微服务调用方式ribbon

订单服务(调用方) 调用商品服务 获取商品信息
         1、创建order_service项目
         2、使用ribbon. (类似httpClient,URLConnection) 
            启动类增加注解
              @Bean
              @LoadBalanced
              public RestTemplate restTemplate() {
                   return new RestTemplate();
              }

package net.xdclass.order_service;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class OrderServiceApplication {

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

    @Bean
    @LoadBalanced//指定负载均衡的策略
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

　　 3、开发下单接口

controller:

package net.xdclass.order_service.controller;

import net.xdclass.order_service.service.ProductOrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("api/v1/order")
public class OrderController {


    @Autowired
    private ProductOrderService productOrderService;

    /**
     *
     * @param userId
     * @param productId
     * @return
     */
    @RequestMapping("save")
    public Object save(
            @RequestParam("user_id")int userId,
            @RequestParam("product_id") int productId){

        return productOrderService.save(userId, productId);
    }

}

service:主要是service业务层，如何调用 商品服务 的接口呢？

先写个接口

package net.xdclass.order_service.service;

import net.xdclass.order_service.domain.ProductOrder;

/**
 * 订单业务类
 */
public interface ProductOrderService {


    /**
     * 下单接口
     * @param userId
     * @param productId
     * @return
     */
     ProductOrder save(int userId, int productId);


}

调用方式一：service

使用RestTemplate类的方法，指定服务名称product-service的接口即可

Spring RestTemplate中几种常见的请求方式：https://blog.csdn.net/u012702547/article/details/77917939/

package net.xdclass.order_service.service.impl;

import net.xdclass.order_service.domain.ProductOrder;
import net.xdclass.order_service.service.ProductOrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import sun.net.www.URLConnection;
import sun.net.www.http.HttpClient;

import java.util.Date;
import java.util.Map;
import java.util.UUID;

@Service
public class ProductOrderServiceImpl implements ProductOrderService {


    @Autowired
    private RestTemplate restTemplate;

    @Override
    public ProductOrder save(int userId, int productId) {
        /**
         * 调用product-service的接口
         */
        Map<String,Object> productMap = restTemplate.getForObject("http://product-service/api/v1/product/find?id="+productId, Map.class);

        ProductOrder productOrder = new ProductOrder();
        productOrder.setCreateTime(new Date());
        productOrder.setUserId(userId);
        productOrder.setTradeNo(UUID.randomUUID().toString());
        productOrder.setProductName(productMap.get("name").toString());
        productOrder.setPrice(Integer.parseInt(productMap.get("price").toString()));
        return productOrder;
    }
}

调用方式二：sevice

1.注入LoadBalancerClient对象，可以从这个对象中获取服务名称，端口号等等信息

2.然后用这个对象构造一个url

3.再使用RestTemplate类的方法发送请求即可

　　注意：%s表示后的参数的，第一个表示第一个参数，第二个表示第二个参数...

package net.xdclass.order_service.service.impl;

import net.xdclass.order_service.domain.ProductOrder;
import net.xdclass.order_service.service.ProductOrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import sun.net.www.URLConnection;
import sun.net.www.http.HttpClient;

import java.util.Date;
import java.util.Map;
import java.util.UUID;

@Service
public class ProductOrderServiceImpl implements ProductOrderService {


    @Autowired
    private RestTemplate restTemplate;
    //
//    @Autowired
    private LoadBalancerClient loadBalancer;


    @Override
    public ProductOrder save(int userId, int productId) {


        //调用方式二
        ServiceInstance instance = loadBalancer.choose("product-service");
        String url = String.format("http://%s:%s/api/v1/product/find?id="+productId, instance.getHost(),instance.getPort());
        RestTemplate restTemplate = new RestTemplate();
        Map<String,Object> productMap = restTemplate.getForObject(url, Map.class);


        ProductOrder productOrder = new ProductOrder();
        productOrder.setCreateTime(new Date());
        productOrder.setUserId(userId);
        productOrder.setTradeNo(UUID.randomUUID().toString());
        productOrder.setProductName(productMap.get("name").toString());
        productOrder.setPrice(Integer.parseInt(productMap.get("price").toString()));
        return productOrder;
    }
}