SpringLoud Alibaba

目录

Spring Cloud Alibaba

  • 父工程pom

    <dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
    <version>2.1.0.RELEASE</version>
    <type>pom</type>
    <scope>import</scope>
</dependency>

Nacos服务注册和配置中心

相当于Eureka + Config + Bus， 和Eureka一样都是AP模型（只支持注册临时实例+高可用+分区分治），但支持CP和AP切换

服务提供者

  • pom依赖：spring-cloud-starter-alibaba-nacos-discovery

  • 命令运行成功后直接访问http://localhost:8848/nacos

  • yml

    spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #配置Nacos地址

  • 启动类注解：@EnableDiscoveryClient

服务消费者

  • pom依赖：spring-cloud-starter-alibaba-nacos-discovery ， 包含了Ribbon

  • yml

    spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848

#消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者)
service-url:
  nacos-user-service: http://nacos-payment-provider

  • 可以用Ribbon + RestTemplate进行远程调用

配置中心

  • pom依赖：spring-cloud-starter-alibaba-nacos-config

  • 全局配置文件boostrap.yml

    spring:
  application:
    name: nacos-config-client
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos服务注册中心地址
      config:
        server-addr: localhost:8848 #Nacos作为配置中心地址
        file-extension: yaml #指定读取yaml格式的配置文件
        group: DEV_GROUP  
        namespace: 7d8f0f5a-6a53-4785-9686-dd460158e5d4

# nacos上配置文件规则：${spring.application.name}-${spring.profile.active}.${spring.cloud.nacos.config.file-extension}
# nacos-config-client-dev.yaml

image-20200904231143004

  • application.yml

    spring:
  profiles:
    active: dev # 表示开发环境
    #active: test # 表示测试环境
    #active: prod # 生成环境

  • Nacos支持配置动态刷新：@RefreshScope //支持Nacos的动态刷新功能。

  • 启动类注解：@EnableDiscoveryClient

分类配置

image-20200905000009508

image-20200905000105474

DataID方案

指定spring.profile.active和配置文件的DataID来使不同环境下读取不同的配置

nacos上配置文件规则：${spring.application.name}-${spring.profile.active}.${spring.cloud.nacos.config.file-extension} => nacos-config-client-dev.yaml

Group方案

通过Group实现环境区分

Namespace方案

不同的Namespace之间是隔离的

  • bootstrap.yml

    spring:
  cloud:
    nacos:
      config:
        server-addr: localhost:8848 #Nacos作为配置中心地址
        file-extension: yaml #指定yaml格式的配置  DataID方案
        group: DEV_GROUP  # Group方案
        namespace: 7d8f0f5a-6a53-4785-9686-dd460158e5d4   # 在nacos中新建命名空间后Namespace的id

  • yml选择读取的配置文件

    spring:
  profiles:
    active: dev # 表示开发环境
    #active: test # 表示测试环境
    #active: info

Nacos集群和持久化配置(重要)

image-20200905110415450

derby到mysql切换配置步骤

Nacos默认自带的是嵌入式数据库derby，目前只支持mysql 数据源配置

  • nacos\conf目录下找到sql脚本：nacos-mysql.sql ， 在数据库执行脚本，配置信息存储在数据库nacos-config
  • nacos\conf目录下找到application.properties，修改该文件，修改内容在nacos官网，修改mysql用户名密码即可

Nacos集群配置

  • Linux服务器上nacos的集群配置cluster.conf， 先备份后配置, 根据自己的linux的ip配置

    192.168.xxx.xxx:3333
192.168.xxx.xxx:4444
192.168.xxx.xxx:5555

  • 备份后编辑Nacos的启动脚本startup.sh,使他能够接受不同的启动端口image-20200905122953529

    image-20200905123237668

  • nginx.conf备份后修改

    image-20200905123519126

    按照指定配置文件启动nginx：./nginx -c /usr/local/nginx/conf/nginx.conf

  • 根据端口启动3个命令： ./startup.sh -p 3333 、 ./startup.sh -p 4444 、 ./startup.sh -p 5555

  • 测试通过nginx访问nacos： http://192.168.111.144:1111/nacos/#/login

  • 微服务springalibaba-provider-payment9002启动注册进nacos集群， 修改配置yml文件中的nacos地址：server-addr: 192.168.111.144.1111

Sentinel实现熔断与限流

  • 下载安装Sentiel控制台：https://github.com/alibaba/Sentinel/releases

  • 8080端口不能被占用

  • pom依赖：spring-cloud-starter-alibaba-sentinel 、 sentinel-datasource-nacos

    <!-- https://mvnrepository.com/artifact/com.alibaba.cloud/spring-cloud-starter-alibaba-sentinel -->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
    <version>2.2.1.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.alibaba.csp/sentinel-datasource-nacos -->
<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-datasource-nacos</artifactId>
    <version>1.7.1</version>
    <scope>test</scope>
</dependency>

  • yml

    spring:
  application:
    name: cloudalibaba-sentinel-service
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #Nacos服务注册中心地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard地址
        port: 8719
      datasource:
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow
management:  # 开启监控
  endpoints:
    web:
      exposure:
        include: '*'
feign:
  sentinel:
    enabled: true # 激活Sentinel对Feign的支持

  • 访问控制台：http://localhost:8080 登录账号密码均为sentinel，sentinel控制台采用懒加载机制，需要先执行一次请求才会在控制台实时监控微服务

流控规则

image-20200905125829275

Warm Up 预热：

公式:阈值除以coldFactor(默认值为3)，经过预热时长后才会达到阈值

默认coldFactor为3，即请求QPS从threshold/3开始，经预热时长逐渐升至设定的QPS阈值

  • 应用场景：

如：秒杀系统在开启瞬间，会有很多流量上来，很可能把系统打死，预热方式就是为了保护系统，可慢慢的把流量放进来，慢慢的把阈值增长到设置的阈值。

排队等待：

一秒钟只能通过阈值的请求数量

降级规则

image-20200905162717618

RT

image-20200905170828023

异常比例

image-20200905172323176

热点key限流

官方文档：https://github.com/alibaba/Sentinel/wiki/热点参数限流

@GetMapping("/testHotKey")  // value = "testHotKey"表示该方法第一个请求参数只要QPS超过设置的阈值，马上降级处理
@SentinelResource(value = "testHotKey",blockHandler = "deal_testHotKey")  // 分别为资源名称（请求方法名）和降级处理方法
public String testHotKey(@RequestParam(value = "p1",required = false) String p1,
                         @RequestParam(value = "p2",required = false) String p2)
{
    return "------testHotKey";
}
public String deal_testHotKey (String p1, String p2, BlockException exception)
{
    return "------deal_testHotKey,o(╥﹏╥)o";  //sentinel系统默认的提示：Blocked by Sentinel (flow limiting)
}

参数例外项: 我们期望p1参数当它是某个特殊值时，它的限流值和平时不一样

@SentinelResource

相当于Hystrix的 @HystrixCommand，底层代码由try-catch-finally实现的

  • 配置降级处理方法： @SentinelResource(value = "xxx", blockHandler = "xx")
  • 配置降级处理类中的处理方法： @SentinelResource(value = "xxx",blockHandlerClass = xxx.class, blockHandler = "xxx")
Sentinel主要有三个核心Api：sphU定义资源、Tracer定义统计、ContextUtil定义了上下文

服务熔断功能

sentinel整合ribbon+openFeign+fallback

fallback 和 blockHandler

fallback只负责业务异常、运行异常，而blockHandler负责sentinel配置违规、请求错误进行降级处理
 @SentinelResource(value = "fallback",fallback = "handlerFallback",blockHandler = "blockHandler",
            exceptionsToIgnore = {IllegalArgumentException.class}) // 可以设置排除某个异常从而不进入fallback

sentinel配合Openfeign

  • yml

    # 激活Sentinel对Feign的支持
feign:
  sentinel:
    enabled: true

持久化规则

一旦我们重启应用,sentinel规则消失,生产环境需要将配置规则进行持久化
解决：将限流规则持久进Nacos保存,只要刷新8401某个rest地址,sentinel控制台的流控规则就能看得到,只要Nacos里面的配置不删除,针对8401上的流控规则持续有效

  • pom依赖：sentinel-datasource-nacos

  • yml添加Nacos数据源配置，与Nacos连接绑定

    spring:
  cloud:
    sentinel:
      datasource:
        ds1:
          nacos:
            server-addr: localhost:8848
            dataId: cloudalibaba-sentinel-service
            groupId: DEFAULT_GROUP
            data-type: json
            rule-type: flow

  • 添加Nacos业务规则配置

image-20200905212129737

image-20200905212152816

  • 重启sentinel微服务后，刷新sentinel发现nacos刚配置的流控规则还存在

Seata处理分布式事务

全局唯一的事务id，类似一个班学生的班级号是全局唯一的

三组件概念

  • 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) ： 事务管理器。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（到TC）
  • Resource Manager(RM)：资源管理器。控制分支事务,负责分支注册、状态汇报,并接受事务协调的指令,驱动分支(本地)事务的提交和回滚

TC：讲课老师 TM：班主任 RM：学生 XID：班级号

image-20200905215924096

玩法

本地@Transational、全局@GlobalTranstional

  • 1、seata-server-0.9.0.zip解压到指定目录，备份后修改conf目录下的file.conf配置文件。主要修改:自定义事务组名称+事务日志存储模式为db+数据库连接

    • service模块：自定义事务组名称， 在service内添加：vgroup_mapping_test_tx_group = ‘xxx_tx_group’

      image-20200905223846013

    • store模块：事务日志存储模式为db+数据库连接

      store{
	mode: 'db'
}
db {  #修改数据连接信息
}

  • 2、mysql5.7数据库新建库seata。 建表db_store.sql在seata-server-0.9.0\seata\conf目录里面

  • 3、修改seata-server-0.9.0\seata\conf目录下的registry.conf目录下的registry.conf配置文件image-20200905224729726

下单案例

订单/库存/账户业务数据库准备

创建业务数据库

  • seata_order:存储订单的数据库、seata_order库下新建t_order表

    DROP TABLE IF EXISTS `t_order`;
CREATE TABLE `t_order`  (
  `int` bigint(11) NOT NULL AUTO_INCREMENT,
  `user_id` bigint(20) 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',
  PRIMARY KEY (`int`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '订单表' ROW_FORMAT = Dynamic;

  • seata_storage:存储库存的数据库、seata_storage库下新建t_storage表

    DROP TABLE IF EXISTS `t_storage`;
CREATE TABLE `t_storage`  (
  `int` bigint(11) NOT NULL AUTO_INCREMENT,
  `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',
  PRIMARY KEY (`int`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '库存' ROW_FORMAT = Dynamic;
INSERT INTO `t_storage` VALUES (1, 1, 100, 0, 100);

  • seata_account:存储账户信息的数据库、seata_account库下新建t_account表

    CREATE TABLE `t_account`  (
  `id` bigint(11) NOT NULL COMMENT 'id',
  `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 '已用余额',
  `residue` decimal(10, 0) DEFAULT NULL COMMENT '剩余可用额度',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '账户表' ROW_FORMAT = Dynamic;
 
INSERT INTO `t_account` VALUES (1, 1, 1000, 0, 1000);

  • 按照上述3库分别建立对应的回滚日志表,

    订单-库存-账户3个库下都需要建各自独立的回滚日志表 : seata-server-0.9.0\seata\conf\目录下的db_undo_log.sql

订单/库存/账户业务微服务准备

下订单->减库存->扣余额->改(订单)状态。若其中一环出错，数据需要回滚

  • 新建订单、库存、账户三个微服务。以订单为例

  • pom：nacos、seata、openfeign、web、actuator、mysql、druid、mybatis、test、lombok

    		<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>

  • yml

    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

  • file.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" # 需要修改自定义事务组名称

  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"  # 需要修改数据源连接配置
    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
  }
}

  • register.conf

    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"
  }
}

  • domain：Order.class

    @Data
@AllArgsConstructor
@NoArgsConstructor
public class Order
{
    private Long id;
    private Long userId;
    private Long productId;
    private Integer count;
    private BigDecimal money;
    private Integer status; //订单状态：0：创建中；1：已完结
}

  • OrderDao.class

    @Mapper
public interface OrderDao
{
    //1 新建订单
    void create(Order order);
    //2 修改订单状态，从零改为1
    void update(@Param("userId") Long userId,@Param("status") Integer status);
}

  • OrderMapper.xml

    <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>

  • 3个service，分别是订单service、远程调用账户微服务service、远程调用库存微服务service

  • AccountService

    @FeignClient(value = "seata-account-service")
public interface AccountService
{
    @PostMapping(value = "/account/decrease")
    CommonResult decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}

  • StorageService

    @FeignClient(value = "seata-storage-service")
public interface StorageService
{
    @PostMapping(value = "/storage/decrease")
    CommonResult decrease(@RequestParam("productId") Long productId, @RequestParam("count") Integer count);
}

  • OrderService

    public interface OrderService
{
    void create(Order order);
}

  • MyBatisConfig

    @Configuration
@MapperScan({"com.atguigu.springcloud.alibaba.dao"})
public class MyBatisConfig {
}

  • DataSourceProxyConfig

    // 使用Seata对数据源进行代理
@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();
    }
}

  • 启动类

    @EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源的自动创建
public class SeataOrderMainApp2001
{
    public static void main(String[] args)
    {
        SpringApplication.run(SeataOrderMainApp2001.class, args);
    }
}

@GlobalTransactional

  • serviceImpl

        @Override   // 整个业务一发生异常，全局回滚
    @GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
    public void create(Order order)
    {
        log.info("----->开始新建订单");
        //1 新建订单
        orderDao.create(order);

        //2 扣减库存
        log.info("----->订单微服务开始调用库存，做扣减Count");
        storageService.decrease(order.getProductId(),order.getCount());
        log.info("----->订单微服务开始调用库存，做扣减end");

        //3 扣减账户
        log.info("----->订单微服务开始调用账户，做扣减Money");
        accountService.decrease(order.getUserId(),order.getMoney());
        log.info("----->订单微服务开始调用账户，做扣减end");

        //4 修改订单状态，从零到1,1代表已经完成
        log.info("----->修改订单状态开始");
        orderDao.update(order.getUserId(),0);
        log.info("----->修改订单状态结束");

        log.info("----->下订单结束了，O(∩_∩)O哈哈~");
    }

Seata原理

  • 哪个业务service加了@GlobalTransactional注解，就是事务发起方TM， TC就是seata服务器 ，一个数据库就是一个事务参与方RM

分布式事务的执行流程

  • TM开启分布式事务(TM向TC注册全局事务记录)
  • 按业务场景,编排数据库、服务等事务内资源(RM向TC汇报资源准备状态)
  • TM结束分布式事务,事务一阶段结束(TM通知TC提交/回滚分布式事务)
  • TC汇报事务信息,决定分布式事务是提交还是回滚
  • TC通知所有RM提交/回滚资源,事务二阶段结束

SEATA四大模式

AT模式（默认）、TCC模式、SAGA模式、XA模式

AT模式

能做到对业务无侵入

前提：基于支持本地ACID事务的关系型数据库，通过JDBC访问数据库

整体机制

  • 一阶段：业务数据和回滚日志记录在同一个本地事务中提交，释放本地和连接资源

  • 二阶段：

    • 提交异步化，非常快速地完成
    • 回滚通过阶段一的回滚日志进行反向补偿

一阶段加载

·

二阶段提交

1.收到TC的分支提交请求，把请求放入一个异步任务的队列中，马上返回提交成功的结果给TC

2.异步任务阶段的分支提交请求将异步和批量地删除相应的UNDO LOG记录（快照数据）

image-20200906123548027

二阶段回滚

image-20200906123615888

OSS

/**
 * 1、引入oss-starter
 * 2、在application配置key，endpoint相关信息即可
     alicloud:
      access-key: LTAI4G3SehuZHENZA3FxE7ye
      secret-key: XuCsjuSidrTFu7uysdy3G9amFRCShV
      oss:
        endpoint: oss-cn-shenzhen.aliyuncs.com
 * 3、使用OSSClient 进行相关操作
 */
 	@Autowired
	OSSClient ossClient;

	@Test
	public void testUpload() throws FileNotFoundException {
        
// 上传文件流。
		InputStream inputStream = new FileInputStream("D:\\JAVA\\Java_Learning\\IDEA_Project02\\gulimall\\2b1837c6c50add30.jpg");
		ossClient.putObject("gulimall-javajayv", "2b1837c6c50add30.jpg", inputStream);

// 关闭OSSClient。
		ossClient.shutdown();
	}

服务端签名后直传

客户端请求服务端，服务端返回签名，客户端直接访问oss即可

posted @ 2020-11-20 20:02  JavaJayV  阅读(98)  评论(0)    收藏  举报