技术标签： 微服务
数据库事务的基本概念（ACID）
原子性（Atomicity）：操作这些指令时，要么全部执行成功，要么全部不执行。只要其中一个指令执行失败，所有的指令都执行失败，数据进行回滚，回到执行指令前的数据状态。要么执行，要么不执行
一致性（Consistency）：事务的执行使数据从一个状态转换为另一个状态，数据库的完整性约束没有被破坏。能量守恒，总量不变
隔离性（Isolation）：隔离性是当多个用户并发访问数据库时，比如操作同一张表时，数据库为每一个用户开启的事务，不能被其他事务的操作所干扰，多个并发事务之间要相互隔离。信息彼此独立，互不干扰
持久性（Durability）：当事务正确完成后，它对于数据的改变是永久性的。不会轻易丢失
什么是分布式事务
指一次大的操作由不同的小操作组成的，这些小的操作分布在不同的服务器上，分布式事务需要保证这些小操作要么全部成功，要么全部失败。从本质上来说，分布式事务就是为了保证不同数据库的数据一致性。
为什么要使用分布式事务
在微服务独立数据源的思想，每一个微服务都有一个或者多个数据源，虽然单机单库事务已经非常成熟，但是由于网路延迟和不可靠的客观因素，分布式事务到现在也还没有成熟的方案，对于中大型网站，特别是涉及到交易的网站，一旦将服务拆分微服务，分布式事务一定是绕不开的一个组件，通常解决分布式事务问题。
seata 分布式事务
Seata是阿里开源的一款开源的分布式事务解决方案，致力于提供高性能和简单易用的分布式事务服务。
Seata目标打造一站式的分布事务的解决方案，最终会提供四种事务模式：
AT 模式、TCC 模式、Saga 模式、XA 模式
目前使用的流行度情况是：AT > TCC > Saga。因此，我们在学习Seata的时候，可以花更多精力在AT模式上，最好搞懂背后的实现原理，毕竟分布式事务涉及到数据的正确性，出问题需要快速排查定位并解决。
下载方式
Windows平台安装包下载
可以从https://github.com/seata/seata/releases下载seata-server-$version.zip包。
Windows下载解压后（.zip），直接点击bin/seata-server.bat就可以了。
1、创建相关测试数据库和表。
# 订单数据库信息 seata_order
DROP DATABASE IF EXISTS seata_order;
CREATE DATABASE seata_order;
DROP TABLE IF EXISTS seata_order.p_order;
CREATE TABLE seata_order.p_order
(
id INT(11) NOT NULL AUTO_INCREMENT,
user_id INT(11) DEFAULT NULL,
product_id INT(11) DEFAULT NULL,
amount INT(11) DEFAULT NULL,
total_price DOUBLE DEFAULT NULL,
status VARCHAR(100) DEFAULT NULL,
add_time DATETIME DEFAULT CURRENT_TIMESTAMP,
last_update_time DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
DROP TABLE IF EXISTS seata_order.undo_log;
CREATE TABLE seata_order.undo_log
(
id BIGINT(20) NOT NULL AUTO_INCREMENT,
branch_id BIGINT(20) NOT NULL,
xid VARCHAR(100) NOT NULL,
context VARCHAR(128) NOT NULL,
rollback_info LONGBLOB NOT NULL,
log_status INT(11) NOT NULL,
log_created DATETIME NOT NULL,
log_modified DATETIME NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY ux_undo_log (xid, branch_id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
# 产品数据库信息 seata_product
DROP DATABASE IF EXISTS seata_product;
CREATE DATABASE seata_product;
DROP TABLE IF EXISTS seata_product.product;
CREATE TABLE seata_product.product
(
id INT(11) NOT NULL AUTO_INCREMENT,
price DOUBLE DEFAULT NULL,
stock INT(11) DEFAULT NULL,
last_update_time DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
DROP TABLE IF EXISTS seata_product.undo_log;
CREATE TABLE seata_product.undo_log
(
id BIGINT(20) NOT NULL AUTO_INCREMENT,
branch_id BIGINT(20) NOT NULL,
xid VARCHAR(100) NOT NULL,
context VARCHAR(128) NOT NULL,
rollback_info LONGBLOB NOT NULL,
log_status INT(11) NOT NULL,
log_created DATETIME NOT NULL,
log_modified DATETIME NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY ux_undo_log (xid, branch_id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
INSERT INTO seata_product.product (id, price, stock)
VALUES (1, 10, 20);
# 账户数据库信息 seata_account
DROP DATABASE IF EXISTS seata_account;
CREATE DATABASE seata_account;
DROP TABLE IF EXISTS seata_account.account;
CREATE TABLE seata_account.account
(
id INT(11) NOT NULL AUTO_INCREMENT,
balance DOUBLE DEFAULT NULL,
last_update_time DATETIME DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
DROP TABLE IF EXISTS seata_account.undo_log;
CREATE TABLE seata_account.undo_log
(
id BIGINT(20) NOT NULL AUTO_INCREMENT,
branch_id BIGINT(20) NOT NULL,
xid VARCHAR(100) NOT NULL,
context VARCHAR(128) NOT NULL,
rollback_info LONGBLOB NOT NULL,
log_status INT(11) NOT NULL,
log_created DATETIME NOT NULL,
log_modified DATETIME NOT NULL,
PRIMARY KEY (id),
UNIQUE KEY ux_undo_log (xid, branch_id)
) ENGINE = InnoDB
AUTO_INCREMENT = 1
DEFAULT CHARSET = utf8mb4;
INSERT INTO seata_account.account (id, balance)
VALUES (1, 50);
其中，每个库中的undo_log表，是Seata AT模式必须创建的表，主要用于分支事务的回滚。
另外，考虑到测试方便，我们插入了一条id = 1的account记录，和一条id = 1的product记录。
2、引入seata配置
<!-- SpringBoot Seata -->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<!--<version>2.2.2.RELEASE</version>-->
</dependency>3、服务配置文件 DataSource下面引入所有用到的数据源
# spring配置
spring:
redis:
host: localhost
port: 6379
password:
datasource:
druid:
stat-view-servlet:
enabled: true
loginUsername: admin
loginPassword: 123456
dynamic:
druid:
initial-size: 5
min-idle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,wall,slf4j
connectionProperties: druid.stat.mergeSql\=true;druid.stat.slowSqlMillis\=5000
datasource:
# 主库数据源
master:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/ry-cloud?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
username: root
password: password
# seata_order数据源
order:
username: root
password: password
url: jdbc:mysql://localhost:3306/seata_order?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
driver-class-name: com.mysql.cj.jdbc.Driver
# seata_account数据源
account:
username: root
password: password
url: jdbc:mysql://localhost:3306/seata_account?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
driver-class-name: com.mysql.cj.jdbc.Driver
# seata_product数据源
product:
username: root
password: password
url: jdbc:mysql://localhost:3306/seata_product?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=true&serverTimezone=GMT%2B8
driver-class-name: com.mysql.cj.jdbc.Driver
seata: true #开启seata代理，开启后默认每个数据源都代理，如果某个不需要代理可单独关闭
# seata配置
seata:
enabled: true
# Seata 应用编号，默认为 ${spring.application.name}
application-id: ${spring.application.name}
# Seata 事务组编号，用于 TC 集群名
tx-service-group: ${spring.application.name}-group
# 关闭自动代理
enable-auto-data-source-proxy: false
# 服务配置项
service:
# 虚拟组和分组的映射
vgroup-mapping:
ruoyi-system-group: default
# 分组和 Seata 服务的映射
grouplist:
default: 127.0.0.1:8091
config:
type: file
registry:
type: file
# mybatis配置
mybatis:
# 搜索指定包别名
typeAliasesPackage: com.ruoyi.system
# 配置mapper的扫描，找到所有的mapper.xml映射文件
mapperLocations: classpath:mapper/**/*.xml
# swagger配置
swagger:
title: 系统模块接口文档
license: Powered By ruoyi
licenseUrl: https://ruoyi.vipAccount.java
package com.ruoyi.system.domain;
import java.util.Date;
public class Account
{
private Long id;
/**
* 余额
*/
private Double balance;
private Date lastUpdateTime;
public Long getId()
{
return id;
}
public void setId(Long id)
{
this.id = id;
}
public Double getBalance()
{
return balance;
}
public void setBalance(Double balance)
{
this.balance = balance;
}
public Date getLastUpdateTime()
{
return lastUpdateTime;
}
public void setLastUpdateTime(Date lastUpdateTime)
{
this.lastUpdateTime = lastUpdateTime;
}
}
Order.java
package com.ruoyi.system.domain;
public class Order
{
private Integer id;
/**
* 用户ID
*/
private Long userId;
/**
* 商品ID
*/
private Long productId;
/**
* 订单状态
*/
private int status;
/**
* 数量
*/
private Integer amount;
/**
* 总金额
*/
private Double totalPrice;
public Order()
{
}
public Order(Long userId, Long productId, int status, Integer amount)
{
this.userId = userId;
this.productId = productId;
this.status = status;
this.amount = amount;
}
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
public Long getUserId()
{
return userId;
}
public void setUserId(Long userId)
{
this.userId = userId;
}
public Long getProductId()
{
return productId;
}
public void setProductId(Long productId)
{
this.productId = productId;
}
public int getStatus()
{
return status;
}
public void setStatus(int status)
{
this.status = status;
}
public Integer getAmount()
{
return amount;
}
public void setAmount(Integer amount)
{
this.amount = amount;
}
public Double getTotalPrice()
{
return totalPrice;
}
public void setTotalPrice(Double totalPrice)
{
this.totalPrice = totalPrice;
}
}
Product.java
package com.ruoyi.system.domain;
import java.util.Date;
public class Product
{
private Integer id;
/**
* 价格
*/
private Double price;
/**
* 库存
*/
private Integer stock;
private Date lastUpdateTime;
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
public Double getPrice()
{
return price;
}
public void setPrice(Double price)
{
this.price = price;
}
public Integer getStock()
{
return stock;
}
public void setStock(Integer stock)
{
this.stock = stock;
}
public Date getLastUpdateTime()
{
return lastUpdateTime;
}
public void setLastUpdateTime(Date lastUpdateTime)
{
this.lastUpdateTime = lastUpdateTime;
}
}
Dto
PlaceOrderRequest.java
package com.ruoyi.system.domain.dto;
public class PlaceOrderRequest
{
private Long userId;
private Long productId;
private Integer amount;
public PlaceOrderRequest()
{
}
public PlaceOrderRequest(Long userId, Long productId, Integer amount)
{
this.userId = userId;
this.productId = productId;
this.amount = amount;
}
public Long getUserId()
{
return userId;
}
public void setUserId(Long userId)
{
this.userId = userId;
}
public Long getProductId()
{
return productId;
}
public void setProductId(Long productId)
{
this.productId = productId;
}
public Integer getAmount()
{
return amount;
}
public void setAmount(Integer amount)
{
this.amount = amount;
}
}
ReduceBalanceRequest.java
package com.ruoyi.system.domain.dto;
public class ReduceBalanceRequest
{
private Long userId;
private Integer price;
public Long getUserId()
{
return userId;
}
public void setUserId(Long userId)
{
this.userId = userId;
}
public Integer getPrice()
{
return price;
}
public void setPrice(Integer price)
{
this.price = price;
}
}
ReduceStockRequest.java
package com.ruoyi.system.domain.dto;
public class ReduceStockRequest
{
private Long productId;
private Integer amount;
public Long getProductId()
{
return productId;
}
public void setProductId(Long productId)
{
this.productId = productId;
}
public Integer getAmount()
{
return amount;
}
public void setAmount(Integer amount)
{
this.amount = amount;
}
}
Mapper
AccountMapper.java
package com.ruoyi.system.mapper;
import com.ruoyi.system.domain.Account;
public interface AccountMapper
{
public Account selectById(Long userId);
public void updateById(Account account);
}
OrderMapper.java
package com.ruoyi.system.mapper;
import com.ruoyi.system.domain.Order;
public interface OrderMapper
{
public void insert(Order order);
public void updateById(Order order);
}
ProductMapper.java
package com.ruoyi.system.mapper;
import com.ruoyi.system.domain.Product;
public interface ProductMapper
{
public Product selectById(Long productId);
public void updateById(Product product);
}
Service
AccountService.java
package com.ruoyi.system.service;
public interface AccountService
{
/**
* 账户扣减
* @param userId 用户 ID
* @param price 扣减金额
*/
void reduceBalance(Long userId, Double price);
}
OrderService.java
package com.ruoyi.system.service;
import com.ruoyi.system.domain.dto.PlaceOrderRequest;
public interface OrderService
{
/**
* 下单
*
* @param placeOrderRequest 订单请求参数
*/
void placeOrder(PlaceOrderRequest placeOrderRequest);
}
ProductService.java
package com.ruoyi.system.service;
public interface ProductService
{
/**
* 扣减库存
*
* @param productId 商品 ID
* @param amount 扣减数量
* @return 商品总价
*/
Double reduceStock(Long productId, Integer amount);
}
AccountService.java
package com.ruoyi.system.service.impl;
import javax.annotation.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.ruoyi.system.domain.Account;
import com.ruoyi.system.mapper.AccountMapper;
import com.ruoyi.system.service.AccountService;
import io.seata.core.context.RootContext;
@Service
public class AccountServiceImpl implements AccountService
{
private static final Logger log = LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
private AccountMapper accountMapper;
/**
* 事务传播特性设置为 REQUIRES_NEW 开启新的事务 重要！！！！一定要使用REQUIRES_NEW
*/
@DS("account")
@Override
@Transactional(propagation = Propagation.REQUIRES_NEW)
public void reduceBalance(Long userId, Double price)
{
log.info("=============ACCOUNT START=================");
log.info("当前 XID: {}", RootContext.getXID());
Account account = accountMapper.selectById(userId);
Double balance = account.getBalance();
log.info("下单用户{}余额为 {},商品总价为{}", userId, balance, price);
if (balance < price)
{
log.warn("用户 {} 余额不足，当前余额:{}", userId, balance);
throw new RuntimeException("余额不足");
}
log.info("开始扣减用户 {} 余额", userId);
double currentBalance = account.getBalance() - price;
account.setBalance(currentBalance);
accountMapper.updateById(account);
log.info("扣减用户 {} 余额成功,扣减后用户账户余额为{}", userId, currentBalance);
log.info("=============ACCOUNT END=================");
}
}
OrderService.java
package com.ruoyi.system.service.impl;
import javax.annotation.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.ruoyi.system.domain.Order;
import com.ruoyi.system.domain.dto.PlaceOrderRequest;
import com.ruoyi.system.mapper.OrderMapper;
import com.ruoyi.system.service.AccountService;
import com.ruoyi.system.service.OrderService;
import com.ruoyi.system.service.ProductService;
import io.seata.core.context.RootContext;
import io.seata.spring.annotation.GlobalTransactional;
@Service
public class OrderServiceImpl implements OrderService
{
private static final Logger log = LoggerFactory.getLogger(OrderServiceImpl.class);
@Resource
private OrderMapper orderMapper;
@Autowired
private AccountService accountService;
@Autowired
private ProductService productService;
@DS("order") // 每一层都需要使用多数据源注解切换所选择的数据库
@Override
@Transactional
@GlobalTransactional // 重点 第一个开启事务的需要添加seata全局事务注解
public void placeOrder(PlaceOrderRequest request)
{
log.info("=============ORDER START=================");
Long userId = request.getUserId();
Long productId = request.getProductId();
Integer amount = request.getAmount();
log.info("收到下单请求,用户:{}, 商品:{},数量:{}", userId, productId, amount);
log.info("当前 XID: {}", RootContext.getXID());
Order order = new Order(userId, productId, 0, amount);
orderMapper.insert(order);
log.info("订单一阶段生成，等待扣库存付款中");
// 扣减库存并计算总价
Double totalPrice = productService.reduceStock(productId, amount);
// 扣减余额
accountService.reduceBalance(userId, totalPrice);
order.setStatus(1);
order.setTotalPrice(totalPrice);
orderMapper.updateById(order);
log.info("订单已成功下单");
log.info("=============ORDER END=================");
}
}
ProductService.java
package com.ruoyi.system.service.impl;
import javax.annotation.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import com.baomidou.dynamic.datasource.annotation.DS;
import com.ruoyi.system.domain.Product;
import com.ruoyi.system.mapper.ProductMapper;
import com.ruoyi.system.service.ProductService;
import io.seata.core.context.RootContext;
@Service
public class ProductServiceImpl implements ProductService
{
private static final Logger log = LoggerFactory.getLogger(ProductServiceImpl.class);
@Resource
private ProductMapper productMapper;
/**
* 事务传播特性设置为 REQUIRES_NEW 开启新的事务 重要！！！！一定要使用REQUIRES_NEW
*/
@DS("product")
@Transactional(propagation = Propagation.REQUIRES_NEW)
@Override
public Double reduceStock(Long productId, Integer amount)
{
log.info("=============PRODUCT START=================");
log.info("当前 XID: {}", RootContext.getXID());
// 检查库存
Product product = productMapper.selectById(productId);
Integer stock = product.getStock();
log.info("商品编号为 {} 的库存为{},订单商品数量为{}", productId, stock, amount);
if (stock < amount)
{
log.warn("商品编号为{} 库存不足，当前库存:{}", productId, stock);
throw new RuntimeException("库存不足");
}
log.info("开始扣减商品编号为 {} 库存,单价商品价格为{}", productId, product.getPrice());
// 扣减库存
int currentStock = stock - amount;
product.setStock(currentStock);
productMapper.updateById(product);
double totalPrice = product.getPrice() * amount;
log.info("扣减商品编号为 {} 库存成功,扣减后库存为{}, {} 件商品总价为 {} ", productId, currentStock, amount, totalPrice);
log.info("=============PRODUCT END=================");
return totalPrice;
}
}
OrderController.java
package com.ruoyi.system.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.ruoyi.system.domain.dto.PlaceOrderRequest;
import com.ruoyi.system.service.OrderService;
import io.swagger.annotations.ApiOperation;
@RestController
@RequestMapping("/order")
public class OrderController
{
@Autowired
private OrderService orderService;
@PostMapping("/placeOrder")
public String placeOrder(@Validated @RequestBody PlaceOrderRequest request)
{
orderService.placeOrder(request);
return "下单成功";
}
@PostMapping("/test1")
@ApiOperation("测试商品库存不足-异常回滚")
public String test1()
{
// 商品单价10元，库存20个,用户余额50元，模拟一次性购买22个。 期望异常回滚
orderService.placeOrder(new PlaceOrderRequest(1L, 1L, 22));
return "下单成功";
}
@PostMapping("/test2")
@ApiOperation("测试用户账户余额不足-异常回滚")
public String test2()
{
// 商品单价10元，库存20个，用户余额50元，模拟一次性购买6个。 期望异常回滚
orderService.placeOrder(new PlaceOrderRequest(1L, 1L, 6));
return "下单成功";
}
}
AccountMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruoyi.system.mapper.AccountMapper">
<resultMap type="Account" id="AccountResult">
<id property="id" column="id" />
<result property="balance" column="balance" />
<result property="lastUpdateTime" column="last_update_time" />
</resultMap>
<select id="selectById" parameterType="Account" resultMap="AccountResult">
select id, balance, last_update_time
from account where id = #{userId}
</select>
<update id="updateById" parameterType="Account">
update account set balance = #{balance}, last_update_time = sysdate() where id = #{id}
</update>
</mapper>
OrderMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruoyi.system.mapper.OrderMapper">
<resultMap type="Order" id="OrderResult">
<id property="id" column="id" />
<result property="userId" column="user_id" />
<result property="productId" column="product_id" />
<result property="amount" column="amount" />
<result property="totalPrice" column="total_price" />
<result property="status" column="status" />
<result property="addTime" column="add_time" />
<result property="lastUpdateTime" column="last_update_time" />
</resultMap>
<insert id="insert" parameterType="Order" useGeneratedKeys="true" keyProperty="id">
insert into p_order (
<if test="userId != null and userId != '' ">user_id,</if>
<if test="productId != null and productId != '' ">product_id,</if>
<if test="amount != null and amount != '' ">amount,</if>
<if test="totalPrice != null and totalPrice != '' ">total_price,</if>
<if test="status != null and status != ''">status,</if>
add_time
)values(
<if test="userId != null and userId != ''">#{userId},</if>
<if test="productId != null and productId != ''">#{productId},</if>
<if test="amount != null and amount != ''">#{amount},</if>
<if test="totalPrice != null and totalPrice != ''">#{totalPrice},</if>
<if test="status != null and status != ''">#{status},</if>
sysdate()
)
</insert>
<update id="updateById" parameterType="Order">
update p_order
<set>
<if test="userId != null and userId != ''">user_id = #{userId},</if>
<if test="productId != null and productId != ''">product_id = #{productId},</if>
<if test="amount != null and amount != ''">amount = #{amount},</if>
<if test="totalPrice != null and totalPrice != ''">total_price = #{totalPrice},</if>
<if test="status != null and status != ''">status = #{status},</if>
last_update_time = sysdate()
</set>
where id = #{id}
</update>
</mapper>
ProductMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ruoyi.system.mapper.ProductMapper">
<resultMap type="Product" id="ProductResult">
<id property="id" column="id" />
<result property="price" column="price" />
<result property="stock" column="stock" />
<result property="lastUpdateTime" column="last_update_time" />
</resultMap>
<select id="selectById" parameterType="Product" resultMap="ProductResult">
select id, price, stock, last_update_time
from product where id = #{productId}
</select>
<update id="updateById" parameterType="Product">
update product set price = #{price}, stock = #{stock}, last_update_time = sysdate() where id = #{id}
</update>
</mapper>
测试验证
使用Postman工具测试接口，注意观察运行日志，至此分布式事务集成案例全流程完毕
模拟正常下单，买一个商品 http://localhost:9201/order/placeOrder
Content-Type/application/json
{
"userId": 1,
"productId": 1,
"amount": 1
}
模拟库存不足，事务回滚 http://localhost:9201/order/placeOrder
Content-Type/application/json
{
"userId": 1,
"productId": 1,
"amount": 22
}
模拟用户余额不足，事务回滚 http://localhost:9201/order/placeOrder
Content-Type/application/json
{
"userId": 1,
"productId": 1,
"amount": 6
}
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