SpringCloud Alibaba入门5之使用OpenFegin调用服务

我们继续在上一章的基础上进行开发

SpringCloud Alibaba入门4之nacos注册中心管理_qinxun2008081的博客-CSDN博客

Feign是一种声明式、模板化的HTTP客户端。使用Feign，可以做到声明式调用。Feign是在RestTemplate和Ribbon的基础上进一步封装，使用RestTemplate实现Http调用，使用Ribbon实现负载均衡。

一、引入依赖

我们在goodds子模块引入OpenFeign的依赖

<!--OpenFeign-->
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

我们把相关的依赖都统一放到common模块下,如下所示:

<?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"><modelVersion>4.0.0</modelVersion><parent><groupId>org.example</groupId><artifactId>myshop</artifactId><version>1.0-SNAPSHOT</version></parent><artifactId>myshop-common</artifactId><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--hibernate-validate--><dependency><groupId>org.hibernate.validator</groupId><artifactId>hibernate-validator</artifactId></dependency><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><!--mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.31</version></dependency><!--JPA--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency></dependencies>
</project>

common模块大概结构如图所示:

我们在数据库连接和JPA相关配置统一放在父项目的目录下

二、Feign远程调用

我们的目的就是在添加商品的时候，通过Feign远程调用库存服务添加对应的库存数量，查询商品的时候同时也要查询库存。

我们按照上一章的办法同时开启商品服务和库存服务。

三、库存(myshop-stock)模块做为服务的提供者

库存实体类:

package com.example.myshop.entity;import lombok.Data;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;
import org.hibernate.annotations.UpdateTimestamp;import javax.persistence.*;
import java.util.Date;/*** @author qx* @date 2023/06/22* @desc 库存实体*/
@Entity
@Table(name = "t_stock")
@DynamicInsert
@DynamicUpdate
@Data
public class Stock {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;/*** 商品ID*/private Long goodsId;/*** 库存量*/private Integer inventory;/*** 创建时间*/@CreationTimestampprivate Date createTime;/*** 更新时间*/@UpdateTimestampprivate Date updateTime;}

库存数据层:

package com.example.myshop.repository;import com.example.myshop.entity.Stock;
import org.springframework.data.jpa.repository.JpaRepository;public interface StockRepository extends JpaRepository<Stock,Long> {Stock findByGoodsId(Long goodsId);}

库存服务层:

package com.example.myshop.service;import com.example.myshop.entity.Stock;
import com.example.myshop.repository.StockRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;/*** @author qx* @date 2023/06/22* @desc 库存服务层*/
@Service
public class StockService {@Autowiredprivate StockRepository stockRepository;/*** 添加库存，返回主键** @param stock 库存对象* @return 主键值*/public Long addStock(Stock stock) {stockRepository.save(stock);return stock.getId();}/*** 根据商品ID获取商品库存数量** @param goodsId 商品ID* @return 库存数量*/public Integer getInventoryById(Long goodsId) {Stock stock = stockRepository.findByGoodsId(goodsId);return stock.getInventory();}}

库存控制层:

package com.example.myshop.controller;import com.example.myshop.entity.Stock;
import com.example.myshop.service.StockService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;/*** @author qx* @date 2023/06/22* @desc 库存控制器*/
@RestController
@RequestMapping("/stock")
public class StockController {@Autowiredprivate StockService stockService;/*** 添加库存** @param stock 库存请求*/@PostMapping("/add")public Long addStock(@RequestBody Stock stock) {return stockService.addStock(stock);}/*** 根据商品ID获取库存数量** @param goodsId 商品ID* @return 库存数量*/@GetMapping("/getinventory/{goodsId}")public Integer getInventoryByGoodsId(@PathVariable Long goodsId) {return stockService.getInventoryById(goodsId);}
}

四、商品(myshop-goods)模块做为服务的消费者

商品实体类:

package com.example.myshop.entity;import lombok.Data;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;
import org.hibernate.annotations.UpdateTimestamp;import javax.persistence.*;
import java.util.Date;/*** @author qx* @date 2023/06/22* @desc 商品实体*/
@Entity
@Table(name = "t_goods")
@DynamicUpdate
@DynamicInsert
@Data
public class Goods {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;/*** 商品名称*/private String goodsName;/*** 价格*/private Double price;/*** 商品介绍*/private String description;/*** 创建时间*/@CreationTimestampprivate Date createTime;/*** 更新时间*/@UpdateTimestampprivate Date updateTime;/*** 状态 0：正常 1：禁用*/@Column(columnDefinition = "tinyint(1) default 0 comment '状态'")private Integer status;/*** 临时存储库存数量 不保存到数据库*/@Transientprivate Integer inventory;}

商品数据层:

package com.example.myshop.repository;import com.example.myshop.entity.Goods;
import org.springframework.data.jpa.repository.JpaRepository;public interface GoodsRepository extends JpaRepository<Goods,Long> {
}

远程调用库存服务的Feign客户端配置

package com.example.myshop.feign;import com.example.myshop.entity.Stock;
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;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;/*** 库存服务feign客户端*/
@FeignClient(value = "stock-service")
public interface StockClientFeign {/*** 调用添加库存的接口*/@PostMapping("/stock/add")Long addStock(@RequestBody Stock stock);/*** 调用根据商品ID获取库存量接口** @param goodsId 商品ID* @return 库存数量*/@GetMapping("/stock/getinventory/{goodsId}")Integer getInventoryByGoodsId(@PathVariable("goodsId") Long goodsId);}

在启动类上加上注解@EnableFeignClientgs扫描Feign客户端

package com.example.myshop;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;/*** @author qx* @date 2023/06/21* @desc*/
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients(basePackages = "com.example.myshop")
public class MyShopGoodsApplication {public static void main(String[] args) {SpringApplication.run(MyShopGoodsApplication.class, args);}
}

商品服务层:

package com.example.myshop.service;import com.example.myshop.common.CommonResult;
import com.example.myshop.entity.Goods;
import com.example.myshop.entity.Stock;
import com.example.myshop.feign.StockClientFeign;
import com.example.myshop.repository.GoodsRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;/*** @author qx* @date 2023/06/22* @desc 商品服务层*/
@Service
public class GoodsService {@Autowiredprivate StockClientFeign stockClientFeign;@Autowiredprivate GoodsRepository goodsRepository;/*** 添加商品** @param goods 商品对象*/public CommonResult addGoods(Goods goods) {goodsRepository.save(goods);// 保存到商品库存表Stock stock = new Stock();stock.setGoodsId(goods.getId());stock.setInventory(goods.getInventory());stockClientFeign.addStock(stock);return CommonResult.success();}/*** 根据ID获取商品数据** @param goodsId 商品ID* @return 商品数据包含库存数量*/public CommonResult<Goods> getGoodsById(Long goodsId) {Goods goods = goodsRepository.findById(goodsId).orElse(null);if (goods != null) {goods.setInventory(stockClientFeign.getInventoryByGoodsId(goodsId));return CommonResult.success(goods);}return CommonResult.fail("数据不存在");}
}

我们使用Feign客户端直接注入就可以了。

商品控制层:

package com.example.myshop.controller;import com.example.myshop.common.CommonResult;
import com.example.myshop.entity.Goods;
import com.example.myshop.service.GoodsService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;/*** @author qx* @date 2023/06/22* @desc 商品控制层*/
@RestController
@RequestMapping("/goods")
public class GoodsController {@Autowiredprivate GoodsService goodsService;/*** 添加商品** @param goods 商品请求实体* @return*/@PostMapping("/add")public CommonResult addGoods(@RequestBody Goods goods) {return goodsService.addGoods(goods);}/*** 根据ID获取商品** @param id 商品ID* @return 商品*/@GetMapping("/{id}")public CommonResult<Goods> getGoodsById(@PathVariable Long id) {return goodsService.getGoodsById(id);}
}