seata处理分布式问题
seata处理分布式问题
分布式事务问题
一次事务操作需要跨多个数据源后需要跨多个系统进行远程调用，就会产生分布式事务问题
单体应用被拆分成微服务应用，原来的三个模块被拆分成三个独立的应用，分别使用三个独立的数据源。
业务操作需要调用三个服务来完成。此时服务内部的数据一致性由本地事务来保证，但是全局的数据一致性问题没发保证。
seata简介
seata是一款开源的分布式事务解决方案，致力于在微服务架构下提供高性能和简单易用的分布式事务服务。
一个典型的分布式事务过程
- 分布式处理过程的唯一ID+三组件模型
- Transaction ID XID：全局唯一的事务ID
- Transaction Coordinator(TC)：事务协调器，维护全局事务的运行状态，负责协调并驱动全局事务的提交或回滚。
- Transaction Manager(TM)：控制全局事务的边界，负责开启一个全局事务，并最终发起全局提交或全局回滚的决议。
- Resource Manager(RM)：控制分支事务，负责分支注册、状态汇报，并接受事务协调器的指令，驱动分支(本地)事务的提交和回滚。
- TM向TC申请开启一个全局事务，全局事务创建成功并生成一个全局唯一的XID；
- XID在微服务调用链路的上下文中传播。
- RM向TC注册分支事务，将其纳入XID对应全局事务的管辖；
- TM向TC发起针对XID的全局提交或回滚决议；
- TC调度XID下管辖的全部分支事务完成提交或回滚请求。
seata安装
下载seata并解压
修改配置文件
创建seata数据库
运行db_store.sql文件
先启动nacos后启动seata
Seata业务数据库准备
创建3个服务，一个订单服务，一个库存服务，一个账户服务
当用户下单时，会在订单服务中创建一个订单，然后通过远程调用库存服务来扣减下单商品的库存，再通过远程调用账户服务来扣减用户账户里面的余额，最后在订单服务中修改订单状态为已完成。
该操作跨越三个数据库，有两次远程调用，很明显会有分布式事务问题。
创建业务数据库
seata_order：存储订单的数据库；
seata_order：存储库存的数据；
seata_account：存储账户信息的数据库；
创建对应的业务表
seata_order数据库下创建t_order表
CREATE DATABASE seata_order;
USE seata_order;
CREATE TABLE t_order(
id BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY ,
user_id BIGINT(11) DEFAULT NULL COMMENT '用户id',
product_id BIGINT(11) DEFAULT NULL COMMENT '产品id',
count INT(11) DEFAULT NULL COMMENT '数量',
money DECIMAL(11,0) DEFAULT NULL COMMENT '金额',
status INT(1) DEFAULT NULL COMMENT '订单状态：0创建中，1已完结'
)ENGINE=InnoDB AUTO_INCREMENT=7 CHARSET=utf8;
seata_storage数据库下创建t_storage表
CREATE DATABASE seata_storage;
USE seata_storage;
CREATE TABLE t_storage(
id BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY ,
product_id BIGINT(11) DEFAULT NULL COMMENT '产品id',
total INT(11) DEFAULT NULL COMMENT '总库存',
used INT(11) DEFAULT NULL COMMENT '已用库存',
residue INT(11) DEFAULT NULL COMMENT '剩余库存'
)ENGINE=InnoDB AUTO_INCREMENT=7 CHARSET=utf8;
INSERT INTO t_storage(id, product_id, total, used, residue) VALUES(1,1,100,0,100);
seata_account数据库下创建t_account表
CREATE DATABASE seata_account;
USE seata_account;
CREATE TABLE t_account(
id BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY ,
user_id BIGINT(11) DEFAULT NULL COMMENT '用户id',
total DECIMAL(10,0) DEFAULT NULL COMMENT '总额度',
used DECIMAL(10,0) DEFAULT NULL COMMENT '已用额度',
residue DECIMAL(10,0) DEFAULT 0 COMMENT '剩余可用额度'
)ENGINE=InnoDB AUTO_INCREMENT=7 CHARSET=utf8;
INSERT INTO t_account(id, user_id, total, used, residue) VALUES(1,1,1000,0,1000);
在每一个数据库下面执行db_undo_log.sql文件
seata-order-service2001
创建子项目(seata-order-service2001)
pom.xml文件
<dependencies>
<!--nacos-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--seata-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<artifactId>seata-all</artifactId>
<groupId>io.seata</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>0.9.0</version>
</dependency>
<!--feign-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!--web-actuator-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--mysql-druid-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.37</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
创建application.yml配置文件
server:
port: 2001
spring:
application:
name: seata-order-service
cloud:
alibaba:
seata:
#自定义事务组名称需要与seata-server中的对应
tx-service-group: fsp_tx_group
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order
username: root
password: 123456
feign:
hystrix:
enabled: false
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
两个配置文件file.conf和registry.conf
transport {
# tcp udt unix-domain-socket
type = "TCP"
#NIO NATIVE
server = "NIO"
#enable heartbeat
heartbeat = true
#thread factory for netty
thread-factory {
boss-thread-prefix = "NettyBoss"
worker-thread-prefix = "NettyServerNIOWorker"
server-executor-thread-prefix = "NettyServerBizHandler"
share-boss-worker = false
client-selector-thread-prefix = "NettyClientSelector"
client-selector-thread-size = 1
client-worker-thread-prefix = "NettyClientWorkerThread"
# netty boss thread size,will not be used for UDT
boss-thread-size = 1
#auto default pin or 8
worker-thread-size = 8
}
shutdown {
# when destroy server, wait seconds
wait = 3
}
serialization = "seata"
compressor = "none"
}
service {
vgroup_mapping.fsp_tx_group = "default"
default.grouplist = "127.0.0.1:8091"
enableDegrade = false
disable = false
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
disableGlobalTransaction = false
}
client {
async.commit.buffer.limit = 10000
lock {
retry.internal = 10
retry.times = 30
}
report.retry.count = 5
tm.commit.retry.count = 1
tm.rollback.retry.count = 1
}
## transaction log store
store {
## store mode: file、db
mode = "db"
## file store
file {
dir = "sessionStore"
# branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
max-branch-session-size = 16384
# globe session size , if exceeded throws exceptions
max-global-session-size = 512
# file buffer size , if exceeded allocate new buffer
file-write-buffer-cache-size = 16384
# when recover batch read size
session.reload.read_size = 100
# async, sync
flush-disk-mode = async
}
## database store
db {
## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
datasource = "dbcp"
## mysql/oracle/h2/oceanbase etc.
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "123456"
min-conn = 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
lock {
## the lock store mode: local、remote
mode = "remote"
local {
## store locks in user's database
}
remote {
## store locks in the seata's server
}
}
recovery {
#schedule committing retry period in milliseconds
committing-retry-period = 1000
#schedule asyn committing retry period in milliseconds
asyn-committing-retry-period = 1000
#schedule rollbacking retry period in milliseconds
rollbacking-retry-period = 1000
#schedule timeout retry period in milliseconds
timeout-retry-period = 1000
}
transaction {
undo.data.validation = true
undo.log.serialization = "jackson"
undo.log.save.days = 7
#schedule delete expired undo_log in milliseconds
undo.log.delete.period = 86400000
undo.log.table = "undo_log"
}
## metrics settings
metrics {
enabled = false
registry-type = "compact"
# multi exporters use comma divided
exporter-list = "prometheus"
exporter-prometheus-port = 9898
}
support {
## spring
spring {
# auto proxy the DataSource bean
datasource.autoproxy = false
}
}
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "nacos"
nacos {
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:8761/eureka"
application = "default"
weight = "1"
}
redis {
serverAddr = "localhost:6379"
db = "0"
}
zk {
cluster = "default"
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
consul {
cluster = "default"
serverAddr = "127.0.0.1:8500"
}
etcd3 {
cluster = "default"
serverAddr = "http://localhost:2379"
}
sofa {
serverAddr = "127.0.0.1:9603"
application = "default"
region = "DEFAULT_ZONE"
datacenter = "DefaultDataCenter"
cluster = "default"
group = "SEATA_GROUP"
addressWaitTime = "3000"
}
file {
name = "file.conf"
}
}
config {
# file、nacos 、apollo、zk、consul、etcd3
type = "file"
nacos {
serverAddr = "localhost"
namespace = ""
}
consul {
serverAddr = "127.0.0.1:8500"
}
apollo {
app.id = "seata-server"
apollo.meta = "http://192.168.1.204:8801"
}
zk {
serverAddr = "127.0.0.1:2181"
session.timeout = 6000
connect.timeout = 2000
}
etcd3 {
serverAddr = "http://localhost:2379"
}
file {
name = "file.conf"
}
}
domian下的实体类
package com.atguigu.springcloud.alibaba.domain;
public class CommonResult<T> {
private Integer code;
private String message;
private T data;
public CommonResult(Integer code, String message) {
this.code = code;
this.message = message;
}
public CommonResult() {
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
@Override
public String toString() {
return "CommonResult{" +
"code=" + code +
", message='" + message + '\'' +
", data=" + data +
'}';
}
}
package com.atguigu.springcloud.alibaba.domain;
import java.math.BigDecimal;
public class Order {
private Long id;
private Long userId;
private Long productId;
private Integer count;
private BigDecimal money;
private Integer status;
public Order(Long id, Long userId, Long productId, Integer count, BigDecimal money, Integer status) {
this.id = id;
this.userId = userId;
this.productId = productId;
this.count = count;
this.money = money;
this.status = status;
}
public Order() {
}
public Long getId() {
return id;
}
public void setId(Long 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 Integer getCount() {
return count;
}
public void setCount(Integer count) {
this.count = count;
}
public BigDecimal getMoney() {
return money;
}
public void setMoney(BigDecimal money) {
this.money = money;
}
public Integer getStatus() {
return status;
}
public void setStatus(Integer status) {
this.status = status;
}
@Override
public String toString() {
return "Order{" +
"id=" + id +
", userId=" + userId +
", productId=" + productId +
", count=" + count +
", money=" + money +
", status=" + status +
'}';
}
}
Dao接口及实现
@Mapper
public interface OrderDao {
//新建订单
void create(Order order);
//修改订单状态
void update(@Param("userID") Long userId,@Param("status") Integer status);
}
resouces文件夹下新建mapper文件夹
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.atguigu.springcloud.alibaba.dao.OrderDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Order">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="user_id" property="userId" jdbcType="BIGINT"/>
<result column="product_id" property="productId" jdbcType="BIGINT"/>
<result column="count" property="count" jdbcType="INTEGER"/>
<result column="money" property="money" jdbcType="DECIMAL"/>
<result column="status" property="status" jdbcType="INTEGER"/>
</resultMap>
<insert id="create">
insert into t_order (id,user_id,product_id,count,money,status)
values (null,#{userId},#{productId},#{count},#{money},0);
</insert>
<update id="update">
update t_order set status = 1 where user_id=#{userId} and status = #{status};
</update>
</mapper>
Service接口及实现
public interface OrderService {
void create(Order order);
}
@FeignClient(value = "seata-account-service")
public interface AccountService {
@PostMapping(value = "/account/decrease")
CommonResult decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}
@FeignClient(value = "seata-storage-service")
public interface StorageService {
@PostMapping(value = "/storage/decrease")
CommonResult decrease(@RequestParam("productId") Long productId,@RequestParam("count") Integer count);
}
实现类
@Service
public class OrderServiceImpl implements OrderService {
@Resource
private OrderDao orderDao;
@Resource
private AccountService accountService;
@Resource
private StorageService storageService;
@Override
public void create(Order order) {
System.out.println("新建订单");
orderDao.create(order);
System.out.println("订单微服务开始调用库存，做扣减");
storageService.decrease(order.getProductId(),order.getCount());
System.out.println("订单微服务开始调用账户，做扣减");
accountService.decrease(order.getUserId(),order.getMoney());
//修改微服务订单状态
System.out.println("修改订单状态开始");
orderDao.update(order.getUserId(),0);
System.out.println("订单修改结束");
}
}
Config配置
@Configuration
public class DataSourceProxyConfig {
@Value("${mybatis.mapperLocations}")
private String mapperLocations;
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource(){
return new DruidDataSource();
}
@Bean
public DataSourceProxy dataSourceProxy(DataSource dataSource) {
return new DataSourceProxy(dataSource);
}
@Bean
public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSourceProxy);
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
return sqlSessionFactoryBean.getObject();
}
}
@Configuration
@MapperScan("{com.atguigu.springcloud.alibaba}")
public class MyBatisConfig {
}
主启动类
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableDiscoveryClient
@EnableFeignClients
public class SeataStorageServiceApplication2002 {
public static void main(String[] args) {
SpringApplication.run(SeataStorageServiceApplication2002.class,args);
}
}
主启动类
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源的自动装配
@EnableDiscoveryClient
@EnableFeignClients
@ComponentScan("com.atguigu.springcloud.alibaba.domain")
public class SeataOrderMainApp2001 {
public static void main(String[] args) {
SpringApplication.run(SeataOrderMainApp2001.class,args);
}
}
seata-storage-service2002
新建子项目(seata-storage-service2002)
pom.xml
<dependencies>
<!--nacos-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--seata-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<artifactId>seata-all</artifactId>
<groupId>io.seata</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>0.9.0</version>
</dependency>
<!--feign-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.37</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
application.yml
server:
port: 2002
spring:
application:
name: seata-storage-service
cloud:
alibaba:
seata:
tx-service-group: fsp_tx_group
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_storage
username: root
password: 123456
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
domain
public class CommonResult<T> {
private Integer code;
private String message;
private T data;
public CommonResult(Integer code, String message) {
this.code = code;
this.message = message;
}
public CommonResult() {
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
@Override
public String toString() {
return "CommonResult{" +
"code=" + code +
", message='" + message + '\'' +
", data=" + data +
'}';
}
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Storage {
private Long id;
private Long productId;
private Integer total;
private Integer used;
private Integer residue;
}
Dao接口及实现
@Mapper
public interface StorageDao {
void decrease(@Param("productId") Long productId,@Param("count") Integer count);
}
StorageMapper
<?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.atguigu.springcloud.alibaba.dao.OrderDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Order">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="user_id" property="userId" jdbcType="BIGINT"/>
<result column="product_id" property="productId" jdbcType="BIGINT"/>
<result column="count" property="count" jdbcType="INTEGER"/>
<result column="money" property="money" jdbcType="DECIMAL"/>
<result column="status" property="status" jdbcType="INTEGER"/>
</resultMap>
<update id="decrease">
update t_storage set used = used+ #{count},residue = residue - #{count} where product_id = #{productId}
</update>
</mapper>
service接口及实现
public interface StorageService {
void decrease(Long productId,Integer count);
}
@Service
public class StorageServiceImpl implements StorageService {
private static final Logger LOGGER = LoggerFactory.getLogger(StorageServiceImpl.class);
@Resource
private StorageDao storageDao;
@Override
public void decrease(Long productId, Integer count) {
System.out.println("--------Storage扣减库存开始-------");
storageDao.decrease(productId, count);
System.out.println("--------Storage减少库存结束-------");
}
}
controller
@RestController
public class StorageController {
@Autowired
private StorageService storageService;
@RequestMapping("/storage/decrease")
public CommonResult decrease(Long productId,Integer count) {
storageService.decrease(productId, count);
return new CommonResult(200,"扣减库存成功");
}
}
配置文件DataSourceProxyConfig.java和MyBatis.java
file.conf和reqistry.conf
都和子项目（2001）一样
seata-account-service2003
application.yml
server:
port: 2003
spring:
application:
name: seata-account-service
cloud:
alibaba:
seata:
tx-service-group: fsp_tx_group
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_account
username: root
password: 123456
feign:
hystrix:
enabled: false
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
domain
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Account {
private Long id;
private Long userId;
private BigDecimal total;
private BigDecimal used;
private BigDecimal residue;
}
public class CommonResult<T> {
private Integer code;
private String message;
private T data;
public CommonResult(Integer code, String message) {
this.code = code;
this.message = message;
}
public CommonResult() {
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public T getData() {
return data;
}
public void setData(T data) {
this.data = data;
}
@Override
public String toString() {
return "CommonResult{" +
"code=" + code +
", message='" + message + '\'' +
", data=" + data +
'}';
}
}
Dao接口及实现
@Mapper
public interface AccountDao {
void decrease(@Param("userId") Long userId, @Param("money")BigDecimal money);
}
<?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.atguigu.springcloud.alibaba.dao.OrderDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Order">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="user_id" property="userId" jdbcType="BIGINT"/>
<result column="product_id" property="productId" jdbcType="BIGINT"/>
<result column="count" property="count" jdbcType="INTEGER"/>
<result column="money" property="money" jdbcType="DECIMAL"/>
<result column="status" property="status" jdbcType="INTEGER"/>
</resultMap>
<update id="decrease">
UPDATE t_account SET residue = residue - #{money},used = used + #{money} where user_id = #{userId}
</update>
</mapper>
Service接口及实现
public interface AccountService {
void decrease(@Param("userId") Long userId, @Param("money") BigDecimal money);
}
public class AccountServiceImpl implements AccountService {
private static final Logger LOGGER = LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
private AccountDao accountDao;
@Override
public void decrease(Long userId, BigDecimal money) {
System.out.println("---------account 扣减账户余额开始");
accountDao.decrease(userId, money);
System.out.println("---------account 扣减账户余额结束");
}
}
Controller
@RestController
public class AccountController {
@Resource
AccountService accountService;
@RequestMapping("/account/decrease")
public CommonResult decrease(@RequestParam("userId") Long userId, @RequestParam("money")BigDecimal money){
accountService.decrease(userId, money);
return new CommonResult(200,"扣减账户余额成功");
}
}
主启动类
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableDiscoveryClient
@EnableFeignClients
public class SeataAccountMainApp2003 {
public static void main(String[] args) {
SpringApplication.run(SeataAccountMainApp2003.class,args);
}
}
配置文件DataSourceProxyConfig.java和MyBatis.java
file.conf和reqistry.conf
都和子项目（2001）一样
seata补充
回滚方式是用“before image”还原业务数据；但在还原前要首先校验脏写，对比“数据库当前业务数据”和“after image”，如果两份数据完全一致就说明没有脏读，可以还原业务数据，如果不一致就说明有脏读，出现脏读就需要转人工处理。
