Mybatis-注解方式的使用

1、导入依赖

        <dependency>
            <groupId>org.mybatis.spring.bootgroupId>
            <artifactId>mybatis-spring-boot-starterartifactId>
            <version>1.3.1version>
        dependency>

2、实体类

package com.arivan.seckill.entity;

public class Goods {

    private Long id;

    private String goodsName;

    private String goodsTitle;

    private String goodsImg;

    private String goodsDetail;

    private Double goodsPrice;

    private Integer goodsStock;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getGoodsName() {
        return goodsName;
    }

    public void setGoodsName(String goodsName) {
        this.goodsName = goodsName;
    }

    public String getGoodsTitle() {
        return goodsTitle;
    }

    public void setGoodsTitle(String goodsTitle) {
        this.goodsTitle = goodsTitle;
    }

    public String getGoodsImg() {
        return goodsImg;
    }

    public void setGoodsImg(String goodsImg) {
        this.goodsImg = goodsImg;
    }

    public String getGoodsDetail() {
        return goodsDetail;
    }

    public void setGoodsDetail(String goodsDetail) {
        this.goodsDetail = goodsDetail;
    }

    public Double getGoodsPrice() {
        return goodsPrice;
    }

    public void setGoodsPrice(Double goodsPrice) {
        this.goodsPrice = goodsPrice;
    }

    public Integer getGoodsStock() {
        return goodsStock;
    }

    public void setGoodsStock(Integer goodsStock) {
        this.goodsStock = goodsStock;
    }

    @Override
    public String toString() {
        return "Goods{" +
                "id=" + id +
                ", goodsName='" + goodsName + '\'' +
                ", goodsTitle='" + goodsTitle + '\'' +
                ", goodsImg='" + goodsImg + '\'' +
                ", goodsDetail='" + goodsDetail + '\'' +
                ", goodsPrice=" + goodsPrice +
                ", goodsStock=" + goodsStock +
                '}';
    }
}

3、添加配置文件，配置数据库信息

spring:
  datasource:
    #   数据源基本配置
    username: root
    password: password
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://47.98.107.240:3306/miaosha?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&useSSL=false
    

4、添加接口，写sql语句，需要使用@Mapper和@Repository注解

package com.arivan.seckill.dao;


import com.arivan.seckill.entity.Goods;
import com.arivan.seckill.entity.MiaoshaGoods;
import com.arivan.seckill.vo.GoodsVo;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
@Mapper
public interface GoodsDao {

    @Select("select g.*,mg.miaosha_price,mg.stock_count,mg.start_date,mg.end_date from miaosha_goods mg left join goods g on mg.goods_id = g.id")
    List<GoodsVo> listGoodsVo();

    @Select("select g.*,mg.miaosha_price,mg.stock_count,mg.start_date,mg.end_date from miaosha_goods mg left join goods g on mg.goods_id = g.id where g.id = #{goodsId}")
    GoodsVo getGoodsVoByGoodsId(@Param("goodsId") long goodsId);

    @Update("update miaosha_goods set stock_count = stock_count - 1 where goods_id = #{goodsId} and stock_count > 0")
    int reduceStock(MiaoshaGoods g);
}