项目终于用上了Spring状态机，非常优雅！

Bald_eagle

发布于 2023-11-10 12:02

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3.3 测试验证

1）验证业务

新增一个订单
http://localhost:8084/order/create
对订单进行支付
http://localhost:8084/order/pay?id=2
对订单进行发货
http://localhost:8084/order/deliver?id=2
对订单进行确认收货
http://localhost:8084/order/receive?id=2

正常流程结束。如果对一个订单进行支付了，再次进行支付，则会报错：http://localhost:8084/order/pay?id=2

报错如下：

项目终于用上了Spring状态机，非常优雅！-鸿蒙开发者社区

2）验证持久化

内存

使用内存持久化类持久化：

 /**
 * author：公众号：码猿技术专栏
 */ 
 @Resource
    private StateMachinePersister<OrderStatus, OrderStatusChangeEvent, String> stateMachineMemPersister;
    
    /**
     * 发送订单状态转换事件
     * synchronized修饰保证这个方法是线程安全的
     *
     *     @param changeEvent
     *     @param order
     *     @return
     */
    private synchronized boolean sendEvent(OrderStatusChangeEvent changeEvent, Order order) {
        boolean result = false;
        try {
            //启动状态机
            orderStateMachine.start();
            //尝试恢复状态机状态
            stateMachineMemPersister.restore(orderStateMachine, String.valueOf(order.getId()));
            Message message = MessageBuilder.withPayload(changeEvent).setHeader("order", order).build();
            result = orderStateMachine.sendEvent(message);
            //持久化状态机状态
            stateMachineMemPersister.persist(orderStateMachine, String.valueOf(order.getId()));
        } catch (Exception e) {
            log.error("订单操作失败:{}", e);
        } finally {
            orderStateMachine.stop();
        }
        return result;
    }

redis持久化

引入依赖：

<!-- redis持久化状态机 -->
<dependency>
    <groupId>org.springframework.statemachine</groupId>
    <artifactId>spring-statemachine-redis</artifactId>
    <version>1.2.9.RELEASE</version>
</dependency>

配置yaml：

spring:
  redis:
    database: 0
    host: localhost
    jedis:
      pool:
        max-active: 8
        max-idle: 8
        max-wait: ''
        min-idle: 0
    password: ''
    port: 6379
    timeout: 0

使用redis持久化类持久化：

 /**
 * author：公众号：码猿技术专栏
 */ 
 @Resource
    private StateMachinePersister<OrderStatus, OrderStatusChangeEvent, String> stateMachineRedisPersister;
    
    /**
     * 发送订单状态转换事件
     * synchronized修饰保证这个方法是线程安全的
     *
     *     @param changeEvent
     *     @param order
     *     @return
     */
    private synchronized boolean sendEvent(OrderStatusChangeEvent changeEvent, Order order) {
        boolean result = false;
        try {
            //启动状态机
            orderStateMachine.start();
            //尝试恢复状态机状态
            stateMachineRedisPersister.restore(orderStateMachine, String.valueOf(order.getId()));
            Message message = MessageBuilder.withPayload(changeEvent).setHeader("order", order).build();
            result = orderStateMachine.sendEvent(message);
            //持久化状态机状态
            stateMachineRedisPersister.persist(orderStateMachine, String.valueOf(order.getId()));
        } catch (Exception e) {
            log.error("订单操作失败:{}", e);
        } finally {
            orderStateMachine.stop();
        }
        return result;
    }

3.4 状态机存在的问题

1）stateMachine无法抛出异常，异常会被状态机给消化掉

问题现象

从orderStateMachine.sendEvent(message);获取的结果无法感知到。无论执行正常还是抛出异常，都返回true。

 @Resource
    private OrderMapper orderMapper;
    
    @Resource
    private StateMachine<OrderStatus, OrderStatusChangeEvent> orderStateMachine;
    
    @OnTransition(source = "WAIT_PAYMENT", target = "WAIT_DELIVER")
    @Transactional(rollbackFor = Exception.class)
    public void payTransition(Message<OrderStatusChangeEvent> message) {
        Order order = (Order) message.getHeaders().get("order");
        log.info("支付，状态机反馈信息：{}",  message.getHeaders().toString());
        try {
            //更新订单
            order.setStatus(OrderStatus.WAIT_DELIVER.getKey());
            orderMapper.updateById(order);
            //TODO 其他业务
            //模拟异常
            if(Objects.equals(order.getName(),"A")){
                throw new RuntimeException("执行业务异常");
            }
        } catch (Exception e) {
            //如果出现异常，记录异常信息，抛出异常信息进行回滚
            log.error("payTransition 出现异常：{}",e);
            throw e;
        }
    }

监听事件抛出异常，在发送事件中无法感知：

private synchronized boolean sendEvent(OrderStatusChangeEvent changeEvent, Order order) {
        boolean result = false;
        try {
            //启动状态机
            orderStateMachine.start();
            //尝试恢复状态机状态
            stateMachineMemPersister.restore(orderStateMachine, String.valueOf(order.getId()));
            Message message = MessageBuilder.withPayload(changeEvent).setHeader("order", order).build();
             //事件执行异常了，依然返回true，无法感知异常
            result = orderStateMachine.sendEvent(message);
            if(result){
                //持久化状态机状态，如果根据true持久化，则会出现问题
                stateMachineMemPersister.persist(orderStateMachine, String.valueOf(order.getId()));
            }
        } catch (Exception e) {
            log.error("订单操作失败:{}", e);
        } finally {
            orderStateMachine.stop();
        }
        return result;
    }

调试发现：发送事件和监听事件是一个线程，发送事件的结果是在监听操作执行完之后才返回

项目终于用上了Spring状态机，非常优雅！-鸿蒙开发者社区

监听线程：

项目终于用上了Spring状态机，非常优雅！-鸿蒙开发者社区

解决方案：自己保存异常到数据库或者内存中，进行判断

也可以通过接口：org.springframework.statemachine.StateMachine##getExtendedState

方法把执行状态放入这个变量中

public interface ExtendedState {
        Map<Object, Object> getVariables();
        <T> T get(Object var1, Class<T> var2);
        void setExtendedStateChangeListener(ExtendedState.ExtendedStateChangeListener var1);
        public interface ExtendedStateChangeListener {
            void changed(Object var1, Object var2);
        }
    }

org.springframework.statemachine.support.DefaultExtendedState##getVariables

private final Map<Object, Object> variables;
    
    public DefaultExtendedState() {
        this.variables = new ObservableMap(new ConcurrentHashMap(), new DefaultExtendedState.LocalMapChangeListener());
    }
    
    public Map<Object, Object> getVariables() {
        return this.variables;
    }

改造监听状态：把业务的执行结果进行保存，1成功，0失败


    @Resource
    private OrderMapper orderMapper;
    @Resource
    private StateMachine<OrderStatus, OrderStatusChangeEvent> orderStateMachine;
    
    @OnTransition(source = "WAIT_PAYMENT", target = "WAIT_DELIVER")
    @Transactional(rollbackFor = Exception.class)
    public void payTransition(Message<OrderStatusChangeEvent> message) {
        Order order = (Order) message.getHeaders().get("order");
        log.info("支付，状态机反馈信息：{}",  message.getHeaders().toString());
        try {
            //更新订单
            order.setStatus(OrderStatus.WAIT_DELIVER.getKey());
            orderMapper.updateById(order);
            //TODO 其他业务
            //模拟异常
            if(Objects.equals(order.getName(),"A")){
                throw new RuntimeException("执行业务异常");
            }
            //成功 则为1
            orderStateMachine.getExtendedState().getVariables().put(CommonConstants.payTransition+order.getId(),1);
        } catch (Exception e) {
            //如果出现异常，则进行回滚
            log.error("payTransition 出现异常：{}",e);
            //将异常信息变量信息中，失败则为0
            orderStateMachine.getExtendedState().getVariables().put(CommonConstants.payTransition+order.getId(), 0);
            throw e;
        }
    }

发送事件改造：如果获取到业务执行异常，则返回失败，不进行状态机持久化 com.zengqingfa.springboot.state.demo.service.impl.OrderServiceImpl##sendEvent

 @Resource
    private StateMachine<OrderStatus, OrderStatusChangeEvent> orderStateMachine;
    @Resource
    private StateMachinePersister<OrderStatus, OrderStatusChangeEvent, String> stateMachineMemPersister;
    
    /**
     * 发送订单状态转换事件
     * synchronized修饰保证这个方法是线程安全的
     *
     *     @param changeEvent
     *     @param order
     *     @return
     */
    private synchronized boolean sendEvent(OrderStatusChangeEvent changeEvent, Order order){
        boolean result = false;
        try {
            //启动状态机
            orderStateMachine.start();
            //尝试恢复状态机状态
            stateMachineMemPersister.restore(orderStateMachine, String.valueOf(order.getId()));
            Message message = MessageBuilder.withPayload(changeEvent).setHeader("order", order).build();
            result = orderStateMachine.sendEvent(message);
            if(!result){
                return false;
            }
            //获取到监听的结果信息
            Integer o = (Integer) orderStateMachine.getExtendedState().getVariables().get(CommonConstants.payTransition + order.getId());
            //操作完成之后,删除本次对应的key信息
            orderStateMachine.getExtendedState().getVariables().remove(CommonConstants.payTransition+order.getId());
            //如果事务执行成功，则持久化状态机
            if(Objects.equals(1,Integer.valueOf(o))){
                //持久化状态机状态
                stateMachineMemPersister.persist(orderStateMachine, String.valueOf(order.getId()));
            }else {
                //订单执行业务异常
                return false;
            }
        } catch (Exception e) {
            log.error("订单操作失败:{}", e);
        } finally {
            orderStateMachine.stop();
        }
        return result;
    }

代码优化

发送事件只针对了支付，如果是非支付事件呢？

//获取到监听的结果信息
Integer o = (Integer) orderStateMachine.getExtendedState().getVariables().get(CommonConstants.payTransition + order.getId());

监听设置状态的代码有重复代码，需要进行优化，可使用aop

try {
        //TODO 其他业务
        //成功 则为1
        orderStateMachine.getExtendedState().getVariables().put(CommonConstants.payTransition+order.getId(),1);
    } catch (Exception e) {
        //如果出现异常，则进行回滚
        log.error("payTransition 出现异常：{}",e);
        //将异常信息变量信息中，失败则为0
        orderStateMachine.getExtendedState().getVariables().put(CommonConstants.payTransition+order.getId(), 0);
        throw e;
    }

常量类：

public interface CommonConstants {
        String orderHeader="order";
        String payTransition="payTransition";
        String deliverTransition="deliverTransition";
        String receiveTransition="receiveTransition";
    }

支付发送事件：com.zengqingfa.springboot.state.demo.service.impl.OrderServiceImpl##pay

 @Resource
    private StateMachine<OrderStatus, OrderStatusChangeEvent> orderStateMachine;
    @Resource
    private StateMachinePersister<OrderStatus, OrderStatusChangeEvent, String> stateMachineMemPersister;
    @Resource
    private OrderMapper orderMapper;
    
    /**
     * 对订单进行支付
     *
     *     @param id
     *     @return
     */
    public Order pay(Long id) {
        Order order = orderMapper.selectById(id);
        log.info("线程名称：{},尝试支付，订单号：{}" ,Thread.currentThread().getName() , id);
        if (!sendEvent(OrderStatusChangeEvent.PAYED, order,CommonConstants.payTransition)) {
            log.error("线程名称：{},支付失败, 状态异常，订单信息：{}", Thread.currentThread().getName(), order);
            throw new RuntimeException("支付失败, 订单状态异常");
        }
        return order;
    }
    
    /**
     * 发送订单状态转换事件
     * synchronized修饰保证这个方法是线程安全的
     *
     *     @param changeEvent
     *     @param order
     *     @return
     */
    private synchronized boolean sendEvent(OrderStatusChangeEvent changeEvent, Order order,String key){
        boolean result = false;
        try {
            //启动状态机
            orderStateMachine.start();
            //尝试恢复状态机状态
            stateMachineMemPersister.restore(orderStateMachine, String.valueOf(order.getId()));
            Message message = MessageBuilder.withPayload(changeEvent).setHeader("order", order).build();
            result = orderStateMachine.sendEvent(message);
            if(!result){
                return false;
            }
            //获取到监听的结果信息
            Integer o = (Integer) orderStateMachine.getExtendedState().getVariables().get(key + order.getId());
            //操作完成之后,删除本次对应的key信息
            orderStateMachine.getExtendedState().getVariables().remove(key+order.getId());
            //如果事务执行成功，则持久化状态机
            if(Objects.equals(1,Integer.valueOf(o))){
                //持久化状态机状态
                stateMachineMemPersister.persist(orderStateMachine, String.valueOf(order.getId()));
            }else {
                //订单执行业务异常
                return false;
            }
        } catch (Exception e) {
            log.error("订单操作失败:{}", e);
        } finally {
            orderStateMachine.stop();
        }
        return result;
    }

使用aop对监听事件切面，把业务执行结果封装到状态机的变量中，注解：

 @Retention(RetentionPolicy.RUNTIME)
    public @interface LogResult {
        /**
         *执行的业务key
         *
         *     @return String
         */
        String key();
    }

切面：

 @Component
    @Aspect
    @Slf4j
    public class LogResultAspect {
    
        //拦截 LogHistory注解
        @Pointcut("@annotation(com.zengqingfa.springboot.state.demo.aop.annotation.LogResult)")
        private void logResultPointCut() {
            //logResultPointCut 日志注解切点
        }
        @Resource
        private StateMachine<OrderStatus, OrderStatusChangeEvent> orderStateMachine;
        
        @Around("logResultPointCut()")
        public Object logResultAround(ProceedingJoinPoint pjp) throws Throwable {
            //获取参数
            Object[] args = pjp.getArgs();
            log.info("参数args:{}", args);
            Message message = (Message) args[0];
            Order order = (Order) message.getHeaders().get("order");
            //获取方法
            Method method = ((MethodSignature) pjp.getSignature()).getMethod();
            // 获取LogHistory注解
            LogResult logResult = method.getAnnotation(LogResult.class);
            String key = logResult.key();
            Object returnVal = null;
            try {
                //执行方法
                returnVal = pjp.proceed();
                //如果业务执行正常，则保存信息
                //成功 则为1
                orderStateMachine.getExtendedState().getVariables().put(key + order.getId(), 1);
            } catch (Throwable e) {
                log.error("e:{}", e.getMessage());
                //如果业务执行异常，则保存信息
                //将异常信息变量信息中，失败则为0
                orderStateMachine.getExtendedState().getVariables().put(key + order.getId(), 0);
                throw e;
            }
            return returnVal;
        }
    }

监听类使用注解：

 @Component("orderStateListener")
    @WithStateMachine(name = "orderStateMachine")
    @Slf4j
    public class OrderStateListenerImpl {
        @Resource
        private OrderMapper orderMapper;
    
        @OnTransition(source = "WAIT_PAYMENT", target = "WAIT_DELIVER")
        @Transactional(rollbackFor = Exception.class)
        @LogResult(key = CommonConstants.payTransition)
        public void payTransition(Message<OrderStatusChangeEvent> message) {
            Order order = (Order) message.getHeaders().get("order");
            log.info("支付，状态机反馈信息：{}", message.getHeaders().toString());
            //更新订单
            order.setStatus(OrderStatus.WAIT_DELIVER.getKey());
            orderMapper.updateById(order);
            //TODO 其他业务
            //模拟异常
            if (Objects.equals(order.getName(), "A")) {
                throw new RuntimeException("执行业务异常");
            }
        }
        @OnTransition(source = "WAIT_DELIVER", target = "WAIT_RECEIVE")
        @LogResult(key = CommonConstants.deliverTransition)
        public void deliverTransition(Message<OrderStatusChangeEvent> message) {
            Order order = (Order) message.getHeaders().get("order");
            log.info("发货，状态机反馈信息：{}", message.getHeaders().toString());
            //更新订单
            order.setStatus(OrderStatus.WAIT_RECEIVE.getKey());
            orderMapper.updateById(order);
            //TODO 其他业务
        }
        @OnTransition(source = "WAIT_RECEIVE", target = "FINISH")
        @LogResult(key = CommonConstants.receiveTransition)
        public void receiveTransition(Message<OrderStatusChangeEvent> message) {
            Order order = (Order) message.getHeaders().get("order");
            log.info("确认收货，状态机反馈信息：{}", message.getHeaders().toString());
            //更新订单
            order.setStatus(OrderStatus.FINISH.getKey());
            orderMapper.updateById(order);
            //TODO 其他业务
        }
    }

文章转载自公众号：码猿技术专栏

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已于2023-11-10 12:02:19修改

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项目终于用上了Spring状态机，非常优雅！

3.3 测试验证

1）验证业务

2）验证持久化

3.4 状态机存在的问题

1）stateMachine无法抛出异常，异常会被状态机给消化掉

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