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
     */
    @CreationTimestamp
    private Date createTime;

    /**
     * 更新时间
     */
    @UpdateTimestamp
    private 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 {

    @Autowired
    private 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 {

    @Autowired
    private 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
     */
    @CreationTimestamp
    private Date createTime;

    /**
     * 更新时间
     */
    @UpdateTimestamp
    private 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
     */
    @Transient
    private 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 {


    @Autowired
    private StockClientFeign stockClientFeign;
    @Autowired
    private 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 {

    @Autowired
    private 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);
    }
}