目录
可以查看官网：快速启动 | Seata
一、建立undo_log表
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log
CREATE TABLE `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,
`ext` varchar(100) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;二、安装事务协调器：seata-server
三、整合
（一） 导入依赖 spring-cloud-starter-alibaba-seata seata-all 0.7.1
（二） 启动seata-server（TC）
修改配置 registry.conf 修改seata的注册中心为nacos，（文件配置放在file.conf中，不修改）
registry.conf文件修改后如下：
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa seata的注册中心
type = "nacos" //修改的地方
nacos {
serverAddr = "localhost:8848"
namespace = "public"
cluster = "default"
}
eureka {
serviceUrl = "http://localhost:1001/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 = "public"
cluster = "default"
}
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"
}
}
（三） 所有想要用到分布式事务的微服务使用seata DatasourceProxy代理自己的数据源
@Autowired
DataSourceProperties dataSourceProperties;
@Bean
public DataSource dataSource(DataSourceProperties properties) {
HikariDataSource dataSource = dataSourceProperties.initializeDataSourceBuilder().type(HikariDataSource.class).build();
if (StringUtils.hasText(properties.getName())) {
dataSource.setPoolName(properties.getName());
}
return new DataSourceProxy(dataSource);
}（四） 每个微服务，都必须导入(放resource下)
register.conf和 file.conf(修改vgroup_mapping.{application.name}-fescar-service-group = "default")
（五） 在分布式事务的入口方法上设置@GlobalTransactional（TM），在每一小事务上设置@Transactional（RM）
远程调用的方法上面也要添加@Transactional
@GlobalTransactional //seata分布式事务控制
@Transactional
@Override
public SubmitOrderResponseVo submitOrder(OrderSubmitVo vo) {
submitVoThreadLocal.set(vo);
MemberResVo memberResVo = LoginUserInterceptor.loginUser.get();
SubmitOrderResponseVo response = new SubmitOrderResponseVo();
response.setCode(0);
String redisToken = redisTemplate.opsForValue().get(OrderConstant.USER_ORDER_TOKEN_PREFIX + memberResVo.getId());
String orderToken = vo.getOrderToken();
// 成功返回1 失败返回0
String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
// 保证原子性
Long result = redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class), Arrays.asList(OrderConstant.USER_ORDER_TOKEN_PREFIX + memberResVo.getId()), orderToken);
if(result == 0L) {
// 验证失败
response.setCode(1);
return response;
} else {
// 下单，创建订单，校验令牌，检验价格，锁库存
// TODO 1、创建订单，订单项等信息
OrderCreateTo order = createOrder();
// TODO 2、验价
BigDecimal payAmount = order.getOrder().getPayAmount();
if(Math.abs(payAmount.subtract(vo.getPayPrice()).doubleValue()) < 0.01) {
// 金额对比成功后保存订单
// TODO 3、保存订单
saveOrder(order);
WareSkuLockVo wareSkuLockVo = new WareSkuLockVo();
wareSkuLockVo.setOrderSn(order.getOrder().getOrderSn());
List<OrderItemVo> collect = order.getOrderItems().stream().map(item -> {
OrderItemVo orderItemVo = new OrderItemVo();
orderItemVo.setCount(item.getSkuQuantity());
orderItemVo.setSkuId(item.getSkuId());
orderItemVo.setTitle(item.getSkuName());
return orderItemVo;
}).collect(Collectors.toList());
wareSkuLockVo.setLocks(collect);
// TODO 4、锁库存
// 出异常后，因为远程锁库存成功，但是忘了原因超时了，订单回滚，库存不回滚
R r = wareFeignService.orderLockStock(wareSkuLockVo);
if(r.getCode() == 0) {
// 锁成功
response.setOrder(order.getOrder());
// TODO 5 出异常
int i = 10/0;
return response;
} else {
// 锁定失败
// 抛异常才能使事务回滚
response.setCode(3);
throw new NoStockException((String)r.get("msg"));
// return response;
}
} else {
response.setCode(2); // 金额对比失败
return response;
}
}注意：
这种方法其实并不适用于下单等高并发场景。seata的AT模式适用于并发量不大的场景，比如说后台商家添加商品什么的，而不适用于高并发场景。因为锁太多导致串行，没法并发。
