正文
1、解决的应用场景是分布式事务,每个服务有独立的数据库。
2、例如:A服务的数据库是A1,B服务的数据库是B2,A服务通过feign接口调用B服务,B涉及提交数据到B2,业务是在B提交数据之后,在A服务内报错。
所以,希望B能回滚事务。这就是跨库的数据回滚
下载
seata下载地址
seata的配置
1、创建一个数据库,把seata的表生成出来
2、修改seata配置文件
注意有其他的需求可以参考example文件,我这里直接展示本地修改后的
# Copyright 1999-2019 Seata.io Group.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
server:
port: 7091
spring:
application:
name: seata-server
logging:
config: classpath:logback-spring.xml
file:
path: ${user.home}/logs/seata
#extend:
#logstash-appender:
# destination: 127.0.0.1:4560
#kafka-appender:
# bootstrap-servers: 127.0.0.1:9092
# topic: logback_to_logstash
console:
user:
username: seata
password: seata
seata:
#data-source-proxy-mode: XA
#tx-service-group: default
#service:
#vgroup-mapping: # 事务组与cluster的映射关系
# default_tx_group: DEFAULT
#grouplist:
# DEFAULT: 127.0.0.1:8091
config:
# support: nacos, consul, apollo, zk, etcd3
type: nacos
nacos:
application: seata-server
server-addr: 127.0.0.1:8848
group : "WEIMEIZI_GROUP"
namespace:
username: "nacos"
password: "nacos"
#data-id: seataServer.properties
registry:
# support: nacos, eureka, redis, zk, consul, etcd3, sofa
type: nacos
nacos:
application: seata-server
server-addr: 127.0.0.1:8848
group: "WEIMEIZI_GROUP"
namespace:
cluster: default
username: "nacos"
password: "nacos"
store:
# support: file 、 db 、 redis
mode: db
# 数据源驱动类名称
db:
datasource: druid
db-type: mysql
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true
user: root
password: root
min-conn: 10
max-conn: 100
global-table: global_table
branch-table: branch_table
lock-table: lock_table
distributed-lock-table: distributed_lock
query-limit: 1000
max-wait: 5000
# server:
# service-port: 8091 #If not configured, the default is '${server.port} + 1000'
security:
secretKey: SeataSecretKey0c382ef121d778043159209298fd40bf3850a017
tokenValidityInMilliseconds: 1800000
ignore:
urls: /,/**/*.css,/**/*.js,/**/*.html,/**/*.map,/**/*.svg,/**/*.png,/**/*.jpeg,/**/*.ico,/api/v1/auth/login
3、修改nacos配置文件
新增:
seata:
data-source-proxy-mode: XA
tx-service-group: default
service.vgroupMapping.default: default
service.default.grouplist: 127.0.0.1:8091
注意如果你用的是其他版本的seata,可能service.vgroupMapping.default和 service.default.grouplist在其他版本命名不一样,报错就修改
4、涉及到分布式事务的数据库都要创建undo_log表
这张表在seata官方包里是没有的,如果不创建,代码会报错,找不到表
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log` (
`branch_id` bigint(20) NOT NULL COMMENT '分支事务ID',
`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '全局事务ID',
`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '上下文',
`rollback_info` longblob NOT NULL COMMENT '回滚信息',
`log_status` int(11) NOT NULL COMMENT '状态,0正常,1全局已完成',
`log_created` datetime(6) NOT NULL COMMENT '创建时间',
`log_modified` datetime(6) NOT NULL COMMENT '修改时间',
UNIQUE INDEX `ux_undo_log`(`xid`, `branch_id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = 'AT transaction mode undo table' ROW_FORMAT = Compact;
SET FOREIGN_KEY_CHECKS = 1;
服务注册
满足1、2、3步后,启动
就会发现nacos注册上了seata
项目的代码
主要是两个注解:
@EnableAutoDataSourceProxy
@GlobalTransactional(rollbackFor = Exception.class)
A服务的方法:
B服务的方法:
B服务的方法正常执行并提交数据到B库,但是A服务报错了,所以B服务得回滚数据
A、B的Application都要加上@EnableAutoDataSourceProxy
注意:引入的pom文件:
两个服务的pom都要引入seata,注意:有个包叫做seata-all,这个包不要一起引入进去,否则会报:数据源错误
<!-- Seata-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<version>2.0.4</version>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-spring-boot-starter</artifactId>
<version>1.7.0</version>
</dependency>
结语
事务回滚成功是根据XID,以下是成功回滚的截图
A服务的控制台输出:
B服务的控制台输出:文章来源:https://www.toymoban.com/news/detail-681728.html
备注
如果因为nacos的配置文件过大,导致netty报错,那么,就修改netty的内存,文件是application.yml文章来源地址https://www.toymoban.com/news/detail-681728.html
#服务器端口
server:
port: 8200
netty:
max-chunk-size: 1545270062
max-initial-line-length: 1545270062
h2c-max-content-length: 1545270062
到了这里,关于分布式系统的多数据库,实现分布式事务回滚(1.7.0 seata整合2.0.4nacos)的文章就介绍完了。如果您还想了解更多内容,请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章,希望大家以后多多支持TOY模板网!