通过restTemplate方式 //String url = "http://localhost:8081/products/" + pid; //Product product = restTemplate.getForObject(url, Product.class); //方案2：使用注册中心api方式-discoveryClient //List<ServiceInstance> instances = discoveryClient.getInstances("product-service"); //ServiceInstance instance = instances.get(0); //当前只有一个 //String host = instance.getHost(); //int port = instance.getPort(); //String url = "http://" + host + ":" + port + "/products/" + pid; //Product product = restTemplate.getForObject(url, Product.class); //方案3：使用注册中心api方式-discoveryClient--带负载均衡 // List<ServiceInstance> instances = discoveryClient.getInstances("product-service"); // int index = new Random().nextInt(instances.size()); // ServiceInstance instance = instances.get(index); // String host = instance.getHost(); // int port = instance.getPort(); // String url = "http://" + host + ":" + port + "/products/" + pid; // System.out.println("从nacos中获取的url地址：" + url); // Product product = restTemplate.getForObject(url, Product.class); //方案4：使用服务名称来发起请求，Ribbon将自动选择一个可用的实例 // String productServiceUrl = "http://product-service/products/" + pid; // // 使用 RestTemplate 发起HTTP请求 // Product product = restTemplate.getForObject(productServiceUrl, Product.class); log.info("2>>请求进入OrderServiceImpl.createOrder:准备进行下订单-查询商品信息前"); //方案5：使用Feign接口的方式--负载均衡 Product product = productFeignService.get(pid); log.info("4>>请求进入OrderServiceImpl.createOrder:准备进行下订单-查询商品信息后"); //商品 order.setPid(pid); order.setProductPrice(product.getPrice()); order.setProductName(product.getName()); //用户相关 order.setUid(uid); order.setUsername("sadw"); order.setNumber(100); //getBaseMapper().insert(order) super.save(order); log.info("5>>请求进入OrderServiceImpl.createOrder:下订单完成"); return order; } }