go语言web开发系列之十六:gin框架中通过gorm使用事务
一,演示项目的相关信息
1,地址:
https://github.com/liuhongdi/digv16
2,功能:以下订单为例,演示了在gorm中启用事务
3, 项目结构:如图:
说明:刘宏缔的go森林是一个专注golang的博客,
地址:https://blog.csdn.net/weixin_43881017
说明:作者:刘宏缔 邮箱: 371125307@qq.com
二,数据库及sql
1,数据表:
2,建表sql:
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CREATE TABLE `m_goods` (
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`goodsId` bigint unsigned NOT NULL AUTO_INCREMENT COMMENT '商品id',
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`goodsName` varchar(200) NOT NULL DEFAULT '' COMMENT '商品名称',
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`stock` int unsigned NOT NULL DEFAULT '0' COMMENT '库存数量',
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PRIMARY KEY (`goodsId`)
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) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='商品表'
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CREATE TABLE `m_order` (
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`orderId` bigint unsigned NOT NULL AUTO_INCREMENT COMMENT '订单id',
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`userId` bigint unsigned NOT NULL DEFAULT '0' COMMENT '用户id',
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`salePrice` decimal(10,0) NOT NULL DEFAULT '0' COMMENT '订单金额',
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PRIMARY KEY (`orderId`),
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KEY `userId` (`userId`)
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) ENGINE=InnoDB AUTO_INCREMENT=0 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='订单表'
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CREATE TABLE `m_order_goods` (
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`ogId` bigint unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
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`orderId` bigint unsigned NOT NULL COMMENT '订单id',
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`goodsId` bigint unsigned NOT NULL COMMENT '商品id',
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`buyNum` int unsigned NOT NULL COMMENT '购买数量',
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PRIMARY KEY (`ogId`),
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UNIQUE KEY `orderId_2` (`orderId`,`goodsId`)
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) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci COMMENT='订单商品表'
3,插入一条演示数据:
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INSERT INTO `m_goods` (`goodsId`, `goodsName`, `stock`) VALUES
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(1, '施丹兰蜂蜜牛奶手工皂', 10);
三,go代码说明
1,controller/orderController.go
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package controller
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import (
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"fmt"
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"github.com/gin-gonic/gin"
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"github.com/liuhongdi/digv16/global"
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"github.com/liuhongdi/digv16/service"
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)
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type OrderController struct{}
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//result:= global.NewResult(c)
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func NewOrderController() OrderController {
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return OrderController{}
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}
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//新加一个订单
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func (o *OrderController) AddOne(c *gin.Context) {
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result := global.NewResult(c)
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goodsId:=1;
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buyNum:=11;
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orderOne,err := service.AddOneOrder(int64(goodsId),buyNum);
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if err != nil {
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result.Error(404,"数据处理错误")
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} else {
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result.Success(&orderOne);
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}
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return
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}
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-
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//新加一个订单,使用tx
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func (o *OrderController) AddOneTx(c *gin.Context) {
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result := global.NewResult(c)
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goodsId:=1;
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buyNum:=11;
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orderOne,err := service.AddOneOrderTx(int64(goodsId),buyNum);
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fmt.Println("orderOne:");
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fmt.Println(orderOne);
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fmt.Println(":end:");
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//if ()
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if (orderOne == nil || err != nil) {
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result.Error(20001,"数据处理错误")
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} else {
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result.Success(&orderOne);
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}
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return
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}
2,service/order.go
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package service
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import (
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"github.com/liuhongdi/digv16/dao"
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"github.com/liuhongdi/digv16/model"
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)
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//新加一个订单
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func AddOneOrder(goodsId int64,buyNum int) (*model.Order, error) {
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return dao.AddOneOrder(goodsId,buyNum)
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}
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//新加一个订单,使用tx
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func AddOneOrderTx(goodsId int64,buyNum int) (*model.Order, error) {
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return dao.AddOneOrderTx(goodsId,buyNum)
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}
3,dao/order.go
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package dao
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import (
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"errors"
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"fmt"
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"github.com/liuhongdi/digv16/global"
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"github.com/liuhongdi/digv16/model"
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"gorm.io/gorm"
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)
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//添加一个订单
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func AddOneOrder(goodsId int64,buyNum int) (*model.Order, error) {
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//添加order
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order := model.Order{UserId: 1, SalePrice: "20.00"}
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resultCO := global.DBLink.Create(&order) // 通过数据的指针来创建
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if (resultCO.Error != nil) {
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return nil,resultCO.Error
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}
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//减库存
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result := global.DBLink.Debug().Table("m_goods").Where("goodsId = ? and stock >= ?", goodsId,buyNum).Update("stock", gorm.Expr("stock - ?", buyNum))
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if (result.Error != nil) {
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return nil,result.Error
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}
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if (result.RowsAffected <= 0){
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return nil,errors.New("减库存失败")
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}
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//添加订单商品
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orderId := order.OrderId;
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orderGoods := model.OrderGoods{OrderId:orderId,GoodsId:goodsId,BuyNum:buyNum}
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resultCOG := global.DBLink.Create(&orderGoods) // 通过数据的指针来创建
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if (resultCOG.Error != nil) {
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return nil,resultCOG.Error
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}
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//return
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return &order,nil
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}
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-
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//添加一个订单
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func AddOneOrderTx(goodsId int64,buyNum int) (*model.Order, error) {
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// 事务开始后,需要使用 tx 处理数据
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tx := global.DBLink.Begin()
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defer func() {
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if r := recover(); r != nil {
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fmt.Println("this is in defer recover")
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tx.Rollback()
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}
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}()
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if err := tx.Error; err != nil {
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return nil,err
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}
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//添加order
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order := model.Order{UserId: 1, SalePrice: "20.00"}
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resultCO := tx.Debug().Create(&order) // 通过数据的指针来创建
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if (resultCO.Error != nil) {
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tx.Rollback()
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return nil,resultCO.Error
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}
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/*
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var z int = 0
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var i int = 100 / z
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fmt.Println("i:%i",i)
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*/
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//减库存
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result := tx.Debug().Table("m_goods").Where("goodsId = ? and stock >= ?", goodsId,buyNum).Update("stock", gorm.Expr("stock - ?", buyNum))
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if (result.Error != nil) {
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tx.Rollback()
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return nil,result.Error
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}
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if (result.RowsAffected <= 0){
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tx.Rollback()
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fmt.Println("减库存失败")
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return nil,errors.New("减库存失败")
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}
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//添加订单商品
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orderId := order.OrderId;
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orderGoods := model.OrderGoods{OrderId:orderId,GoodsId:goodsId,BuyNum:buyNum}
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resultCOG := tx.Debug().Create(&orderGoods) // 通过数据的指针来创建
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if (resultCOG.Error != nil) {
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tx.Rollback()
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return nil,resultCOG.Error
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}
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//commit
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fmt.Println("begin commit")
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errCM := tx.Commit().Error
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if (errCM != nil) {
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fmt.Println("begin return1")
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tx.Rollback()
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return nil,errCM
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}else {
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fmt.Println("begin return2")
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return &order,nil
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}
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}
4,model/goods.go
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package model
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type Goods struct {
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GoodsId int64 `gorm:"column:goodsId",json:"goodsId"` // 自增
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GoodsName string `gorm:"column:goodsName",json:"goodsName"` // 用户id
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Stock int `gorm:"column:stock",json:"stock"` // 售价
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}
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func (Goods) TableName() string {
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return "m_goods"
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}
5,model/order.go
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package model
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type Order struct {
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OrderId int64 `gorm:"primaryKey;autoIncrement;column:orderId",json:"orderid"` // 自增
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UserId int64 `gorm:"column:userId",json:"userid"` // 用户id
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SalePrice string `gorm:"column:salePrice",json:"saleprice"` // 售价
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}
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func (Order) TableName() string {
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return "m_order"
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}
6,router/router.go
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package router
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import (
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"github.com/gin-gonic/gin"
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"github.com/liuhongdi/digv16/controller"
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"github.com/liuhongdi/digv16/global"
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"log"
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"runtime/debug"
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)
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func Router() *gin.Engine {
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router := gin.Default()
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//处理异常
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router.NoRoute(HandleNotFound)
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router.NoMethod(HandleNotFound)
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router.Use(Recover)
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// 路径映射
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goodsc:=controller.NewGoodsController()
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router.GET("/goods/getone/:id", goodsc.GetOne);
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//router.GET("/article/list", articlec.GetList);
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orderc:=controller.NewOrderController()
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router.GET("/order/addone", orderc.AddOne);
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router.GET("/order/addonetx", orderc.AddOneTx);
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return router
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}
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func HandleNotFound(c *gin.Context) {
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global.NewResult(c).Error(404,"资源未找到")
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return
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}
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func Recover(c *gin.Context) {
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defer func() {
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if r := recover(); r != nil {
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//打印错误堆栈信息
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log.Printf("panic: %v\n", r)
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debug.PrintStack()
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global.NewResult(c).Error(500,"服务器内部错误")
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}
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}()
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//加载完 defer recover,继续后续接口调用
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c.Next()
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}
7,其他相关代码可访问github查看
四,测试效果
1,测试除0错:
访问:
http://127.0.0.1:8080/order/addonetx
返回:
2,测试扣减库存出错
把dao/order.go中,
AddOneOrderTx方法中的除0错代码注释掉
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/*
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var z int = 0
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var i int = 100 / z
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fmt.Println("i:%i",i)
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*/
再次执行:访问:
http://127.0.0.1:8080/order/addonetx
可以从控制台看到输出的提示:
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2021/01/13 13:32:25 /data/liuhongdi/digv16/dao/order.go:69
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[2.219ms] [rows:0] UPDATE `m_goods` SET `stock`=stock - 11 WHERE goodsId = 1 and stock >= 11
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减库存失败
3,测试正常执行事务成功
把controller/orderController.go中,
AddOneTx方法,把buyNum的值改为9
buyNum:=9
再次执行:
http://127.0.0.1:8080/order/addonetx
返回:
事务执行已成功
五,使用的库的版本:
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module github.com/liuhongdi/digv16
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go 1.15
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require (
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github.com/gin-gonic/gin v1.6.3
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github.com/jinzhu/gorm v1.9.16 // indirect
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gorm.io/driver/mysql v1.0.1
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gorm.io/gorm v1.20.6
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)
posted on 2021-01-22 11:19 ExplorerMan 阅读(960) 评论(0) 编辑 收藏 举报